Whoa, you're using an old browsers aren't you? This site would look better if you upgraded. We recommend Mozilla Firefox

NE1035: Commercial Greenhouse Production: Component and System Development

Annual/Termination Reports (SAES-422): [08/11/2009] [05/20/2010] [09/20/2011] [08/22/2012]

Date of Annual Report: 08/11/2009

Report Information:
  • Annual Meeting Dates: 06/14/09 to 06/19/09
  • Period the Report Covers: 06/2008 to 05/2009

    • Participants:

    URL: Copy of participant list
    Brief Summary of Minutes of Annual Meeting:

    URL: Copy of minutes
    Accomplishments:
    Multistate Research Project Annual Station Accomplishments Report

    Topic 1: Energy conservation and alternative energy sources 1. Evaluate biomass derived fuels for greenhouse heating (NE, NJ, NY).

    NE has secured two double poly grower-type greenhouses on campus - one is being heated by natural gas and cooled by ventilation and evaporative pads. It has been monitored and data recorded at 10-minute basis since January using a similar LabVIEW adaptive model and data acquisition system described in the report. We have an excellent record of spatial and diurnal quantum and total radiation during this production period, along with diurnal temperatures and the operational events for the Groton II controller used. We are also working with web cam technology to visually and through machine vision follow crop growth and development. The second campus house will be glazed with double poly this summer, instrumented, and will use a prototype portable greenhouse pellet burner built by Heat Source One of Beatrice, NE. The campus and the commercial houses are of similar size and design and in a NS orientation. These greenhouses are internet accessible. The plan for NE this fall is to investigate potential improvement in quantum availability to the canopy using reflective mulches and poly films. We also plan to develop a physiological (including sugar and nutraceutical properties), a production plan, a market plan and a database for growing 16 selected cultivars of day neutral strawberries. The software and model developed will allow us to capture the growth and development information and concurrently evaluate heating and ventilation operation, costs, and efficiencies in real time.

    2. Develop decision support systems for alternative fuel heating systems (NJ, NE, NY, PA, CT).

    Coordinated control of daily light integral and CO2 concentration (NY) In previous work at Cornell, a patented control algorithm was developed that demonstrates synergistic environmental control involving supplemental lights, moveable shades and CO2 supplementation. Outdoor air temperature and the expected solar integral for the next hour are predicted based on data collected in the previous several hours. An energy balance predicts the ventilation rate required to control temperature for the next hour. A growth model utilizing CO2 concentration and daily light integral is then utilized to develop costs associated with providing a consistent level of growth with varying levels of CO2 and supplemental light. For each combination the cost of supplemental CO2 is compared to savings of supplemental light and the least cost combination is chosen. This control algorithm was implemented in a greenhouse compartment at Cornell, and lettuce crops were grown under these conditions; CO2 use and lighting energy data were collected for 3 months. Over the course of the experiment the CO2 Light controller successfully produced consistent daily growth that used 37% less supplemental lighting than a light integral controller alone. The greenhouse used for this research was particularly dark (approximately 50% light transmission); we expect the percentage savings to be greater in a more typical commercial greenhouse.

    Energy comparisons of several imported vs. locally-grown foods (NY) The impending probable shortage of liquid fuels has alerted policy makers and the public that we need to account for the energy needs of agricultural production and the energy costs of bringing food to our tables. It is for these reasons that energy budgets and types of energy used in food production are of great interest. In the following, the energy use being compared is only that part supplied by humans at a cost. The energy accounted for is that delivered as electricity and various fossil fuels used for crop production (called direct energy), and that required to manufacture building materials, tillage equipment, and supplies such as fertilizer and pesticides (called embodied energy). The energy to extract fossil fuels and generate electricity is also taken into account; it can be considered to be embodied energy. It requires money to acquire and manipulate the energy we are accounting for, and its use results in carbon dioxide and other greenhouse gas emissions.

    Topic 2: Water and nutrient solution management

    3. Develop protocols for irrigation that maximize water use efficiency while maintaining crop growth and quality (CT, ME, NE, PA, NY, OH, AZ).

    Machine Vision Guided System for Plant Health and Growth Monitoring in Controlled Environment Agriculture Production (AZ) In progress: Dr. Kacira's lab has been working on development of a sensing and control lab at the University of Arizona Controlled Environment Agriculture Center (UA-CEAC) to assess plant growth, quality and health. A machine vision system has been designed, constructed and it is under operation. Machine vision system autonomously monitors textural, color, and temporal features of experimental plants to determine plant health, growth and early symptoms of stresses. The capability of the system is currently being evaluated for detection of tipburn on lettuce growing in a floating hydroponics setting. The monitoring system is capable of extracting plant morphological, textural and temporal features evaluated. The extracted plant parameters; top projected canopy area, entropy, energy, contrast, and homogeneity and these features showed promising signals for detection of lettuce tipburn occurrence. However, experiments are in progress to further evaluate these plant features and system capability on early tipburn detection. The ultimate goal of the system being developed is to establish a multi-sensor based plant monitoring platform for plant health/quality monitoring and resource savings in CE plant production.

    Sustainable Resource Management and Year Round Production of Fresh Green Salad Crops With Automated and Remotely Monitored Controlled Environment Plant Production Systems (AZ) An automated and remotely monitored three floating hydroponic system (FHS) was designed and constructed at the CEAC for research. The potential sustainable management of reduced and reused water and fertilizer in this hydroponic systems is being evaluated for production of fresh green salad crops. The automated FHS units are remotely monitored using LabView platform for parameters including EC, pH, dissolved oxygen and nutrient temperature in the root zone, and air temperature, relative humidity, light intensity, and CO2 concentration in the aerial environment. Currently, strategies were also developed to control the temperature and pH in the nutrient zone. Research is continuing on the dynamics of the system, and the effects of electrical conductivity, pH and water temperature on plant growth, quality and phytochemical yield, and energy input-output analysis in the production system.

    Integrative Farming Practices for Sustainable Food Production (AZ) A state of the art controlled environment aquaponics research greenhouse was designed and engineered for intensive fish and vegetable production. Aquaponics is the integration of recirculating aquaculture and hydroponic plant systems. This system allows for reuse of water to produce lettuce in an efficient and sustainable manner. Research goals of the project include determining the biomass production (fish and plants) that can be achieved per unit of resources (water, nutrients, space), exploring the physiological interactions in a controlled environment aquaponics system, determining the water use efficiency of aquaponic systems, and developing production techniques for large scale applications. System output is determined by the overall biomass production of fish and plants. The Feed Conversion Ratio (FCR) is used to measure the production efficiency of fish. Plant biomass and Chlorophyll Concentration Indices are used to determine plant growth and quality. Environmental monitoring and control consists of air temperature, relative humidity and photosynthetic active radiation (PAR). Water temperature, pH, electrical conductivity, and dissolved oxygen are monitored and controlled. The complete water chemistry of the system is analyzed on a biweekly basis. The research greenhouse has been operating for one year and has established a synergistic relationship between the fish component, the filtration (biological, mechanical and chemical) component, and the hydroponic plant component. Current research has focused on Oreochromis niloticus spp. (Tilapia) and Lactuca sativa cultivars (lettuce). Fish effluent is a sustainable and efficient nutrient source for plant production and plant uptake and deposition of nutrients is an environmentally friendly means of filtration.

    ME and GA are collaborating with Jonathan Frantz from the USDA-ARS to develop predictive models that will estimate water use of Euphorbia pulcherrima and Petunia × hybrida based on changes in vapor pressure deficit, temperature, and photosynthetic photon flux density. This model, once developed, will be included in the USDA-ARS program, Virtual Grower, which is available free to growers (http://www.ars.usda.gov/services/software/download.htm?softwareid=108). In ME Heuchera americana 'Dale's Strain' were grown in a capacitance automated irrigation system at volumetric water contents (VWC) set points of 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50 L L-1. The volume of water applied to plants ranged from 2.5 to 5 L over a 50 d cropping cycle. Water use efficiency (g of shoot biomass/L of water applied) decreased as plants were irrigated at higher VWC set points. Of morphological variables measured (height, width, length of petiole, and number of leaves), VWC only significantly affected leaf area at the end of the cropping cycle. Leaf area increased with increasing VWC set point (range = 800 to 1600 cm2). A minimum VWC of 0.3 L L-1 is recommended for irrigation of Heuchera americana 'Dale's Strain' to avoid this reduction in leaf area.

    KY developed a photosynthesis-based irrigation model for Hibiscus 'Cashmere Wind' under controlled-environment conditions. This model was based on the relationship between substrate moisture content and photosynthetic rate. A sigmoidal equation best fit the curve (r2=0.62). Photosynthesis was maintained at or near maximum rates from 100% container capacity to 62% container capacity. A distinct decrease in photosynthesis was apparent at 61% container capacity and this was used as an irrigation set point. Subsequent experiments showed that biomass and quality could be maintained equally among irrigation treatments so long as substrate moisture content was maintained above this set point.

    Precise Nursery Water and Nutrient Delivery System (OH) Over a four-year period, a new water and nutrient delivery system was designed and constructed to accurately and precisely deliver nutrient solutions during relatively short irrigation events (5 to 10 min) in small volumes (10 to 50 L) to small numbers of container-grown plants typically required for specified treatments in research plots. The system was delivered to the Ohio Agricultural Research and Development Center (OARDC), Wooster, Ohio, for beta testing by Argus Control Systems Limited, White Rock, British Columbia on December 15, 2006. The unit was tested summer 2008 and summer 2009. Current results indicate the accuracy of nutrient delivery for the Argus Nutrient Delivery System is equal to or better than +/- 3% of specified target concentrations. These conclusions are based on a precise, nutrient system calibration procedure developed at the OARDC followed by daily pH and EC measurements.

    Willoway Nurseries, Inc., Avon, Ohio, Bill Bauerle and Robert Hansen agreed to set up experiments to measure volumetric water content (VWC) and EC in container-grown plants as a basis for understanding leaching, water and nutrient delivery efficiencies, and optimizing systems for recycling water and nutrients. Twenty VWC sensors for making these measurements (Decagon ECH20-TE) and four data loggers (Decagon Em50) were purchased and tested in preparation for installation, summer 2009. The capability of these sensors to decide when and how much to irrigate pot-in-pot, container-grown trees will be evaluated and compared to growers' current practices for scheduling irrigation. In addition, ground up pine bark and hard wood chips are being evaluated as replacement components for container mediums since Canadian Sphagnum Peat Moss has tripled in price during the last year or so. The evaluation will be based on particle size, container capacity, porosity and durability. Newly designed platforms for doing flow-though measurements in the field were designed and constructed and will also be available for measuring EC and pH during summer 2009 and comparing results to the ECH20-TE pore water measurements.

    Development of a Simple Test to Determine Capillary Flow in Different Types of Growing Media (PA) We propose to develop a simple and easy to conduct test that will compare capillary flow in various types of growing media. The test method evaluated was based on capillary uptake of a growing medium over a specific time course. Peat was brought to 4 moisture content values (160%, 250%, 390%, and 470%) and pots of moistened peat were placed in contact with water for 30 minutes in a container with the water depth of 1/4-inch. The cumulative water uptake was calculated by subtracting the previous weight from the current weight. The peat with the highest mass wetness values (390 and 470) had similar uptake patterns and the intercepts were similar, but the slope of the 390 moisture content line was 0.42 where as the slope of the 470 moisture content line was 0.29. Peat with an initial moisture content of 250% had a substantially higher slope and a lower intercept while the peat with the lowest moisture content had a steeper slope and a smaller intercept. It is clear that the initial moisture content of the peat will affect measured unsaturated water flow so any test for capillary flow must standardize the starting conditions. Subsequent test development trials when peat was a component of the mix used moisture content standardized to a constant value. In trial 2 moist peat was compared with perlite and a mixture of 50% peat and 50% perlite. The slope and the intercept of cumulative water uptake of peat was similar to that reported in Trial 1. Perlite had a much different intercept and a different slope to the regression line. The mixture of peat and perlite provided an intermediate water uptake. Trial 3 was conducted to provide a comparison of peat, sand and a mixture of peat and sand. The slope and the intercept for peat was different from the first two trials and there is no explanation for that difference at this point. The slope and intercept for sand is much different from either peat or perlite. The water uptake in sand is extremely rapid in that in the first minute all the water that could be taken up was taken up. The mixture of peat and sand has a much different slope that was evident for the other materials. The conclusion at this point is that different materials do have different slopes and intercepts so that it should be possible to develop a laboratory test that will permit the characterization of unsaturated water flow in commercial growing media.

    Fertilization Strategies to Reduce Substrate Salt Accumulation in Sub-Irrigation Systems (NY) The objective of this project was to determine the influence of fertilizer concentration and irrigation method (sub- versus overhead irrigation) on the growth of several bedding plant species. Seedlings were transplanted into ten centimeter pots with a peat-based medium. Irrigation provided via ebb and flow benches (subirrigation) or hand watering (overhead). Within each greenhouse plants received a complete fertilizer solution provided at a concentration of 0.25, 0.50, 1.0, 1.75, and 2.5 dS/m. By the end of the nine week period container medium EC varied from 0.9 to 6.2 dS/m. For plants that received overhead irrigation optimal shoot dry mass (DM) was achieved at: 0.5 dS/m for pepper; 1.0 dS/m for tomato, Antirrhinum, Impatiens, and Torenia; and at 1.75 dS/m for the rest of the species. For the subirrigated plants optimal DM was achieved at: 0.5 dS/m for Antirrhinum, Gazania, Impatiens, and Torenia; 1.0 dS/m for kale, lettuce, pepper, and tomato; and 1.75 dS/m for collards. Our results corroborate previous reports that optimal plant growth often requires lower fertilizer concentrations when subirrigation is used. In several cases DM was negatively affected by high fertilizer concentrations with subirrigation. For example, DM of subirrigated Impatiens declined from 11.6 to 3.4 g/plant as fertilizer concentration increased from 1.0 to 2.5 dS/m.

    Silicon Supplementation to Enhance Abiotic Stress Resistance (NY) Twenty popular bedding plant species were screened for silicon response; half of the species showed enhanced tissue silicon levels when potassium silicate supplementation was added to the fertilizer regime. Dry weight (DW) of three species increased when supplemented with Si, these were Bracteantha (+16%), Lobelia (+19%), and Verbena (+19%). Our results demonstrate that common floriculture species grown in a peat-based substrate do absorb silicon; and that Si supplementation from potassium silicate drenches was effective at increasing leaf Si concentration for about one-half of these crops. More work is needed to determine the appropriate rate of Si supplementation and to examine possible Si benefits under conditions of abiotic stress.

