Brief Summary of Minutes of Annual Meeting

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 ?air, 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.