    Silicon Supplementation and Regulated Deficit Irrigation of Poinsettia (NY) To investigate possible beneficial effects of substrate applied Si and Ca in Poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) production. The treatment design was a factorial arrangement having 2 Ca concentrations, 2 Si concentrations, and 3 irrigation regimes. We applied 0 and 56 mg·L-1 Si , 0 and 100 mg·L-1 Ca, as part of regular fertigation.  In addition, plants were given 100, 80 and 60% regulated deficit irrigation (RDI).  Regulated deficit volumes were established gravimetrically using several well watered (100%) reference plants. We observed a significant improvement in postharvest water stress tolerance, as measured by degree of wilt, when plants were supplemented with silicon. Leaf wilt angle was reduced 31% after 5 days of simulated postharvest storage without water. Regardless of nutrition regime, plants subjected to 60 and 80% optimal irrigation exhibited reduced postharvest wilting compared to well watered plants.

      4. Develop irrigation protocols and filtration or sterilization methods for nutrient solution recirculation that minimize the effects of pathogens or toxic metabolites (CT, NY, OH)

    Partial Saturation Ebb and Flow Irrigation (CT) Sub-irrigation for production of potted ornamental plants combats the waste of water and fertilizer in traditional overhead watering systems used in greenhouses. However, current ebb and flow watering systems for flooded floors operate slowly. The root medium takes up water to near saturation during each watering cycle. There is no ability to restrict the water provided to the plants. We have examined a system to rapidly deliver and remove water. Less water is absorbed by the root medium and little if any water drains out of the pots. This improves plant quality and prevents spread of disease. We examined several parameters that vary between this partial saturation ebb and flow watering on a flooded floor compared to full saturation watering. Plants took up 20 to 30% less water and fertilizer. Biomass until flower development and bloom, and stem height, were also reduced by 10 to 20% under partial saturation. In one experiment with Poinsettia, inoculation of some plants with Pythium resulted in wilting of 20 of 240 non-inoculated plants grown under full saturation. No plants were affected under partial saturation. Post harvest quality of leaves and flowers in a controlled environment were similar under the two watering regimes.

    Nursery Water Cleansing System (W. Bauerle, OH) A complete irrigation and water cleansing system was designed and constructed at a large commercial nursery facility. The irrigation and nutrient delivery system featured a special multi headed injection system designed by Bauerle. This Controlled Nutrient Delivery System (CNDS) injects essential, individual plant nutrients that result in the optimization of plant growth and development. The nutrients also result in the increased production of phytoalexins which stimulates the natural plant immune system against pathogenic infections. The water cleansing system was incorporated to control plant pathogens in the recycled effluent water. It was accomplished with the injection of chlorine dioxide into the system.

    Topic 3: Sensors and control systems

    5. Improve volumetric water content sensor efficacy (ME, NY, OH).

    Physical Characterization of a New Substrate for Automated Irrigation Management by Using Microtensiometers (AZ) The objective of this project is to characterize foam glass substrate which is highly porous substrate and the use of a microtensiometer to trigger irrigation, when the matric potential is lower than desired. Experiments with this substrate and stone fibers were conducted at the CEAC-University of Arizona resulting in similar yields with 95% confidence interval. This research involves physical characterization of the foam glass which particle size is < 1.25 cm and the development of a microtensiometer to measure matric potential. The microtensiometer consists on a pressure transducer, stainless steel tubing, stainless steel porous cap and a solid block of the foam glass. The microtensiometer is going to be placed on the substrate bag and it is going to trigger irrigation when the matric potential is less than the desired. Finally, the water movement inside the foam glass growing bag (size: length= 100cm width = 15 cm and height = 15 cm) is going to be simulated by using the software packet Hydrus 3D. The simulation of water flow and the duration of each irrigation are going to be manipulated to have the ideal scenario to maximize water efficiency. The simulations of irrigations are going to be tested in a growing bag with mature tomatoes plants in a greenhouse located at the CEAC-University of Arizona. Plant water status measurements such as lysimeter are going to be conducted in order to avoid plant stress.

    6. Improve sensor control of the greenhouse aerial environment (light, carbon dioxide, temperature, and moisture) (NJ, OH, NY, NE, AZ).

    Greenhouse crop production for local sustainability and self-reliance (AK) Producing greenhouse crops in high latitude locations is demanding. Large seasonal variations in natural day lengths and temperatures require continuous modifications in the greenhouse climate to best conform to outside conditions. There is a demand for suitable greenhouse management procedures to be developed and disseminated to producers in northern and other challenging locations.

    In OH sensors have been installed in a research greenhouse located on Wooster campus, OARDC to validate a model developed for estimating ventilation requirements of a greenhouse to improve CO2 enrichment efficiency. A semi-closed greenhouse is proposed to improve energy and CO2 enrichment efficiency of plant production in greenhouses.

    Topic 4: Environmental effects on plant composition

    7. Develop greenhouse design and management protocols to maintain high nutrition values of vegetable crops grown under various environments (AZ, CT, NJ).

    Effects of Supplemental Light Quality on Growth and Phytochemicals of Baby Leaf Lettuce Grown under White Light (AZ) Using UV-A, blue, green, red, and far-red light-emitting diodes (LEDs), we investigated the effects of different supplemental light qualities on phytochemicals and growth of 'Red Cross' baby leaf lettuce (Lactuca sativa L.) grown at a high planting density under white fluorescent lamps as the main light source inside a growth chamber. After 12 days of light quality treatment (22 days after germination), phytochemical concentration and growth of lettuce plants were significant affected by light treatments. Anthocyanins concentration increased with supplemental UV-A and blue respectively, carotenoids concentration increased with supplemental blue, phenolics concentration increased with supplemental red while supplemental far-red decreased anthocyanins, carotenoids and chlorophyll concentration, compared to those under in the white light control. The fresh weight, dry weight, stem length, leaf length and leaf width significantly increased with supplemental far-red light compared to white light, presumably due to enhanced light interception by enlarged leaf area under supplemental far-red light. The results demonstrated that supplemental light quality could be strategically used to enhance nutritional value and growth of baby leaf lettuce grown under white light.

    Evaluation of Yields and Quality of Baby Salad Leaves (AZ) As part of the on-going collaboration with Dr. Cynthia Thomson at the Department of Nutritional Sciences and Arizona Cancer Center, the Kubota lab is in charge of year-round production of baby leaves (mix of two lettuces and komatsuna). A total of 45 post-menopausal over-weight women are recruited and consuming greenhouse vegetables at three different doses (2, 5, and 10 servings a day) to examine human body response in terms of mitigating oxidative stress by consuming more vegetables. In the Kubota lab, while producing sufficient amounts of study vegetables (baby leaf mix, red pepper, and tomato), we evaluate seasonal changes in yield and the major phytochemical compounds in leaves (carotenoids, anthocyanins, phenolics, and ascorbic acid).

    8. Develop greenhouse design and management protocols to maximize production of beneficial compounds such as phytochemicals and biopharmaceuticals (NY, AZ, CT, MI, NJ).

    Biopharmaceutical Protein Production under Controlled Environments: Growth, Development and Vaccine Productivity of Transgenic Tomato Plants Grown Hydroponically in a Greenhouse (AZ) As the first step toward optimization of greenhouse-based production of plant-made high-value protein, growth and development of transgenic tomato plants were evaluated as well as their fruit and protein productivities. Transgenic tomato expressing a predominant antigen fusion protein F1-V against plague was used as a model system. Transgenic T2 lines, 'F1-V', its background wild-type cultivar, 'TA234',and a commercial greenhouse cultivar, 'Durinta', were grown hydroponically in a greenhouse equipped with a heating and an evaporative cooling system from September 2007 to March 2008. When comparing 'F1-V' with 'Durinta', 'Durinta' yielded more fruit than 'F1-V', although final vegetative biomass of the two genotypes was not significantly different. Cumulative fruit yield per plant of 'Durinta' for 13 weeks of harvests was almost twice that of 'F1-V'. However, total soluble-protein (TSP) concentration of fruits of 'Durinta' was significantly lower than that of 'F1-V', making the estimated cumulative TSP production by fruits lower in 'Durinta'. On the other hand, when comparing 'F1-V' with 'TA234', there were no significant differences neither in vegetative biomass, fruit yield, fruit TSP concentration nor cumulative TSP production between the two genotypes, suggesting that the differences between 'F1-V' and 'Durinta' are related to the difference between the baseline genotypes rather than the transgenic event. Our results suggest that biomass productivity is not necessarily the high priority trait in selecting cultivars for high-value protein production.

    Lighting effects on active metabolite production in St. John's wort (NY) Hypericum perforatum or St. John's wort is a plant grown commercially for use as a medicinal plant. The consistency of secondary metabolites that act as active ingredients in H. perforatum preparations is a constant problem and is attributed partially to environmental conditions experienced by the plants during growth. Controlling the light provided to plants has been an effective way to manipulate plant growth in other crops. The effects of light intensity, quantity and quality on biomass and secondary metabolites hyperforin, pseudohypericin and hypericin over time were investigated in four experiments. Light intensities from 90 to 340 umol m-2 s-1 were investigated while daily light integral was held constant. Effects of daily light integral were demonstrated by holding the light intensity constant and varying the light integral from 8.6 to 20 mol m-2 d-1. The response of metabolite production to the presence or absence of UV-A and UV-B was also explored. Finally, the usefulness of stressing the plants with supplemental UV-B light just prior to harvest was determined. Results showed a very small or no significant increase in the secondary metabolites quantified in response to increasing light intensity, light integral or the addition of UV-A or UV-B light. Biomass production was shown to increase with exposure to increased light intensity and light integral. It was demonstrated that all of the metabolites increased their concentrations as plants transitioned from a vegetative to reproductive state. For growth in controlled environments, increased light integral did increase metabolite production indirectly as biomass increases led to a more rapid time to flowering. Since metabolite concentrations were shown to rise so dramatically when plants were flowering, the best protocol for maximizing metabolite production per square meter of growing space is to furnish plants with as much total light as possible which would hasten the time to flowering, then harvest plant material at the full bloom stage.

    Environmental control to increase genetic expression of valuable chemicals in tobacco (NY) Continuing research uses chloroplast-transformed tobacco cultivars expressing cellulase as model crops with which to determine how to produce pharmaceuticals in controlled environments (CEs) most cost effectively. It was thought unlikely that cellulase enzymes would be a major target chemical for commercial CE production, but it was expected knowledge of the factors affecting the performance of chloroplast transformants expressing cellulase would generalize to transformants expressing other chemicals requiring or benefiting from greenhouse containment/production, that would be commercially viable. We have made good progress on the generation of transplastomic tobacco lines containing the gene for the high value human protein interleukin-2 (IL2) for CEA evaluation. Although protein expression in the chloroplast does not result in the production of properly glycosylated IL2, there is a market for non-glycosylated IL2. To date, there are no published reports of IL2 production in transplastomic plants.

    Topic 5: Natural ventilation design and control

    9. Improve control strategies as an alternative to existing vent control systems (AZ, NJ).

    No accomplishments during this reporting period.

    10. Continue our efforts to use CFD techniques to evaluate greenhouse natural ventilation systems (AZ, NY, OH, IL).

    Validation of CFD Simulations for Three Dimensional Temperature Distributions of a Naturally Ventilated Multispan Greenhouse obtained by Wind Tunnel Measurement (AZ) As a continuation of the experimental wind tunnel research (Kacira et al., 2007) on the effect of vent configurations on greenhouse ventilation and spatial temperature distributions, the main focus of this study was to compare 3D temperature distributions obtained for different ventilation cases from wind tunnel study with CFD simulations to validate the developed model. Three different turbulence models (standard k-E, RNG and Realizable) were evaluated to determine the effect on the agreement with experimental results. It was found that standard k-E model agreed well with the experimental results. However, the RNG model results were in good agreement with experimental results when the external wind speed was zero m/s (under full buoyancy conditions) in the cases evaluated. The study showed that the selection of the turbulence model was critical depending on the conditions evaluated.

    11. Continue efforts to improve the efficiency and effectiveness of greenhouse fog cooling systems (AZ, IL, NJ, OH, NY).

    Enhanced Climate Control of Semi-arid and Arid Greenhouses Equipped with Fogging Systems (AZ) The primary objective of this project is to develop and validate high-performance control strategies for fogging systems that will enable or improve year-round cultivation in greenhouses located in arid and semi-arid regions. The research includes two main tasks. The first task focuses on the development and validation of climate control algorithms capable of maintaining the air temperature and humidity at levels suitable for crop growth throughout the year. The experiments at the UA-CEAC examines natural ventilation system equipped with variable pressure fogging system using different approaches that take into account the capabilities and limitations of the system. The second task will investigate the influence of the system flexibility on the performance of the fogging system. Operational flexibility will be represented by the number of fogging levels achievable by separate activation of different nozzle lines and/or pressure change in the lines, and the control time-step. To conduct this research, a variable pressure fogging system was installed for the experimental greenhouse. This 300 m2 naturally ventilated greenhouse equipped with both roof and side vents is instrumented with a sensor network enabling 3D scanning of the greenhouse aerial parameters as well as plant parameters (transpiration, leaf temperature) to evaluate the spatial uniformity of interior climate and study plant responses under various conditions. The experiments are in progress to develop the control strategies for the variable pressure fogging system. This project is a collaborative effort with Rafael Linker of Technion and Avraham Arbel of ARO-Volcani Research Center in Israel.

    Impact Statements:
    1. NY completed an energy cost comparison of several imported vs. locally-grown foods. The impending probable shortage of liquid fuels has alerted policy makers and the public that we need to account for the energy needs of agricultural production and the energy costs of bringing food to our tables. The energy budgets which were developed account for both direct energy (such as electricity and fossil fuels) and embodied energy (such as materials, fertilizer, and pesticides).
    2. In AZ a state of the art controlled environment aquaponics research greenhouse was designed and engineered for intensive fish and vegetable production. The research greenhouse has been operating for one year and has established a synergistic relationship between the fish, filtration, and hydroponic plants. Fish effluent is a sustainable and efficient nutrient source for plant production and plant uptake and deposition of nutrients is an environmentally friendly means of filtration.
    3. Subirrigation systems save labor and improve water use efficiency, but salts tend to accumulate in the upper profile of the containers. NY developed fertilizer and electrical conductivity guidelines for nine bedding plant species growing in subirrigation with the goal of optimizing plant growth while reducing the risk of harmful salt accumulation.
    4. CT has developed a Partial Saturation Ebb and Flow irrigation system (PSEF) which allows for more precise water delivery than conventional subirrigation systems. Compared to a conventional subirrigation, plants grown using PSEF used 20 to 30% less water and fertilizer and had enhanced quality characteristics. In one experiment, disease spread was greatly reduced with PSEF. PSEF is now beginning to be adopted on a commercial scale.
    5. As many growers move toward subirrigation systems it has become important to measure container media capillary uptake as opposed to the traditional measurements of aeration and water holding capacity. PA designed and tested a simple method to compare capillary flow in several types of container media. Based on this work, a standard laboratory test should be able to be developed which will permit the characterization of unsaturated water flow in commercial growing media.
    6. AZ used UV-A, blue, green, red, and far-red light-emitting diodes (LEDs), to investigate the effects of different supplemental light qualities on phytochemicals and growth of baby leaf lettuce. The results demonstrated that supplemental light quality could be strategically used to enhance nutritional value and growth of baby leaf lettuce grown under white light.
    7. NY used chloroplast-transformed tobacco cultivars expressing cellulase as a model crop to determine how to produce pharmaceuticals in controlled environments most cost effectively.
    8. NJ completed the installation of a 250 kW landfill gas fired microturbine installation greenhouse facility. The system will generate electricity and heat for the 1-acre greenhouse facility. Excess electricity will be sold back to the local utility grid.
    9. OH constructed a Hydroponic Lettuce Research Laboratory at the Ohio Agricultural and Research Development Center (OARDC) in Wooster, Ohio. Specified combinations of growing media, cultivar, solution flow rate, pH, EC and solution temperature were studied during two experiments. Addition of pH control appears to be responsible for increasing average head weight from 119 grams to 162 grams.
    Last Modified: 18-Aug-2009

    Date of Annual Report: 05/20/2010

    Report Information:
  • Annual Meeting Dates: 03/20/10 to 03/23/10
  • Period the Report Covers: 06/2009 to 03/2010

    • Participants:

    URL: Copy of participant list
    Brief Summary of Minutes of Annual Meeting:

    URL: Copy of minutes
    Accomplishments:
    Topic 1: Energy conservation and alternative energy sources 1. Evaluate biomass derived fuels for greenhouse heating (NE, NJ, NY). NE has been working on biomass heating systems for greenhouses. A grower was asked to measure usage of fuel in hopper tank. The dimension of the hopper and depth of leveled grain was used to calculate the volume of fuel used. Actual burner ON/OFF events and other events such as the ventilation fan operation were logged with the LabVIEW program. The temperature rise over the cold side heat exchanger was continuously logged along with other environmental data and events. Average temperature rises over the cold side varied from 40 to 67 F. Air flow through the exchanger was measured around 1200 cfm, using a traverse of velocity measurements across the air inlet port. Based on calorimetric heat values (app. 6200 Btu/lbm) and bushels of corn burned (app. 0.5 bushels/ hour), the total available energy presented to the burner varied from 151, 090 to 198,418 Btuh. Burner output from average measured air temperature rises in the heat exchanger varied from 95,292 to 156,145 Btuh. Heat loss from the greenhouse was calculated using American Society of Agricultural and Biological Engineering practice (EP406.3), taking into account the inside and outside air temperatures along with incidental ventilation events. Using these methods, the apparent biomass, heating efficiency ranged from %39-68 depending on environmental conditions. A secondary heat recovery exchanger for the biomass burner flue is being considered by the grower, the biomass auger control is being reevaluated.

    NE tests reflective and transmission coefficients for four different colored commercial mulch plastics (white, black, red and dark olive). The greenhouses were fully instrumented to monitor temperature, humidity, and light quantity and quality and energy. White polyethylene (4 mil) gave the best reflectance coefficients and was chosen as the covering for the capillary mats used in the next phase of this study. Forced air furnaces are used in our prototype greenhouse. A polyethylene jet tube from each furnace runs under each of two benches and all heat is supplied in this manner. Total fuel consumption versus set temperatures is being recorded. Project is ongoing.

    NJ, in partnership with other faculty members and a commercial grower, has submitted a proposal to the NE Sun Grant Initiative. The proposal describes a project for the on-farm production of biomass (switchgrass) that, after processing, will be used as a fuel source for greenhouse heating.

    2. Develop decision support systems for alternative fuel heating systems (NJ, NE, NY, PA, CT). NJ started on the development of a decision support system for the operation of a landfill gas fired microturbine delivering electricity and heat to a one-acre research and demonstration greenhouse located near the NJ EcoComplex. A survey was conducted with greenhouse growers in New Jersey to determine how they are coping with rising energy costs and how we can help them compete with this uncertainty.

    PA researched on using unheated high tunnels for bedding plants to determine which plant taxa were sufficiently cold tolerant to be grown in early spring and to evaluate relative marketability , cost of production compared with those produced in a traditional spring heated greenhouse. A stand-alone Quonset greenhouse served as an unheated high tunnel. A computer controlled greenhouse section was set to heating setpoints of 60 NT and 60 DT, served as the comparison. The ventilation setpoints were 70F day and night. Sixteen species of plants, with 50 plants per species for a total of 2,400 plants, were obtained as propagated material. Liners were transplanted into 4 pots with one-half of the plants placed in a 60 NT greenhouse, the other half moved to the unheated high tunnel. The HT was in a protected location on campus, and had a double layer polycarbonate cover which buffered the interior temperature and prevented temperatures from falling below 32°F when ambient outdoor temperatures were in the 20s. Plants grown in the high tunnel took longer to become salable than those grown in the greenhouse, but not all plant taxa responded similarly. The 1st group of plants tolerated the colder temperatures in the high tunnel and was only slightly delayed in development compared to the plants in the heated greenhouse (i.e. Pansy crop). The 2nd group (i.e. snapdragon) were cold tolerant, but displayed a greater delay for the high tunnel plants to become salable. The 3rd group (Verbena) of plants was not very cold tolerant and was delayed substantially by production in the high tunnel compared to production in a heated greenhouse. The low and variable temperatures in the HT increased the crop time to sale for all the crops in the experiment. The delay depended on crop, and varied from 1-2 weeks to 3-4 weeks. Many plants grown in the HT were more compact than those grown at 60 F and this might seem to be an advantage for the consumer since they look more appealing. Many bedding plants grew well, albeit slowly in an unheated high tunnel, there may be potential to use HT as a part of the bedding plant production system in the Northeast and other areas with similar spring climate conditions.

    Topic 2: Water and nutrient solution management 3. Develop protocols for irrigation that maximize water use efficiency while maintaining crop growth and quality (CT, ME, NE, PA, NY, OH, AZ).

    AZ designed developed a machine vision guided system for plant health/growth monitoring. Objective of the study were to develop a methodology using morphological, textural, temporal plant features for the automated non-contact monitoring and to evaluate capability of developed methodology for early detection of tipburn due to calcium deficiency on lettuce. A robotic camera positioning system and an image processing module structured the system. Extracted plant features included Top Projected Canopy Area (TPCA) as a morphology; Red-Green-Blue (RGB), Hue-Saturation-Luminance (HSL) values as color; entropy, energy, contrast, and homogeneity as textural features. The system was capable of extracting listed plant morphological, textural and temporal features autonomously. The developed methodology was capable of identifying the calcium deficient lettuce plants one day prior to the visual stress detection by human vision. Among the extracted plant features TPCA, energy, entropy, and homogeneity showed to be promising markers for timely detection of calcium deficiency in the lettuce crop studied. The future studies will focus on establishing a multi-sensor based plant monitoring platform for resource savings in CE plant production systems.

    AZ continued working with aquaponics system for intensive fish and vegetable production. Research goals of the project include determining the biomass production (fish&plants) that can be achieved per unit of resources (water, nutrients, space), exploring the physiological interactions in the aquaponics system, developing production techniques for large scale applications. The Feed Conversion Ratio is used to measure the production efficiency of fish. Plant biomass and Chlorophyll Concentration Indices are used to determine plant growth and quality. Greenhouse aerial, aquaponics growing variables were monitored/controlled. The complete water chemistry of the system is analyzed biweekly. One year research has established synergistic relationship between the fish component, the filtration component, hydroponic plant component. Current research focused on Tilapia and lettuce.

    AZ has designed and constructed an automated and remotely monitored three floating hydroponic system (FHS) for research. The sustainable management of reduced, reused water and fertilizer in this hydroponic system is being evaluated for production of fresh green salad crops. The automated FHS used LabView for realtime monitoring of EC, pH, dissolved oxygen, nutrient temperature in the root zone, and air temperature, relative humidity, light intensity, CO2 in aerial environment.

    AZ has initiated a new project on soilless strawberry production under semi-arid conditions. The focus includes efficiency of water and fertilizer use. A preliminary data are being collected and a new proposal was submitted to California Strawberry Commission for the possible funding in 2011.

    CT examined a system to rapidly deliver and remove water in ebb and flow watering systems for flooded floors. Less water was absorbed by the root medium and little if any water drains out of the pots. This improved plant quality and prevented spread of disease. Several parameters have been examined varying between this partial saturation ebb and flow watering on a flooded floor compared to full saturation watering. Plants took up 20-30% less water and fertilizer. Biomass until flower development, bloom, stem height, were also reduced by 10-20% under partial saturation. In one experiment with Poinsettia, inoculation of some plants with Pythium resulted in wilting of 20 of 240 non-inoculated plants grown under full saturation. No plants were affected under partial saturation. Post harvest quality of leaves and flowers in a controlled environment were similar under the two watering regimes. Several growers of ornamental potted plants in greenhouses are implementing ebb & flow watering, or increasing the area of production using ebb & flow watering (an increase of about 5 acres in CT in 2009).

    ME, collaborating with the Univ. of Georgia, determined how light, temperature, and relative humidity impact water use of two commercially important greenhouse crops: Petunia and Poinsettia. Substrate water content was maintained at 0.45 L/L for both species, and plants were grown in three different container sizes. The amount of water applied to plants was monitored using a datalogger, and modeling was used to determine the impact of environmental variables on plant water use. Plants grown in larger containers utilized more water throughout the experiment and attained greater biomass. Thus far, models indicate that light appears to be the single greatest factor influencing water use in both species.

    NE conducted research on using capillary mats to water and fertigate a test crop of thirteen strawberry cultivars. From Jan-Apr, plants were grown on two separate benches with capillary mats in 6-inch pots directly on the mat, over 4 mil white polyethylene as a reflectance mulch. Capacitance moisture sensors were calibrated to the potting mix used and installed in two pots at three zones along the cap-mat for a sixty foot run. All pots seemed to be adequately watered in the three zones (40-70% volumetric content). An automatic clock fertigated the mats for a 5 minute event. A single daily watering event was originally programmed for January, but had to be increased in February and March. Seven of 13 cultivars produced strawberries. In addition to total number and berry sizes, nutraceutical properties are being quantified.

    NE studied capacitance moisture sensor to measure volumetric water content in pots growing strawberries in a growth chamber with high pressure sodium and metal halide lights. Photoperiod and temperatures were programmed hourly to match a January day in the greenhouse. A thermodynamic energy balance using leaf temperature allowed estimation of latent heat loss and evapotranspiration. The adaptive model was written in LabVIEW and used a PID module to estimate canopy resistance control. Pot moisture utilization was calculated for two-hour dry down periods and compared with the thermodynamic model. Moisture utilization was within 10% of the latent heat calculation. The thermodynamic model tested in the growth chamber was also used with three zones in the greenhouse and produced similar evapotranspiration numbers. However, the volumetric soil moisture lost in the pots was adjusted for the cap-mat irrigation events.

    NY researched to determine if Si improves the salt tolerance of several floriculture species grown in a soilless peat-based substrate. Initial work was to screen twenty-one floriculture species growing in conventional peat-based substrates for Si accumulation and morphological impacts. All species accumulated measurable levels of Si. Eleven species showed enhanced leaf Si concentration with Si supplementation. Several species exhibited subtle but significant changes in growth parameters, such as increased flower diameter when receiving Si; but morphological effects were not consistently correlated with enhanced Si accumulation. Of twenty-eight floriculture species examined, 40 mM NaCl reduced growth of all but one species. Si enhanced growth of salt stressed plants for twelve species, with a dry weight increase ranging from 47 to 152%. Si did not affect growth of unstressed (0 mM NaCl) plants. Experiments were conducted with Impatiens hawkeri (New Guinea Impatiens) to confirm the Si effects and elucidate mechanisms for salt tolerance. Si mediated salt tolerance was likely a result of several mechanisms. Si enhanced NaCl exclusion by roots and increased cell membrane integrity in leaves of salt stressed plants that had Si. Interestingly, Si reduced expression of three antioxidant enzymes (APX, GR, and MDHAR) in root tissue under salt stress, suggesting there was a reduction in oxidative stress of Si treated plants.

    NY quantified nutrient leaching and growth of Chrysanthemum in response to liquid fertilizer, CRF, or a combination of the two. Leachate nutrient concentration was significantly affected by fertility treatment and production week. When averaged across the entire sampling interval, liquid fed only plants had five times more phosphorus and nitrogen leaching compared to CRF only. Plant dry weight was significantly reduced for plants not receiving any liquid feed; and plant diameter was reduced for treatments receiving less than 6 weeks of liquid feed. When CRF is used as the primary fertilizer source nutrient leaching can be substantially reduced in garden mum production. But, CRF alone appears unable build up initial substrate fertility required by early vigorous growth of chrysanthemums. We attempted to use higher CRF rates to achieve similar size to liquid fed plants. CRF only treatments dramatically reduced leaching, but none were successful in producing comparable plant size/quality as liquid feed. Four weeks of liquid feed followed by only CRF resulted in a three-fold reduction in nutrient leaching and produced a plant comparable in size to liquid only.

    OH has installed Decagon 5TE Volumetric Water Content Sensors randomly in 20 of 200 Austrian pine tree containers in our Landscape Nursery Crop Engineering Laboratory (summer 2009) to test their ability to monitor moisture level, EC and medium temperatures. Four Em50 Decagon Data Loggers were used to record the data. The sensors performed satisfactorily. During summer 2010, a calibration procedure will be developed for these sensors followed by additional testing in container-grown plants. Uncomposted ground pine bark and hard wood chips were evaluated for their physical properties during summer 2009 continuing into winter 2010 as components for container mediums since Canadian Sphagnum Peat Moss has tripled in price during the last several years. Air capacity measurements for a newly formulated mix were 28.3% for 1 gal, 29.5% for 3 gal and 34.6% for 7 gal containers compared to traditional mix measurements of 24.7% for 1 gal, 29.9% for 3 gal and 32.5% for 7 gal containers.

    4. Develop irrigation protocols and filtration or sterilization methods for nutrient solution recirculation that minimize the effects of pathogens or toxic metabolites (CT, NY, OH).

    Topic 3: Sensors and control systems 5. Improve volumetric water content sensor efficacy (ME, NY, OH).

    AZ has been working on physical characterization of a new substrate for automated irrigation management using microtensiometers (MT) on characterizing foam glass, a highly porous substrate and the use of a MT to trigger irrigation, when the matric potential is lower than desired. Experiments with this substrate and stone fibers were conducted resulting in similar yields with 95% confidence interval. Research involved physical characterization of the foam glass with particle size < 1.25 cm and the development of a MT. The MT consists on a pressure transducer, stainless steel tubing, stainless steel porous cap and a solid block of the foam glass. The water movement inside the foam glass growing bag is going to be simulated using Hydrus 3D. The simulation of water flow and irrigation will be manipulated to have ideal scenario to maximize water efficiency. The simulations of irrigations will be tested in a growing bag with mature tomatoes plants in greenhouse.

    NY has developed a risk analysis model to simulate the effects of Pythium phanidermatum on the production of hydroponic baby-leaf spinach under varying nutrient solution temperatures. The simulation suggests that every two degree drop in the nutrient solution temperature approximately halves the frequency of Pythium outbreak within the temperature range of 18 to 24C. Every two day reduction of the amount of time the crop spends in a deep-flow pond approximately halves the frequency of Pythium outbreaks within a crop production range of 12 to 16 days in pond. Production strategies that relied solely on natural light failed rapidly with outbreak frequencies on the order of several per year, in contrast to significantly fewer than a single outbreak per year in the conditions with supplemental lighting, where plants reach harvest weight more rapidly.

    Objective 3 involving the water and nutrient delivery system. 6. Improve sensor control of the greenhouse aerial environment (light, carbon dioxide, temperature, and moisture) (NJ, OH, NY, NE, AZ).

    NE has been using data loggers for monitoring greenhouse and surroundings and campus strawberry houses. Each house was monitored in three measurement zones for air temperature, humidity, total and PAR, plant, floor and potting soil temperature, inside roof glazing temperature. The latter were used to calculate sensible and latent heat exchange rates of the crop with their surroundings and moisture condensation potential on the leaves, floor, and inside glazing throughout each day from early Jan-late Apr. Ventilation fan, unit heater, and biomass burner operations were monitored with non-intrusive, split core current sensors, placed on the appropriate electric supply and control wires. A continuous record and calculation of greenhouse nighttime heat loss and daytime heat gain were calculated using these data and the formulae of the ANSI/American Society of Agricultural and Biological Engineering Standard EP404.3 Heating, Ventilating and Cooling Greenhouse. The loggers communicated with a central computer located in the North end of the house using wireless technology. An additional set of Campbell CR10X battery operated loggers were used for backup and data collected once a week. We also begun operation of a real time, adaptive model which collects the appropriate measurements and calculates the energy and production performance of a greenhouse. The LabView model accounts for heating and ventilation by calculating sensible and latent heat exchanges with the greenhouse and its surroundings. The First Law energy balance includes both short and long wave radiation exchanges with the crop. Entropy production or eternal heat loss verifies integrity of calculations. Model produces estimates of crop water use essential in plant growth and development.Various energy balance solvers are tested. Adaptive model monitors moisture condensation at the leaf surface, interior glazing, and the floor. Moisture condensation and water drip on plant leaves is a primary factor in disease and insect infestation. Greenhouse thermal models are driven by weather data, which is available from the High Plains Automated Weather Station Network for over 150 locations within the region. The objective is making such a system grower friendly and assisting his operation.

    NJ installed sensors and a datalogger in a greenhouse section of the EcoComplex greenhouse that is used for orchid production. Temperature, PAR, relative humidity, wind speed, and wind direction are recorded in an attempt to better characterize the indoor environment. This project is ongoing.

    Topic 4: Environmental effects on plant composition 7. Develop greenhouse design and management protocols to maintain high nutrition values of vegetable crops grown under various environments (AZ, CT, NJ).

    AK has been conducting research to determine the potential for LED greenhouse lighting. Production greenhouses at high latitudes have a large demand for supplemental lighting. More energy efficient lighting technologies have a large impact on economics of year round greenhouse operations. Panels (300 W) with red LEDs supplemented with 10 percent blue LEDs (peak emission at 456 nm), tri-band LEDs with 40 percent red (660 nm), 40 percent orange-red (630 nm) and 20 percent blue (460 nm), and white LEDs are tested in a controlled environment production area. Lettuce and Rudbeckia hirta 'Toto' are grown below the LED panels and as a comparison under high-pressure sodium, metal halide and 5T fluorescent lamps. PAR at plant height was 150 umol/m2/s1 for all lamp types. An LI-6400 photosynthesis system with a clear top leaf chamber is used to measure net photosynthetic rate(Pn) . Measurements are made on exposed single leaves at 400 ppm CO2. Pn are in the range of 3.5 to 4.0 umol CO2 m2/s-1 independent of lamp type suggesting PAR to be more important for rate of Pn than the spectral energy distribution.

    AZ completed several experiments toward applications of LEDs in greenhouse plant production. Among them, the experiments conducted during 2008-2009 were for testing supplemental lighting quality (UV, blue, green, red, and farred) for their effects on bioactive compounds of leaf lettuce. Anthocyanins concentration increased by 11% and 31% with supplemental UV-A and blue respectively, carotenoids concentration increased by 12% with supplemental blue, phenolics concentration increased by 6% with supplemental red while supplemental farred decreased anthocyanins, carotenoids and chlorophyll concentration by 40%, 11% and 14%, respectively, compared to those under in the white light control.

    8. Develop greenhouse design and management protocols to maximize production of beneficial compounds such as phytochemicals and biopharmaceuticals (NY, AZ, CT, MI, NJ).

    MI tested biopesticides, reduced-risk products, experimentals, and industry standards for control of oomycetes with greenhouses trials. The biopesticide, Reynoutria sachalinensis, extract of giant knotweed (Regalia SC), significantly reduced downy mildew infection of coleus leaves, while it was less effective than reduced-risk products (azoxystrobin, mandipropamid, fenamidone, mefenoxam), experimental BAS 651F (dimethomorph + ametoctradin) and standards (fluoxastrobin, dimethomorph). Biopesticides, Gliocladium virens (SoilGard 12G), Bacillus subtilis (Companion), Streptomyces lydicus (Actinovate) and Trichoderma harzianum (RootShield), were compared with standards etridiazole (Truban 30WP), dimethomorph and reduced-risk mefenoxam for control of oomycetes (Pythium spp., Phytophthora drechsleri and Phytophthora nicotianae) on calibrachoa and verbena. Etridiazole, dimethomorph and mefenoxam performed significantly better the inoculated controls in all trials. Streptomyces lydicus combined with etridiazole was especially effective in all trials and prevented death due to Pythium spp. on calibrachoa and verbena, P. drechsleri on calibrachoa, and limited death due to P. nicotianae on verbena to 16.7%. Other biopesticide treatments which prevented plant death were Gliocladium virens (Pythium on calibrachoa), Trichoderma harzianum (Pythium on calibrachoa), and Streptomyces lydicus (P. drechsleri on calibrachoa). Biopesticide treatments which were significantly better than the control included Gliocladium virens for P. nicotianae on verbena, and Bacillus subtilis for Pythium on verbena and calibrachoa and P. nicotianae on verbena. The biopesticide, Reynoutria sachalinensis, significantly reduced downy mildew infection of cucumber leaves, although not as effectively as propamocarb (Previcur Flex 6SEC) or reduced-risk cyazofamid (Ranman) or fluopicolide (Presidio 4SC) all tank-mixed with chlorothalonil (Bravo Weather Stik 6SC). Airborne sporangial concentrations were positively related to average temperature and negatively correlated with both average relative humidity and leaf wetness at all of the sites monitored in 2008 and 2009. Rainfall was not significantly correlated with sporangial concentrations at any of the sites monitored in 2009, but it was positively related to sporangial concentrations at the Monroe County site in 2008. The concentrations of airborne sporangia showed a marked diurnal periodicity with the highest concentrations between 0800 and 1300 hours and a pronounced peak at about 1000 hours.

    NY has been working on environmental control to increase genetic expression of valuable chemicals in tobacco. Research has been nearly completed to quantify effects of environmental control on the production of a useful industrial enzyme, using extractions from hydroponically-grown and genetically-modified tobacco (chloroplast transform). The effect of plant spacing on biomass yield and target enzyme output indicated that maximum productivity of target enzyme, measured as mass per unit area per unit time, can be achieved in a range of final plant spacing. The best plant spacing appears to fall in the middle of the range examined, near 1ft2/plant. Plants are unable to take full advantage of additional space when flowering commences, as leaf growth is curtailed. Tobacco grows very slowly in absolute terms during the first three weeks since the seed starts out so small, and for this reason harvest of seedling sized plants for biomass is also a dubious proposition.

    AZ continuously seeks for funding in this area (biopharmaceutical production in greenhouse using transgenic crops). However, during the reporting period, AZ could not secure the fund and therefore no activities under this project area, unfortunately. )

    Topic 5: Natural ventilation design and control 9. Improve control strategies as an alternative to existing vent control systems (AZ, NJ).

    10. Continue our efforts to use CFD techniques to evaluate greenhouse natural ventilation systems (AZ, NY, OH, IL).

    AZ continued CFD modeling to evaluate various side/roof vent configurations, compared the results with a set of previous experiments conducted in a wind tunnel with naturally ventilated multi-span greenhouse with scaled models. The study compared three dimensional temperature distributions obtained for different ventilation cases from wind tunnel study with CFD simulations to validate the model. A satisfactory quantitative agreement was found for vertical and horizontal temperature distribution between the experimental and simulation results. Thus, two new turbulence models were used checking the effect on the agreement with experimental results to have a better knowledge of the simulations set up for future validations. AZ continues to actively involve in organization of CFD sessions in related conferences, the next ISHS CFD Working group technical sessions are scheduled for GreenSys2011, July, Greece.

    11. Continue efforts to improve the efficiency and effectiveness of greenhouse fog cooling systems (AZ, IL, NJ, OH, NY).

    AZ continued on developing climate control strategies for a naturally ventilated greenhouse equipped with variable high pressure fogging system. The cooling demand inside the greenhouse varies during day/seasons. Thus, it may be advantageous using variable pressure fogging (VPF) system, where specific fog rates can be supplied based on the cooling demand. But, absence of effective cooling strategies is limiting extensive use of the system. A computer simulation was developed to compare a proposed control algorithm for VPF to a typical on/off fixed pressure fogging system based on vapor pressure deficit (VPD). Results showed that VPD based fixed pressure fogging strategy consumed more water and energy compared to the VPF system. Cycling of the pump was smaller and higher stability of temperature and relative humidity were achieved by the operation of the VPF system.

    Other accomplishments that do not necessarily relate to the 2008-2013 NE 1035 Multistate Research Project objectives: NJ, a new course Energy Technology and its Environmental Impact was developed and taught. This 300-level course was developed around the textbook written by F.M. Vanek and L.D. Albright titled Energy Systems Engineering: Evaluation and Implementation. Studies are ongoing for the 250 kW microturbine installation at the EcoComplex greenhouse. The system has been operational intermittently due to unforeseen maintenance and repair issues. Some electricity was generated and used on-site and the remainder exported to the local electric grid.

    NY compared single and double seeding for baby-leaf spinach production in deep-flow ponds. The objective was to facilitate scaling up from bench-scale spinach production to commercial-greenhouse-scale production. In the commercial-scale-up project, 48 standard 338-cell Seedling trays (each 13.5 inches by 26.5 inches in horizontal dimensions, 1.75 inches high) were seeded weekly, germinated for three days in a growth chamber, and placed in one of two ponds and grown for 12 to 14 days. These experiments demonstrated no yield difference between single seeding all cells and double-seeding half the cells. Double-seeding, while maintaining the same plant density, is recommended when using 1 ¾ inch high cells of the type used in these experiments. This halves the amount of medium needed. However, reusing root medium from spinach production proved not to be a viable option to save resources, for the root disease, Pythium aphanidermatum, remained viable in the recycled and heat-treated medium, leading to disease outbreaks in subsequent crops.

    NY Most floriculture crops are sensitive to ethylene, an odorless, colorless gas produced naturally by plant materials or by incomplete combustion of heating fuels and engine exhaust. We conducted experiments on chronic ethylene effects on 30 bedding plant species. Results from the first year indicate that flowering was variably inhibited by 10 or 50 ppb ethylene for most species, though some eventually recovered from the effect. Where flowering did occur in ethylenes presence, flower size was reduced and flower senescence was more rapid compared to control. In general, 10-50 ppb ethylene was a growth inhibitor for most species, while for others it encouraged branching and growth. These results lend support to the hypothesis that ethylene response, whether growth promotion or inhibition, can be incorporated into a single concentration dependent biphasic response model.

    OH worked on a new design for insect scouting for greenhouses. Scouting is the backbone of all integrated pest management program. Timely, accurate insect pest population estimates and spatial variability information can reduce the number of pesticide applications by 30 to 60%. As the manual scouting process is laborious and time consuming, and performance of passive insect collection methods are often affected by temperature, we initiated an effort to develop a high efficiency insect collection prototype for greenhouse applications. A suction device, and a yellow sticky tape mounted on a traveling boom were evaluated for the insect collection task. Greenhouse tests were conducted to evaluate the collection efficiency of a conventional scouting method (i.e. stationary sticky card) and two prototyped mobile scouting methods under two greenhouse temperatures. The vacuum-based approach was found most reliable. It resulted in the same collection efficiency while collecting adult whiteflies from poinsettia plants for two different temperatures: 13.5 and 28.5 C.

    OH continued to work on nutrient film technique (NFT) for lettuce. Results from a series of four designed experiments indicate choice of growing cube composition has a marked impact on yields (or conversely growing time) when using NFT for hydroponically-grown lettuce crops. Rock wool growing cubes are currently used most frequently by hydroponic lettuce growers and is an industry standard. Lettuce grown in a new plastic fiber growing cube yielded 29% less mass (wb) than rock wool in Autumn 2008 (Experiment No. 1) and 34% less in Spring 2009 (Experiment No. 2). However, for Experiments No. 3 and 4 (Summer, 2009), lettuce grown in coconut core cubes and a commercially available mix of peat moss, perlite and vermiculite (Oasis fertis) cubes yielded 19% and 14% more lettuce, respectively, than rock wool. Purpose for research is to develop/demonstrate economically sustainable, year-round, high quality, hydroponic crop production systems operating in energy efficient greenhouses.

    Impact Statements:
    1. NE worked on biomass heating systems for greenhouses.A system was developed for determining usage of fuel in hopper tank continuously. Methodologies were developed to determine apparent biomass and heating efficiencies based on environmental conditions. A heat recovery exchanger for the biomass burner flue is being considered and a biomass auger control is being evaluated. NJ is developing decision support system for landfill gas fired microturbine delivering electricity, heating one-acre research greenhouse.
    2. AZ developed a machine vision guided system for plant health/growth monitoring. The system was capable of extracting plant morphological, textural and temporal features autonomously. The developed methodology was capable of identifying the calcium deficient lettuce plants one day prior to the visual stress detection by human vision. The capability of the system is being improved with multi sensor based sensing platform for crop quality, growth monitoring and establish resource use savings in controlled environment crop production systems.
    3. ME determined how light, temperature, and relative humidity impact water use of two commercially important greenhouse crops: Petunia and Poinsettia. Plants grown in larger containers utilized more water and attained greater biomass. Developed models indicate that light appears to be the single greatest factor influencing water use in both species. CT examined partial saturation ebb and flow watering on a flooded floor compared to full saturation watering. No plants were affected under partial saturation. Post harvest quality of leaves and flowers were similar under two watering regimes.
    4. NY researched to determine if Si improves the salt tolerance of several floriculture species grown in a soilless peat-based substrate. Eleven species showed enhanced leaf Si concentration with Si supplementation. Some species exhibited subtle changes in growth parameters, such as increased flower diameter when receiving Si; but morphological effects were not consistently correlated with enhanced Si accumulation. Si enhanced growth of salt stressed plants for twelve species, with a dry weight increase ranging from 47 to 152%. Si did not affect growth of unstressed plants.
    5. AZ developed microtensiometers (MT) to characterize foam glass, a highly porous substrate and the use of a MT to trigger irrigation.
    6. NY has developed a risk analysis model to simulate the effects of Pythium phanidermatum on the production of hydroponic baby-leaf spinach under varying nutrient solution temperatures. The simulation suggests that every two degree drop in the nutrient solution temperature approximately halves the frequency of Pythium outbreak within the temperature range of 18 to 24C.
    7. AK is determining the potential for LED greenhouse lighting. Production greenhouses at high latitudes have a large demand for supplemental lighting. More energy efficient lighting technologies have a large impact on economics of year round greenhouse operations. Measurements are made on exposed single leaves to determine net photosynthetic rate (Pn). Measurements ranged from 3.5 to 4.0 umol CO2 m2/s-1 independent of lamp type suggesting PAR to be more important for rate of Pn than the spectral energy distribution.
    8. AZ completed several experiments toward applications of LEDs in greenhouse plant production. Anthocyanins concentration increased by 11% and 31% with supplemental UV-A and blue respectively, carotenoids concentration increased by 12% with supplemental blue, phenolics concentration increased by 6% with supplemental red while supplemental farred decreased anthocyanins, carotenoids and chlorophyll concentration by 40%, 11% and 14%, respectively, compared to those under in the white light control.
    9. MI tested biopesticides, reduced-risk products, experimentals, and industry standards for control of oomycetes with greenhouses trials. The biopesticide, Reynoutria sachalinensis, extract of giant knotweed (Regalia SC), significantly reduced downy mildew infection of coleus leaves, while it was less effective than reduced-risk products (azoxystrobin, mandipropamid, fenamidone, mefenoxam), experimental BAS 651F (dimethomorph + ametoctradin) and standards (fluoxastrobin, dimethomorph).
    10. NY has been working on environmental control to increase genetic expression of valuable chemicals in tobacco. The effect of plant spacing on biomass yield and target enzyme output indicated that maximum productivity of target enzyme, measured as mass per unit area per unit time, can be achieved in a range of final plant spacing. The best plant spacing appears to fall in the middle of the range examined, near 1ft2/plant. Plants are unable to take full advantage of additional space when flowering commences, as leaf growth is curtailed.
    11. AZ developed CFD modeling to evaluate the effect of various side/roof vent configurations on vertical and horizontal temperature distributions in a naturally ventilated greenhouses. Satisfactory quantitative agreement was found for vertical and horizontal temperature distribution between the experimental and simulation results. Two new turbulence models were evaluated. A climate control strategies for a naturally ventilated greenhouse equipped with variable high pressure fogging system has been ongoing to evaluate water and energy savings.
    12. OH continued to work on nutrient film technique (NFT) for lettuce. Results from a series of four designed experiments indicate choice of growing cube composition has a marked impact on yields (or conversely growing time) when using NFT for hydroponically-grown lettuce crops. Lettuce grown in coconut core cubes and a commercially available mix of peat moss, perlite and vermiculite (Oasis fertis) cubes yielded 19% and 14% more lettuce, respectively, than rock wool.
    13. OH developed a new design for insect scouting for greenhouses using a suction device and a yellow sticky tape mounted on a traveling boom. Greenhouse tests showed that the new design was found most reliable compared to conventional scouting method using stationary sticky card. It resulted in the same collection efficiency while collecting adult whiteflies from poinsettia plants for two different temperatures: 13.5 and 28.5 C.
    14. NY quantified nutrient leaching and growth of Chrysanthemum in response to liquid fertilizer, CRF, or a combination of the two. Leachate nutrient concentration was significantly affected by fertility treatment and production week. Plant dry weight was significantly reduced for plants not receiving any liquid feed; and plant diameter was reduced for treatments receiving less than 6 weeks of liquid feed. When CRF is used as the primary fertilizer source nutrient leaching can be substantially reduced in garden mum production. But, CRF alone appears unable build up initial substrate fertility required by early vigorous growth of chrysanthemums.
    Last Modified: 24-May-2010

    Date of Annual Report: 09/20/2011

    Report Information:
  • Annual Meeting Dates: 06/20/11 to 06/22/11
  • Period the Report Covers: 03/2010 to 05/2011

    • Participants:

    URL: Copy of participant list
    Brief Summary of Minutes of Annual Meeting:

    URL: Copy of minutes
    Accomplishments:
    Topic 1: Energy conservation and alternative energy sources

    1. Evaluate biomass derived fuels for greenhouse heating (NE, NJ, NY).

    NE tested different biomass fuels for greenhouse heating, including: whole shelled corn, dry distillers grains pelletized, wood pellets and blends between each biomass. Bomb calorimetry tests were performed on each biomass fuel and their respective ash residue obtained from an actual field burner test. Furnace and heat exchanger efficiency and cost effectiveness for each fuel type was determined. Emissions data was measured for each fuel including: carbon monoxide, carbon dioxide, nitrous oxides, sulfuric oxides, and particulate matter. A commercial biomass furnace was used for a greenhouse at Firth, Nebraska and compared to a propane furnace. The biomass furnace generally had a lower efficiency than the 81 percent, advertised for the propane furnace. Biomass furnace efficiencies typically ranged between 50 and 80 percent. During the four year study period (2008-2011),cost savings using biomass fuels ranged between 30 and 60 percent totaling over $15,000, when compared to propane. Biomass fuels were found competitive, cost effective, and sustainable when compared to propane. However, at typical natural gas rates, natural gas will be more cost effective. In rural greenhouses this is not an issue due to the inability to utilize natural gas. A grower should watch market prices and buy in bulk when costs are cheapest, specifically during non heating seasons if possible.

    NE collected air emission samples for four biomass fuels. These results were statistically analyzed and determined to be significant. These tests provide more understanding into biomass emissions, although they are furnace specific. The statistical analysis confirmed the hypothesis that emissions increased with increased combustion temperature, and that corn and corn blends will emit more NOx and SOx than wood pellets.

    2. Develop decision support systems for alternative fuel heating systems (NJ, NE, NY, PA, CT).

    NJ: a PhD student (Ariel Martin) continues to develop a decision support system for the operation of a landfill gas fired microturbine system that delivers electricity and heat to a one-acre research and demonstration greenhouse located near the NJ EcoComplex.

    NE, working with a commercial greenhouse cooperator at Firth, David Mabie (graduate student) developed the prototype LabVIEW® (National Instruments, Austin, TX) fuzzy logic greenhouse air temperature control system. LabVIEW was also used for a greenhouse heat loss calculator virtual instrument (VI). The heat loss calculator was based on the American Society of Agricultural and Biological Engineering (ASABE) Engineering Practice (EP406.3). The program estimates the total heat loss for each wall and the floor of the greenhouse with a final computation the total heat loss. A major advantage of using LabVIEW is the integration of simulation with hardware instrumentation and control. During the 2009 and 2010 production seasons, the grower kept a detailed record of both biomass and propane usage. Biomass usage in the feed hopper tank was measured volumetrically to determine the use of fuel. The burner control and the ventilation fan operation events were logged with a LabVIEW program, described in previous progress reports. The temperature rise over the cold side heat exchanger of the biomass furnace was also continuously logged along with the greenhouse environmental data. In 2010, the growers cooling system was reduced to one ventilation fan, because of an electrical problem. The greenhouse was therefore kept more of a closed condition. The greenhouse temperature was cycled between around 20°C at night and 24-25 °C during the day. The 2010 burn efficiency calculations were similar to the 2009 results. During the 2010 period, the biomass burner was able to meet steadily the 160 to 180 thousand Btuh heat loss rate of the greenhouse to maintain the desired air temperatures. There was about 26% cost savings for the heating season and a 48% savings, comparing biomass to propane during a 6-8 week growing period. One problem during low heat demand was overheating of the greenhouse, when the biomass system was left running. Another difficulty was to manually re-fire the biomass system every evening (labor and start up fuel). An automatic ignition would be preferred. A secondary heat recovery exchanger for the biomass burner flue is still being considered by the grower for improved efficiency. Overall, the grower was quite pleased with the operation.

    ME has been collaborating with Georgia to develop a model that predicts plant water use in greenhouses based on environmental conditions. To develop the model, a capacitance sensor automated irrigation system is used to maintain plants at constant and high volumetric water contents (q = 0.40 L"L-1). Concurrently, light, temperature, and vapor pressure deficit are monitored. Regression analysis is used to develop the model. Previous research (Kim et al., 2011) indicated that light was the most important variable driving plant water use in greenhouses, particularly in Georgia. However, in a study conducted in the fall in Maine, light did not significantly impact water use of the shade tolerant plants Heuchera Palace Purple and Mint Frost. Vapor pressure deficit was the strongest factor impacting plant water uptake. It seems that more research should be conducted to strengthen our model.

    Topic 2: Water and nutrient solution management

    3. Develop protocols for irrigation that maximize water use efficiency while maintaining crop growth and quality (CT, ME, NE, PA, NY, OH, AZ). NE used capillary Mat (CapMat, Phytotronics, Inc, Earth City, MO USA) to water and fertigate a winter strawberry, cultivar, production study in a UNL East campus Quonset greenhouse. Plants were grown on two separate 6 ft by 60 ft benches with CapMats from January through April. Six-inch pots were interfaced with the CapMat fabric, along with 4 mil white polyethylene as a reflective mulch and vapor barrier. CapMats were wetted using twin wall tubing installed under the capillary fabric. A special jig device was developed to allow pots to access the fabric through the polyethylene mulch. Individual flag pots of strawberries were monitored with capacitance moisture sensors (Decagon Devices, Inc. Pullman, WA), calibrated to the potting mix formula, and installed at three zone locations (north, middle, and south) over the sixty foot length of each bench. An automatic clock typically fertigated the CapMats on selected time event schedules. However, the daily watering event had to be adjusted according to crop and environmental conditions to minimize night time humidity levels and to reduce plant disease and pest pressure. An electronic meter was used to measure greenhouse water use during the growing period. The pots were adequately watered at the three zones (50-60% volumetric content). An electronic gas meter was used to monitor natural gas use. Furnace and ventilation events controlled by a Groton II system (ACME Engineering and Manufacturing, inc., Muskogee, OK) were also monitored using electronic split core, current sensors and LabVIEW programming. The strawberry cultivar study was conducted during both 2010 and 2011, and is expected to continue in 2012. Stomatal canopy resistance was simulated, as a LabVIEW control variable for the strawberries grown in an East Campus Greenhouse and CapMat fertigation system. An adaptive, real-time dynamic energy model (VI) based on the First and Second Laws of Thermodynamics and psychrometrics accounted for canopy entropy production, net radiation, sensible and latent heat exchanges for the strawberries. Measured canopy TLeaf and air temperatures Tair, relative humidity fair, and radiation data were transmitted wirelessly from three bench zone locations to a host computer, using sensors and National Instruments LabVIEW® software. Stomatal resistance (rLeaf - s/m) was simulated as a LabVIEW Proportional Integral Differential (PID) controller (subVI) in order to balance net energy for the canopy. Latent results compared favorably from draw-down pot moisture contents, measured with the capacitance sensors.

    OH used an Argus Nutrient Delivery System to deliver water and nutrients to 488 trees during the 2010 summer growing season. The system was custom designed and constructed to accurately and precisely deliver nutrient solutions during short irrigation events (5 to 10 min) in small volumes (10 to 50 L) to container-grown plants typically required for treatments in research plots. Five nutrient treatments were specified and delivered to 200 Austrian pine (Pinus nigra) trees after which the trees will be subjected to canker and insect induction summer 2011. In a second project, 180 trees were grown using three nutrient treatments to determine the effects of imidacloprid application and fertilization regimes in the nursery on subsequent establishment, growth, stress tolerance, and rates of carbon sequestration of common shade trees Homestead elm (Ulmus × Homestead) and Heritage river birch (Betula nigra) after transplanting to an urban street right-of-way in the Wooster, Ohio. Finally, 108 trees were grown for a third project that was designed to determine the effect of fertility and sugar (sucrose) application on the concentration of carbon, nitrogen, condensed tannins and phenolics (secondary metabolites) in hybrid poplar trees (Populus nigra clone 5271) and the photosynthetic rates and overall growth of the trees. For the first time, the nutrient delivery system successfully controlled pH for all treatments to a specified set point of 6.0 (+/- 5%) using a dilute sulfuric acid solution.

    4. Develop irrigation protocols and filtration or sterilization methods for nutrient solution recirculation that minimize the effects of pathogens or toxic metabolites (CT, NY, OH).

    NY: Pythium aphanadermatum zoospores reproduce more slowly as hydroponic solution temperature decreases. This is especially important with spinach production, for spinach is particularly sensitive to the disease. Experiments showed there was no significant difference between the final harvest fresh weights of the spinach plants grown with a root zone temperature of 15 C and those of plants grown with a root zone temperature of 20 C. Moreover, there was no significant difference between the leaf areas of plants grown under the two, suggesting that lowering the root temperature to 15 C may provide/allow for greater disease control or a longer spinach crop cycle without losing productivity or changing the appearance of the product. Chilling nutrient solution in a floating hydroponic system required relatively little energy due to the presence of insulating rafts between the solution and the greenhouse environment, used to hold the plants.

    NY: Worldwide, greenhouse operations face increasing pressure to reduce irrigation demands and/or use poorer quality (high salinity) irrigation water. Led by graduate student, Gonzalo Villarino, we have addressed short term needs by developing salt management guidelines (i.e. threshold levels) for several common floriculture species. Results of this effort were published as a two article series in Greenhouse Grower Magazine and are in press in the journal HortTechnology. We are also using molecular techniques to learn more about processes that plants use to mitigate salt toxicity. The naturally occurring sugar, trehalose, has been found to enhance salt and drought tolerance of several crops when precursors to its formation (TPS and TPP) are over-expressed. However it is not well understood if this is due to trehalose acting as an osmoprotectant or rather due to signaling and metabolic responses. We are using a combination gene silencing/overexpression approach using Petunia as a model species to elucidate the role of the trehalose pathway in abiotic stress tolerance.

    CT: Using recycled nutrient solution to water plants is the preferred legislative solution to prevent groundwater pollution from intensive agricultural production. Several potential problems may arise from recycled nutrient solutions to produce vegetable crops. Accumulation or deficiency of elements in nutrient solutions could have deleterious effects on plant growth, product quality, and the dietary value of vegetables. We examined the composition of a nutrient solution as it was periodically recycled to a greenhouse tomato crop (Solanum lycopersicon L.), in comparison to solutions that were used to water plants only once. Crops were grown in spring and summer in a greenhouse using rock-wool as the root medium. The transition from vegetative to fruit growth, and from cool to warm weather, resulted in a decreased demand for nitrate, and other nutrients, and an increase in electric conductivity of water drained from the root zone. These changes were greater for recycle than discharge systems, and the recycle treatment took longer to return to an optimal composition. There were no consistent effects on yield, and little difference in composition of fruit or vegetative tissue, despite the large but temporary variation in composition of the nutrient solution due to recycling. Outcomes: Information was conveyed to commercial growers via by conversations at growers meeting in Connecticut, at the experimental farm, and at their commercial operations. The general public was informed of the results through demonstrations and displays at the public open house at our experimental farm. Recirculation reduces the amount of fertilizer used to grow crops and it avoids the discharge of nutrient solution to aquifers or to treatments facilities. Recirculation can be used by the more than 50 greenhouse vegetable growers in Connecticut, only if this process does not lead to poor yield, spread of disease, or an imbalance in nutrients. So far, this refinement has been adopted by growers who produce lettuce in hydroponics, but not by growers who produce tomato crops.

    OH: a Controlled Nutrient Delivery System (CNDS) designed by Bauerle continued to successfully inject essential plant nutrients at specified recipes for optimization of plant growth at a large commercial nursery. Chlorine dioxide was used in a water cleansing system to control plant pathogens in recycled effluent water. The recycled effluent was ponded with fresh water from Lake Erie. These ponds provided source water for the nurserys irrigation system. The pH of this ponded water was monitored and recorded every 5 min during the 2010 summer growing season. Even though these measurements ranged from a pH=7.5 to pH=9.5, the CNDS was capable of delivering water and nutrients to a targeted pH=6.5 thus assuring continuous availability of major and minor elements to the plants throughout the growing season.

    Topic 3: Sensors and control systems

    5. Improve volumetric water content sensor efficacy (ME, NY, OH). During summer 2010 OH continued a cooperative project with Willoway Nurseries, Inc. that was initiated summer 2008. Decagon 5TE Volumetric Water Content Sensors were randomly installed in four 400 tree plots (five sensors per plot) at Willoway Nurseries in Avon Lake, Ohio, summer 2010, to test their ability to monitor moisture level, EC and potting medium temperatures. Four Em50 Decagon Data Loggers were installed to record the data. A lap-top computer was used to download the data from the Em50 data loggers in the field. A continuously recording pH sensor was also installed (Spring 2010) and used to record diurnal variations of pH in a pond used to store recycled nutrient solutions at Willoway. Analysis of the data is pending.

    6. Improve sensor control of the greenhouse aerial environment (light, carbon dioxide, temperature, and moisture) (NJ, OH, NY, NE, AZ).

    Sensors and a datalogger were used in a greenhouse section of the EcoComplex greenhouse that is used for orchid production. Temperature, PAR, relative humidity, wind speed, and wind direction are recorded in an attempt to better characterize the indoor environment. This project is ongoing. NY has fabricated and installed a beta version of a Daily Light Integral (DLI) controller in a commercial greenhouse in Ontario, Canada. The controller implements the DLI control algorithm patented by Cornell. Operation of the DLI controller will be monitored and quantified for one year. Other sites are being investigated currently to provide a range of climate and solar conditions for beta tests.

    NE developed and successfully tested a LabVIEW instrumentation and adaptive canopy energy balance model for collecting crop and environmental data to assess energy utilization, moisture condensation potential, and production performance within the greenhouse. Zone loggers communicated with a master computer using wireless technology. A system was operated with a biomass heated greenhouse at Firth, NE. Weather, greenhouse environment, and crop canopy were monitored every ten minutes. A fuzzy logic controller was also integrated for improved biomass furnace control. Adaptive energy model responses including pot-canopy water use could be viewed over the internet. Both the Firth cooperator greenhouse environment and surroundings and Campus strawberry houses were monitored at 10-minute intervals, 24-hours per day by a set of data loggers. Each house was divided into three measurement zones for air temperature and humidity, total and photosynthetically active radiation (PAR), plant temperature, floor temperature, potting soil temperature, and inside roof glazing temperature. Data was used to calculate the current sensible and latent heat exchange rates of the crop with their surroundings and moisture condensation potential on the leaves, floor, and inside glazing throughout each day from early January to late April. Outside air temperature, total solar radiation, and wind speed were also measured, but backed up with hourly data from Lincoln supplied by the High Plains Automated Weather Data Network. Ventilation fan, unit heater, and biomass burner operations are monitored with non-intrusive, split core current sensors, placed on the appropriate electric supply and control wires. A continuous record and calculation of greenhouse nighttime heat loss and daytime heat gain was obtained. OH conducted data analysis to evaluate a model as a part of establishing a user friendly interface that will allow a decision support tool to be used for general exploration. The tool can be used to analyze cooling requirements or the heat harvesting potential of user specified greenhouses by providing information such as greenhouse structural design, local weather information, and desired temperature set points.

    Topic 4: Environmental effects on plant composition

    7. Develop greenhouse design and management protocols to maintain high nutrition values of vegetable crops grown under various environments (AZ, CT, NJ).

    CT: Composition of hydroponic lettuce: Effect of time of day, plant size, and season. Background: The diurnal variation of nitrate and sugars in leafy green vegetables may vary with plant size or the ability of plants to buffer the uptake, synthesis, and use of metabolites. Bibb lettuce was grown in hydroponics in a greenhouse and sampled at 3-hour intervals throughout one day in August 2007 and another day in November 2008 to determine fresh weight, dry matter, and concentration of nitrate and sugars. Plantings differing in size and age were sampled on each date. Results: The dry/fresh weight ratio increased during the daylight period. This increase was greater for small compared to large plants. On a fresh weight basis, tissue nitrate of small plants was only half that for larger plants. The variation in concentration with time was much less for nitrate than for soluble sugars. Soluble sugars were similar for all plant sizes early in the day, but they increased far more for small compared to large plants in the long days of summer. Conclusions: The diurnal variations of nitrate and sugars were not complementary. Delaying harvest to later in the day would increase dry matter and sugar concentration, but it would have little effect on nitrate. Outcomes: Several growers have started producing salad greens in greenhouses and high tunnels, and lettuce in hydroponics. In part this is due to information developed by this project and previous projects on this subject.

    NE conducted a greenhouse, winter-time strawberry cultivar and production management study in 2011. Strawberry nutraceutical data (spring 2010) indicated a consistent range in total phenols (1.06 -1.84 mg /g). Nine of the cultivars showed significant differences when compared to the very lowest level. Similar results occurred with total flavonoids (0.28-0.62 mg/g). The antioxidant capacity study showed significant difference in varieties with Strawberry Festival and Darselect (73-75 uM/g) having more antioxidant capacity than Honeoye, Albion and AC Wendy (32-49 uM/g). Additional biochemical results for 2010 and 2011 winter grown, strawberries are currently not available for this report. The best producing strawberry cultivars - Fall/Winter 2010-2011 production peaked during the weeks of December 4 and 11, and included Albion, Chandler, Darselect, Clancy and Seascape which produced the largest amount of total berry mass and numbers. Water and natural gas usage for 2011 was 43 gal and 1920 ft3, respectively. Data from the Spring 2010 study showed that the sugar concentration and sweetness index were highest in the cultivars Albion and AC Wendy. Unfortunately these are also the cultivars with the lowest anti-oxidant capacity. Other high sugar cultivars included Strawberry Festival, Honeoye, Seascape and Dar-Select. We are waiting for the Spring 2011 results before final selection of the cultivars for 2011-2012. Preliminary start-up costs estimates. Using a selected greenhouse company as a source it appears that a 25-ft x 75-ft double poly greenhouse, with low-cost benching would cost between: $20,000-$35,000. Other companies have been contacted to provide alternative prices. Time-motion studies are underway to determine labor costs for winter-time strawberry production in Nebraska. The project has also been tracking consumer strawberry prices at traditional food markets to determine times for peak retail pricing.

    8. Develop greenhouse design and management protocols to maximize production of beneficial compounds such as phytochemicals and biopharmaceuticals (NY, AZ, CT, MI, NJ).

    MI: Oomycete pathogens cause significant losses in greenhouse and field ornamental and vegetable operations, and have developed resistance to control products. Oomycetes can persist for long periods of time in soil and/or plant material, and be present in irrigation water sources. Nine replicated efficacy trials with 95 treatments tested 33 products in the greenhouse and field for oomycete control. The greenhouse plant activator product, A9180A, prevented downy mildew on coleus when applied alone (0.25, 0.5 or 0.75 oz/100 gal) or tankmixed (0.5 oz + azoxystrobin 4 oz/100 gal) as a spray 10 and 3 days before inoculation (DBI). It was equally effective as a drench applied alone (0.25 oz or 0.9 oz) or tankmixed (0.25 oz + azoxystrobin 0.9 oz) 17DBI. Fluopicolide performed well in 7 trials. In the greenhouse, fluopicolide prevented basil downy mildew (1 foliar spray, 2 fl oz), geranium death due to Pythium ultimum (2 drenches, 4 fl oz), and significantly limited root rot disease of osteospermum due to Phytophthora drechsleri (2 drenches, 14 fl oz). Foliar sprays at 5-10-day intervals of fluopicolide (0.19, 0.25 pt), fluopicolide (0.25 pt) tankmixed with chlorothalonil (2 pt), and fluopicolide (0.25 pt) tankmixed with chlorothalonil (2 pt) and alternated with other products were especially effective at managing cucumber downy mildew in the field; fluopicolide (0.25 pt) was equally effective whether applied as a foliar spray or through drip irrigation. Reduced-risk products azoxystrobin, mandipropamid and mefenoxam showed promise in greenhouse trials. Azoxystrobin prevented basil downy mildew (1 foliar spray, 4 oz), and calibrachoa death due to P. drechsleri applied alone (2 drenches, 0.9 oz) or in a tankmix (2 drenches, 0.5 oz) with another product. Mandipropamid prevented calibrachoa death due to P. drechsleri (2 drenches, 8 fl oz) and basil downy mildew (1 foliar spray, 4, 6, 12 fl oz). Mefenoxam 1 fl oz reduced osteospermum root rot (2 drenches), calibrachoa death due to P. drechsleri (2 drenches), basil downy mildew (1 foliar spray), and coleus downy mildew (1 drench). Volumetric spore samplers were placed at 8 Michigan sites in 2010. Oomycete (cucurbit downy mildew) sporangia were detected in the atmosphere at all sites via the spore samplers by 3-13 May. All sites except Allegan and Frankenmuth had daily sporangial counts <340. Numbers >1,000 were observed at Frankenmuth between 20 Jul and 12 Sep, and peaked at 220,893 on 1 Aug. Numbers >1,000 were observed at Allegan between 10 Aug and 10 Sep, and peaked at 39,915 on 15 Aug. Daily sporangia numbers and confirmation of downy mildew was continually uploaded to the For Growers page at Dr. Hausbeck's website.

    Topic 5: Natural ventilation design and control

    9. Improve control strategies as an alternative to existing vent control systems (AZ, NJ).

    10. Continue our efforts to use CFD techniques to evaluate greenhouse natural ventilation systems (AZ, NY, OH, IL).

    AZ continued working on developing 3D CFD models to analyze the effect of high pressure fogging on greenhouse climate uniformity. The study is directed towards analyzing the effects of nozzle placements (i.e. in vertical and horizontal in the greenhouse domain), nozzle placement angles for climate uniformity. AZ actively involved in organization of CFD sessions in GreenSys2011 and also activities of CFD working group under ISHS. AZ is also taking leading roles in the organization of the 1st Symposium on CFD Applications in Agriculture, which will be held as a concurrent symposium under the 2012 CIGR EuroAgEng conference in Valencia, Spain.

    11. Continue efforts to improve the efficiency and effectiveness of greenhouse fog cooling systems (AZ, IL, NJ, OH, NY).

    AZ developed and implemented a climate control strategy for a naturally ventilated greenhouse equipped with a variable high pressure fogging system. The strategy that was developed included variable rate of fog introduced into the greenhouse, a dynamic control of the air ventilation openings, and it considered the contribution of cooling and humidification from the crop by evapotranspiration. The fogging system was operated to keep a VPD set point and the vents were operated based on an enthalpy set point to achieve a desired greenhouse inside conditions (i.e air temperature and relative humidity) for crop production. The developed strategy maintained the VPD close to the selected set point for all the experimental periods evaluated. Both in simulations and experiments, the enthalpy set point was reached only when the outside air specific enthalpy was lower than the set point and when the fogging rates used were sufficient to humidify all the incoming air needed to reach the enthalpy set point. When both VPD and enthalpy set points were reached, the greenhouse air temperature remained around desired levels. Comparisons of the developed strategy in the study to another strategy based on VPD set point, fixed ventilation opening rates and using a fixed high pressure fogging rates showed that 30.3% and 23.27% higher water and energy savings were possible with the strategy developed. Variable fogging rates strategy maintained temperature (RMSEt=2.87 oC) and relative humidity (RMSERH=7.12%) closer to pre-established set points, compared to the constant fogging rates strategy (RMSEt=4.22 oC and RMSERH=20.07%, respectively).

    Other accomplishments not specifically related to the 2008-2013 NE 1035 Multistate Research Project objectives:

    A document titled Guidelines for Monitoring and Reporting Environmental Parameters for Experiments in Greenhouses is under development by the International Committee for Controlled Environment Guidelines, chaired by A.J. Both.

    One of the most difficult problems for those wishing to create and operate a successful CEA facility is to find head growers able to manage large hydroponic facilities. NY has received funding to initiate a Controlled Environment Agriculture (CEA) and Modified-Environment Agriculture (MEA) technology transfer center for New York State. A series of workshops has begun, ranging from overview presentations for the general public, to workshops focused on potential and current CEA and MEA owners and managers. Additionally, summer internships have been created to begin the process of training employees and managers of CEA facilities in colder climates, such as New York State.

    NY has worked with Cycloptics Technologies, LLC (http://cycloptics.com/), to install and test more efficient plant lighting luminaire designs. A walk-in plant growth chamber has been retrofitted with the new luminaires, which provide twice the PPF intensity compared to the T12 VHO fluorescent lighting originally installed. In addition to improved energy efficacy, light uniformity is improved, particularly near the chamber walls. Further luminaire designs have been completed for research greenhouses to light plants uniformly while preventing light spill-over into the aisles, and commercial greenhouses to provide lighting intensity uniformity and improved efficacy. As soon as available from the manufacturer, these luminaires will be installed and their performances monitored and quantified.

    NY: Silicon (Si) is not regarded as an essential plant nutrient, but has received increasing attention from the plant nutrition community due to enhanced response of plants in terms of salt and drought tolerance under conditions of adequate Si supply. Floriculture producers want to know if its economically beneficial to add Si. To this end, we have conducted experiments to determine which floriculture species accumulate Si and if there are benefits for abiotic stress tolerance. About half of the species that we have studied show enhanced salt tolerance with Si supplementation. Interestingly this does not seem to depend on the degree to which the species accumulates Si. Silicon also improved the post-harvest performance and drought tolerance of potted Poinsettia plants.

    NY: Greenhouse production uses intensive amounts of water and fertilizer. Conventional overhead watering allows excess water, fertilizers, and pesticides to leach to surface and ground waters. In closed irrigation systems, excess water is captured and reused. While these closed systems limit water pollution, most New York State greenhouse producers have not adopted these systems, in part, due to expensive costs of installation. In fall 2010 use of different rates of controlled release fertilizers (CRF) were compared to conventional liquid fertilizers (LF). Nutrient leaching and plant performance was measured. We found that CRF adoption at the label medium to high rate led to plant growth equal to conventional LF. CRFs applied at the medium to high rate led to a reduction in nitrogen and phosphorus runoff by five- to ten-fold compared with LF.

    OH: Activities continued at a high level in our Hydroponic Lettuce Research Laboratory during the year 2010. The purpose for research in the Hydroponic Lettuce Research Laboratory is to develop and demonstrate economically sustainable, year-round, high quality, hydroponic horticultural crop production systems that operate well in energy efficient greenhouses. The first experiment for the year was conducted for The Cleveland Foundation starting with germination of seeds January 22. The objectives were to compare two light emitting diode (LED) lighting systems to high pressure sodium (HPS) lighting during winter weather while growing three lettuce cultivars and one herb cultivar in a hydroponic growing system. Yield, product quality, and water and nutrient use efficiency for each combination of cultivar, lighting and nutrient solution temperature were to be measured. The mature plants were harvested February 19. A total of seventeen conclusions/key observations were included in the final report (April 30) to the Foundation. A proprietary agreement precludes the results from being published for two more years. Huntsman International, LLC funded an experiment (Summer 2010) where the objectives were (1) to evaluate the growth of two hydroponically grown lettuce cultivars while using four polyurethane formulations as growing cubes and compare results to lettuce grown using coconut core cubes in addition to rock wool cubes and (2) to measure the impact of three levels of nutrient solution flow rate (1, 2 and 3 Lpm) on fresh weight produced and crop quality. To make these objectives possible, Huntsman funded the purchase of 18 acrylic flow meters (0.4 to 4 Lpm). Based on main effects, the results showed two of the polyurethane cubes yielded the same as rock wool while yields for coconut core were significantly greater. The main effects of flow rate showed fresh weights of lettuce grown at 3 Lpm were over 24% greater than for flow rates of 1 or 2 Lpm. Red Bib out yielded Green Bib for all six types of cubes. After a tornado destroyed our lab and greenhouse on Sept 16, no additional experiments were run in 2010.

    PA: A growth chamber was equipped with state of the art LED lighting fixtures and instrumented to monitor energy consumption and chamber environmental conditions. The lighting fixtures used were Philips iW Reach Powercore Architectural Lighting. These fixtures were used because in preliminary research Horticultural LED lighting fixtures were found to have inadequate light output to match the output of standard fluorescent and incandescent lamps used in comparison chambers. Energy consumption by the LED equipped plant growth chamber for lighting was reduced by about 85% and overall electrical consumption by the chamber was reduced by 40% compared to the control chamber. Plant growth was not affected. The fixtures used were much higher cost (~$4,000 each) and light output than currently available horticultural lighting systems and while this project demonstrates the potential for LED lighting, current costs and low light output from horticultural fixtures continue to limit cost effectiveness for commercial greenhouse or growth chamber applications. The fixtures used in this study and electrical use monitoring equipment will be installed in a greenhouse and compared with horticultural HID lighting to measure energy savings and plant growth in a greenhouse.

    Impact Statements:
    1. NE: Biomass furnace tests showed significantly hotter firebox temperatures with blending of biofuels, suggesting potential exists to improve heat exchange performance by taking advantage of the hotter flame temperatures.
    2. A special benefit with the particular forced air, biomass heating system developed by NE was a reduced greenhouse air humidity, which reduced crop disease problems. The imulation of stomatal canopy resistance by NE can be used to estimate strawberry water use by using a single pot energy balance calculation (simulating canopy resistance control) in real-time.
    3. The LabVIEW ® adaptive energy model and monitoring system developed by NE can assist greenhouse growers by monitoring the system. Low-cost electronic and instrumentation technology is available and feasible for monitoring and controlling greenhouse environments. Greenhouse crop production may be monitored and tracked on the basis of energy use. Instrumentation, sensor, and crop problems are easily observed over the internet.
    4. The multistate project helped UNL researchers to secure funding for several other greenhouse research and development projects. A strong cooperative alliance has been created between Agronomy and Horticulture, Biological Systems Engineering, Food Science, and the School of Natural resources. A number of UCARE undergraduate research projects have been funded. http://www.unl.edu/ucare/
    5. MI found that fluopicolide is very effective against water molds in the greenhouse and field. Alternating fluopicolide with industry standards that are B2 carcinogens would halve the amount of these carcinogens and decrease hazards to the growers and environment without compromising control. Hazards would be further decreased by incorporating effective, reduced-risk products, azoxystrobin, mandipropamid, and/or mefenoxam, into the alternating program.
    6. NY has initiated a series of workshops and student internships to train potential employees, managers, and owners of Controlled Environment Agriculture facilities.
    7. NY has upgraded a plant growth chamber with innovative luminaires from Cycloptics Technologies, LLC. The luminaires provide twice the photosynthetic light at bench level, while drawing half the electricity, compared to T12 VHO fluorescent lamps originally installed in the chamber.
    8. NY has installed a field test (beta test) controller in a commercial greenhouse that implements the daily light integral control algorithm patented by Cornell. Control suitability will be monitored and quantified during the coming year.
    9. PA found that the use of LED lighting in a plant growth chamber reduced energy consumption for lighting by 85% and overall electrical consumption by 40%.
    10. NJ: Information and research activities related to energy use and consumption by commercial greenhouse operations has been distributed and shared through fact sheets, trade journal articles, growers presentations and publications in scientific journals. Growers who implemented conservation strategies have been able to realize energy savings between 5 and 30%.
    11. NY found that when controlled release fertilizers at a medium to high label rate were used as the sole fertilizer addition in fall Poinsettia production that plant growth was equal to or greater than conventional liquid fertilizers while nitrogen and phosphorus leaching were reduced by more than five-fold.
    12. NE project investigators have been contacted by or have met with five grower groups, all interested in starting commercial strawberry production, for either fresh use or for wine production (new idea). One hydroponic tomato grower plans to visit, as a second Quonset house on campus is being prepared and begins growing strawberries during Fall 2011.
    13. The simulation of stomatal canopy resistance by NE can be used to estimate strawberry water use by using a single pot energy balance calculation (simulating canopy resistance control) in real-time.
    Last Modified: 23-Sep-2011

    Date of Annual Report: 08/22/2012

    Report Information:
  • Annual Meeting Dates: 06/25/12 to 06/27/12
  • Period the Report Covers: 10/2011 to 09/2012

    • Participants:
    Brief Summary of Minutes of Annual Meeting:

    URL: Copy of minutes
    Accomplishments:
    NE 1035 Annual Meeting The University of Connecticut (Storrs, CT) Nathan Hale Inn and Conference Center 855 Bolton Road, Storrs, CT

    June 25-27, 2012 Multistate Research Project Station Accomplishments Report

    PROJECT NUMBER: NE-1035

    TITLE: Developing and Integrating Components for Commercial Greenhouse Production Systems

    PROJECT DURATION: October 1, 2008 to September 30, 2013

    REPORTING PERIOD: May 1, 2011 to June 25, 2012

    OBJECTIVES:

    Topic 1: Energy conservation and alternative energy sources

    1. Evaluate biomass derived fuels for greenhouse heating (NE, NJ, NY).

    NE Finished an analysis of blended biomass fuels for greenhouse heating as a journal article to be submitted to Engineering in Agriculture. Biomass furnace tests have shown significantly hotter firebox temperatures with blending of biofuels, suggesting potential exists to improve heat exchange performance by taking advantage of the hotter flame temperatures.

    2. Develop decision support systems for alternative fuel heating systems (NJ, NE, NY, PA, CT).

    Nothing to report

    Topic 2: Water and nutrient solution management

    3. Develop protocols for irrigation that maximize water use efficiency while maintaining crop growth and quality (CT, ME, NE, PA, NY, OH, AZ).

    NY has conducted further work on exogenous compounds to increase the salt tolerance of floriculture crops. With declining availability of freshwater for agriculture production, irrigation poor quality (saline) irrigation water may become increasingly necessary. A commercially available kelp extract (Stimplex) was found to improve the growth and flower number of some bedding plants in response to extreme salt stress. Kelp extract improved photosynthesis of salt-stressed plants. Silicon and Brassinosteroid (a naturally derived hormone-like material) both enhanced the growth of petunia plants exposed to salt stress and improved growth of un-stressed plants such that they were much bigger than control plants. Further research should be undertaken to see if Brassinosteroid applications can yield larger, higher quality plants under standard greenhouse conditions.

    OH designed and constructed an Argus Nutrient Delivery System was used to deliver water and nutrients to 344 trees during the 2011 summer growing season. The system was custom designed and constructed to accurately and precisely deliver nutrient solutions during short irrigation events (5 to 10 min) in small volumes (10 to 50 L) to container-grown plants typically required for treatments in research plots. This nutrient delivery system successfully controlled pH for all treatments to a specified set point of 6.0 (+/- 5%) using a dilute sulfuric acid solution.

    Two hundred Austrian pine (Pinus nigra) trees were maintained over winter in OH (after growing through the summer of 2010) and subjected to canker and insect induction summer 2011 before being harvested the last week of July. Five nutrient treatments were specified and delivered to the trees. This interdisciplinary OARDC Research Enhancement Competitive Grant project entitled, Testing the Systemic Induced Resistance Hypothesis: Implications for Plant Defense Theory was designed to test a new model that integrates the phenomenon of pathogen-induced systemic resistance with the growth /differentiation balance hypothesis in tripartite systems that include Austrian pine, the canker pathogen Diplodia pinea, and two pestiferous insects, the pine engraver and the European pine sawfly. The results are pending.

    NE used Capillary mats (CapMat", Phytotronics, Inc, Earth City, MO USA) to water and fertigate a winter strawberry cultivar production study in a Quonset greenhouse. Plants were grown in 2011-2012 on two separate 6 ft by 60 ft benches with improved CapMats. Six-inch pots were interfaced with the CapMat fabric, along with white top/black bottom polyethylene as a reflective mulch and vapor barrier. CapMats were wetted using twin wall tubing installed under the capillary fabric. A special jig device was used allow to cut holes in the plastice to allow individual pots access the mat. Individual flag pots of strawberries were monitored with capacitance moisture sensors (Decagon Devices, Inc. Pullman, WA), calibrated to the potting mix formula, and installed at three zone locations (north, middle, and south) over the sixty foot length of each bench. An automatic clock typically fertigated the CapMats on selected time event schedules. Daily watering event was adjusted according to crop and environmental conditions to minimize night time humidity levels and to reduce plant disease and pest pressure. An electronic meter was used to measure greenhouse water use during the growing period. The pots were adequately watered at the three zones (50-60% volumetric content). A water meter and n electronic gas meter were used to monitor water and natural gas use. Furnace and ventilation events controlled by a Groton II system (ACME Engineering and Manufacturing, inc., Muskogee, OK) were also monitored using electronic split core, current sensors and LabVIEW programming. The strawberry cultivar studies were conducted during 2010, 2011, and 2012, and will continue into 2013.

    Stomatal canopy resistance was again simulated, as a model and LabVIEW control variable for the strawberries grown in an East Campus Greenhouse and CapMat fertigation system. An adaptive, real-time dynamic energy model (VI) based on the First and Second Laws of Thermodynamics and psychrometrics accounted for canopy entropy production, net radiation, sensible and latent heat exchanges for the strawberries. Measured canopy TLeaf and air temperatures Tair, relative humidity žair, and radiation data were transmitted wirelessly from three bench zone locations to a host computer, using sensors and National Instruments LabVIEW® software. Stomatal resistance (rLeaf - s/m) was simulated as a LabVIEW Proportional Integral Differential (PID) controller (subVI) in order to balance net energy for the canopy. Latent results compared favorably from draw-down pot moisture contents, measured with the capacitance sensors.

    4. Develop irrigation protocols and filtration or sterilization methods for nutrient solution recirculation that minimize the effects of pathogens or toxic metabolites (CT, NY, OH).

    Topic 3: Sensors and control systems

    5. Improve volumetric water content sensor efficacy (ME, NY, OH).

    ME developed a propagation system that turns on fog based on measurements from capacitance sensors (EC-5; Decagon Devices). This system is being tested to determine if rooting quality and/or water use efficiency in propagation may be improved using sensors. A capacitance sensor automated irrigation system currently in use in ME was upgraded to utilize EC-TM sensors (Decagon Devices) which measure both volumetric water content and substrate temperature. It may be possible to more easily and precisely model plant water use with these new sensors.

    6. Improve sensor control of the greenhouse aerial environment (light, carbon dioxide, temperature, and moisture) (NJ, OH, NY, NE, AZ).

    Effort was devoted in OH to modeling cooling effects of shade curtains as a part of establishing a user friendly interface that will allow a decision support tool to be used for general greenhouse aerial environment control. The tool uses local weather climate, greenhouse structural design, desired temperature set points, and structure specific spectral characteristics for greenhouse temperature prediction.

    Topic 4: Environmental effects on plant composition

    7. Develop greenhouse design and management protocols to maintain high nutrition values of vegetable crops grown under various environments (AZ, CT, NJ).

    AZ continued a project to develop cultivation practices of hydroponic (soilless culture) for strawberry suitable for semi-arid greenhouses. In this project, we have analyzed total soluble solid concentration as well as titratable acidity as quality attributes of strawberry fruit. Data will be analyzed for understanding seasonal effect over the 6-month production (November to April).

    CT determined the nutritional value of locally-grown salad greens and compared these values to those of the same crops that were produced in distant regions and sold in supermarkets. Locally grown produce had higher concentrations of sucrose and starch, and lower concentrations of free amino acids than produce shipped from distant regions. Sugars were increased in summer in lettuce, and in winter in spinach. The local produce likely retained more of the sugars found in plants immediately after harvest. The high amino acids in non-local produce may be an early sign of tissue breakdown due to prolonged storage. However, we found no instances in which mineral- or organic acid composition differed between local compared to distance production. These concentrations were not affected by seasonal changes in environment. Most differences in composition could be attributed to production conditions and/or the size of the plants.

    Lettuce tissues can accumulate 4000 ppm nitrate on a fresh weight basis when grown under low light intensity in heated greenhouses. Timely removal of nitrate from the nutrient solution in hydroponics may lower tissue nitrate. Tissue nitrate changed more rapidly than total nitrogen, or growth responses. However, nitrate in petiole tissue changed more slowly than in leaf blade or roots, and larger plants have more biomass in petiole tissue. Thus, growth in N-depleted nutrient solution clears nitrate from lettuce more slowly for large compared to smaller lettuce plants. Several growers have started producing salad greens in greenhouses and high tunnels, and lettuce in hydroponics. The information developed by this project will help growers tailor the composition of leafy vegetables to avoid metabolites of concern, such as nitrate, and to optimize the concentration of beneficial nutrients.

    Integrated sunlight intensity has a profound effect on rate of growth, morphology, and composition of lettuce. Both fertilizer and temperature can be controlled for plants grown in hydroponics in greenhouses, allowing the effect of sunlight intensity to be determined in isolation from other factors. The relationship between daily integrated irradiance and tissue composition was examined in hydroponic lettuce (Lactuca sativa L. var Buttercrunch) grown at various times of year under natural sunlight in a greenhouse. Daily integrated irradiance varied from 5 to 24 Mj.m-2.day-1. Tissue composition was measured for plants that varied in size from 4 to 300 g fw/plant at high irradiance, and 2 to 180 g fw/plant at low irradiance. Irradiance was normalized per unit leaf area by dividing by LAI when LAI > 1. Whereas reduced nitrogen and potassium showed an increase with irradiance on a fresh weight basis, they showed a decreasing trend on a dry weight basis. Sugars, which increased rapidly with irradiance for small plants on a fresh weight basis, showed no trend for larger plants on a dry weight basis. Of all of the metabolites observed, nitrate and malate showed the greatest relative change with daily integrated irradiance, when expressed on either a fresh or dry weight basis. Nitrate decreased with irradiance, and the change was greater on a dry weight basis. Malate increased with irradiance, and the trend was greater on a fresh weight basis. Large plants had more nitrate and malate, and the contents were more sensitive to irradiance in large compared to small plants. The trends with plant size and irradiance for nitrate were equal and opposite those for malate. There appeared to be compensation between nitrate and malate within the plant. However, in other studies comparing nitrate-sufficient and nitrate-depleted plants, nitrate depletion lowered malate, and sugars were the metabolite that increased to compensate quantitatively for the depletion in tissue nitrate. The information developed in this project will help growers understand the variation in composition of leafy vegetables due to season, or sunlight intensity. This may be of value to promote the dietary benefit of these crops when grown at different times of year, or in different climates.

    In CT, an experiment designed to examine the effects of partial- and full-saturation sub-irrigation on Pansy with or without salinity in the source water was conducted. Previous studies in CT demonstrated that partial-saturation sub-irrigation reduced water usage, produced more compact plants and reduced the incidence and spread of water borne disease. These studies also demonstrated that containers under sub-irrigation accumulated high EC levels in the soil profile. While ground water in CT is relatively pure with very low alkalinity or salinity, alkalinity and salinity are of concern in many parts of the country. High alkalinity or salinity in source water may influence optimal water management strategies for greenhouse crops. The study was conducted to determine how elevated salinity in the source water would affect crop management with partial- and full-saturation. Plants under partial-saturation accumulated less leaf, stem and total dry mass than plants under full-saturation. In both partial- and full-saturation plants exposed to 0.5g/l NaCl (EC of 1.0 mmhos/cm in source water) accumulated greater leaf, stem and total dry mass than plants not exposed to sodium. Sodium concentrations leaf tissue for plants exposed to sodium was 689 mg/kg under full-saturation and 203 mg/kg under partial-irrigation. For plants not treated with sodium source water leaf tissue sodium concentrations were 64.5 mg/kg under full-saturation and 50.6 mg/kg under partial-saturation. Surprisingly, pansy appeared to benefit from sodium at EC 1 mmhos/cm and there was no interaction between irrigation regime (full- v. partial-saturation) and elevated EC source water. Experiments were initiated to characterize the effects of media composition on the dynamic uptake of water in sub-irrigation using tall and short containers. This study is in progress.

    8. Develop greenhouse design and management protocols to maximize production of beneficial compounds such as phytochemicals and biopharmaceuticals (NY, AZ, CT, MI, NJ).

    MI evaluated dosages and application intervals and methods of 33 active ingredients for water mold control in the greenhouse and field. Especially effective were a biopesticide (phosphorus acid salts), reduced risk products (mefenoxam, fenamidone, mandipropamid, azoxystrobin), new chemistries (flupicolide, ametoctradin/dimethomorph), B2 carcinogens (etridizole, chlorothalonil, mancozeb), and industry standards (dimethomorph, propamocarb). Alternating active ingredients is recommended for water mold control.

    AZ re-analyzed data obtained in 2005-2006 year-round production of tomato under varied EC to express total soluble solid concentration (TSS) and lycopene concentration in tomato fruit using linear models with selected environmental variables (efflux solution EC, daily light integral (DLI), air temperature, and daytime VPD). For both quality attributes, efflux solution EC was shown to have the highest influence, followed by DLI for TSS and temperature for lycopene.

    9. Improve control strategies as an alternative to existing vent control systems (AZ, NJ).

    Nothing to report

    10. Continue our efforts to use CFD techniques to evaluate greenhouse natural ventilation systems (AZ, NY, OH, IL).

    AZ developed and validated a 3D CFD model comparing the simulation results with experimental data. The overall model included a turbulence model, solar radiation model, crop evapotranspiration model (with a user defined function), and a discrete phase change model. Simulation study is ongoing with multiple scenarios created to analyze the effect of high pressure fogging system integrated within a naturally vented greenhouse on greenhouse climate uniformity. The study aims to evaluate the effects of nozzle placements, nozzle placement angles for climate uniformity, side/roof vent configurations. AZ actively involved in CFD session organization for GreenSys2011 conference in Greece. AZ takes leading roles in the organization of the 1st Symposium on CFD Applications in Agriculture being held under the 2012 CIGR EuroAgEng conference in Valencia, Spain on July 8-11, 2012.

    11. Continue efforts to improve the efficiency and effectiveness of greenhouse fog cooling systems (AZ, IL, NJ, OH, NY).

    AZ completed a three year BARD project on developing climate control strategies for a naturally ventilated greenhouse equipped with a variable high pressure fogging system.

    A new cooling control strategy, which considered the contribution of humidification and cooling from the crop, was evaluated first by computer simulations. The strategy controlled the amount of fog introduced into the greenhouse, as well as the percentage of vent openings to maintain desired values of greenhouse atmospheric vapor pressure deficit (VPD) and enthalpy, respectively, which would consequently affect air temperature. The performance was compared to constant fogging rate strategy, which was based on VPD. On average, the new strategy saved 36% water and consumed 30% less electric energy. Smaller air temperature and relative humidity fluctuations, and more consistent control, were achieved by varying the fog system operating pressure to provide a more optimum amount of fog for evaporative cooling. It was demonstrated by simulations that dynamically varying the fog rate and properly selecting the number of nozzles, savings of water and electric energy were increased, while still maintaining acceptable VPD and temperature. The developed strategy was implemented experimentally with a four-day experiment in the research greenhouse to maintained desired air temperature (24-25 oC) and humidity (<70% RH) (based on a VPD [1.0 kPa] and air specific enthalpy [56 kJ/kg] set points). The performance of the control strategy developed were satisfactory to maintain greenhouse indoor climate close to the set points with 1.1±0.4 kPa and 26±1.7 oC for inside air VPD and temperature, respectively (with relative humidity of 67±8 %). The implementation results demonstrated that the control strategy was capable of reducing the air VPD by an average of 4.2 kPa when the average outside air VPD was 5.4 kPa, air temperature by an average of 10.5 oC when the average outdoor air temperature was 37 oC, and the greenhouse relative humidity was increased about an average of 52% compared to outside during the four-day experiments on June 18, 19, 29, and July 3, 2011.

    OH found the efficiency of a commercial direct-fired heater can be improved by better management of air exchange in a greenhouse. Direct-fired heaters have been considered for greenhouse heating due to their high heating efficiency and generation of CO2. By discharging combustion products and byproducts into a greenhouse directly, some direct-fired heaters claim a combustion efficiency of 99.99% compared to 80-94% for indirect-fired heaters that discharge combustion exhaust outside of a greenhouse. While discharging the heat and CO2 into a greenhouse, water vapor produced is a combustion byproduct that also adds moisture load to a greenhouse environment. The goal of this research was to assess energy efficiency of a direct-fired heater and its impacts on greenhouse aerial environment attributes such as humidity, CO2, and ethylene. The results showed that the net heating efficiency of a direct-fired heater, including fuel consumption due to humidity management is 89 %. The direct-fired heater greenhouse has higher CO2 levels than indirect-fired heater while both types of heaters provided similar temperatures, relative humidity, and have no measureable level of ethylene. To improve the net heating efficiency of the direct-fired heater operation, more efficient air exchange management strategies are desirable for providing optimum amounts of outside air to meet the needs of combustion and dehumidification.

    Other accomplishments that do not necessarily relate to the 2008-2013 NE 1035 Multistate Research Project objectives:

    NY has investigated the use of vermicompost as the basis for organic transplant production. Following work from previous researchers we found that a potting mix with 10% vermicompost was suitable for optimal growth of crops such as basil and pepper which have lower fertility requirements. Heavier feeders such as tomato and lettuce required additional inputs of organic fertilizer beginning 3 weeks after transplanting to optimize plant size. We have worked with three commercial organic growers to address some of their concerns, such as developing recommendations for using organic approved acids (natural acetic and citric acids) to lower root-zone pH.

    AZ, The Lunar GreenhouseOutreach & Teaching Module (LGH-OTM) includes the Controlled Environment Agriculture Center, together with its partners Hungry Planets, Sadler Machine Company [Arizona], Aero-Sekur [Italy] and the Steckler and Space Grants programs of NASA, whose goal is to provide platforms presenting science, technology, education, food security and production, with educational demonstrations. The LGH-OTM, a portable version of the lab design LGH, will be exhibited around the US to demonstrate and provide outreach and training for audiences of all ages. The first display of the LGH-OTM at San Diego County Fair (SDCF), June 8, to July 5, 2012 entitled, "Out of this World," anticipates audiences of 1.5 million. Nearly 10,000 students in 400 lower, middle and high school classes are committed to attend the "Growing Out of this World food" exhibit area, where the LGH-OTM is spotlighted. The Lunar Greenhouse program is based on more than a decade of research at the UA-CEAC in collaboration with Sadler Machine Co, beginning with the South Pole Food Growth Chamber through Raytheon Polar Services Company and the National Science Foundation (NSF), and with continued sponsorship by NASA, NSF and various aerospace companies including Italy's Aero-Sekur and the Franco-Italian Thales Alenia Space.

    In OH, the Hydroponic Lettuce Research Laboratory was restored February 1, 2011 in a temporary greenhouse at a new location on the Ohio Agricultural Research and Development Center campus after a tornado destroyed the original laboratory and greenhouse September 16, 2010. The purpose for research in the Hydroponic Lettuce Research Laboratory is to develop and demonstrate economically sustainable, year-round, high quality, hydroponic horticultural crop production systems that operate well in energy efficient greenhouses. Three experiments designed to evaluate and optimize hydroponic lettuce growing processes in a greenhouse were conducted during the past twelve months (October 1, 2010 to September 30, 2011). The first experiment (February 6 to March 24, 2011) was conducted as a follow up experiment to one that was conducted Summer 2010. Five proprietary formulations of polyurethane cubes were compared to traditionally-used rock wood cubes while growing two cultivars (Green Bib Flandria RZ and Red Bib Skyphos RZ) at three growing solution flow rates (1 Lpm, 2 Lpm and 3 Lpm). The second experiment (March 19 to April 29, 2011) compared three lettuce cultivars (Butterhead Lettuce FIDEL, Multileaf Lettuce MULTY and Red Oak Leaf FERRARI) at three flow rates (1 Lpm, 2 Lmp and 3 Lpm) while evaluating molybdenum concentrations at three levels (0.02, 0.20, and 2.00 ppm). The third experiment (June 10 to July 22, 2011) was designed to evaluate the growth of the same three lettuce cultivars at the same three flow rates while comparing the effect of adding three levels of a proprietary biocatalyst (0, 50 and 100 ml) to the nutrient solutions. All treatments were evaluated based on average fresh weight produced per head and tip burn severity.

    Impact Statements:
    1. Biomass furnace tests have shown significantly hotter firebox temperatures with blending of biofuels, suggesting potential exists to improve heat exchange performance by taking advantage of the hotter flame temperatures.
    2. A Capillary Mat irrigation system system provides an effective and efficient water and fertilization system for potted plant crops. Three hundred plants used less than 60 gallons of water during an eight-month period. Strawberry water use can be estimated by using a single pot energy balance calculation (simulating canopy resistance control) in real-time.
    3. A commercially available kelp extract (Stimplex) was found to improve the growth and flower number of some bedding plants in response to extreme salt stress. Kelp extract improved photosynthesis of salt-stressed plants. Silicon and Brassinosteroid (a naturally derived hormone-like material) both enhanced the growth of petunia plants exposed to salt stress and improved growth of un-stressed plants such that they were much bigger than control plants.
    4. Cornell University has continued a series of workshops and student internships to train potential employees, managers, and owners of Controlled Environment Agriculture facilities. Three workshops have been presented to secondary school teachers, six to the general public, three for current greenhouse operators, and three for students. Two students completed internships in hydroponics during the summer of 2012.
    5. Cornell University has continued to field test (beta test) controller in a commercial greenhouse that implements the daily light integral control algorithm patented by Cornell. Control suitability will continue to be monitored and quantified during the coming year.
    6. The Cornell CEA website (www.cornellcea.com) has been significantly updated and continues to receive positive responses from users.
    7. A shade cloth model was developed as a decision support tool for the general greenhouse aerial environment. This tool uses local weather climate, greenhouse structural design, desired temperature set points, and structure specific spectral characteristics for greenhouse temperature prediction.
    8. A project to develop cultivation practices of hydroponic (soilless culture) for strawberry suitable for semi-arid greenhouses continued. In this project, we have analyzed total soluble solid concentration as well as titratable acidity as quality attributes of strawberry fruit. Data will be analyzed for understanding seasonal effect over the 6-month production (November to April).
    9. Production of salad greens in hydroponics in Connecticut has the potential to significantly increase the economic returns for Connecticut greenhouse operations if a greater content of nutrients can be used to promote the sale of locally grown food. However we found the method of production (field, greenhouse, or hydroponics), and size of the plants at harvest, were the dominant factors in determining tissue composition.
    10. Alternating or replacing B2 carcinogens with effective biopesticides, reduced risk products, or new chemistries would decrease the amount of carcinogens applied and lessen hazards to growers and environment without compromising control.
    11. It is possible to grow high quality Dianthus and Aquilegia with 15 L or less of water using water sensors. Water restriction effectively is an effective height control for Dianthus, Aquilegia, and Rosemary. To reduce growth, recommended volumetric water contents would be 25% (Aquilegia and Dianthus) or 30% (Rosemary). However, Rosemary should not be grown in extremely dry substrates (lower than 10% water contents) and should be irrigated consistently to avoid mortality.
    Last Modified: 05-Sep-2012
    Back to Top