Brief Summary of Minutes of Annual Meeting

Annual Meeting Rutgers, The State University of New Jersey New Brunswick, NJ 08901 June 3-4, 2004 Multistate Research Project Annual Station Accomplishments Report PROJECT NUMBER: NE-1017 TITLE: Developing and Integrating Components for Commercial Greenhouse Production Systems PROJECT DURATION: October 1, 2003 to September 30, 2008 REPORTING PERIOD: October 1, 2003 to June 1, 2004 REPORT DATE: June 1 2004 OBJECTIVES: Topic No. 1. Managing nutrients and water in greenhouses 1. Develop and evaluate methodologies (CT, NY, NE, OH, AZ, KY, NJ). Projects are underway at several locations that have potential to increase crop quality and yield, while optimizing nutrient and water use. These projects focus on innovative ways to sense and model the greenhouse environment and plant stress, and include: A study is quantifying the effects of environmental conditions and salinity on tomato plant growth status (AZ). Experimental data and modeling approaches are being taken to quantify stomatal resistance, transpiration rate and leaf temperature. The ability of reflectance sensors to detect plant response to electrical conductivity (EC) treatments is under evaluation. Researchers at OH are using load cells to measure and log changes in weight of potted plants every 10 min with controlled moisture tension in the potting medium. Evapotranspiration was measured and compared to potting medium moisture tension based on weight loss between irrigation events. NY researchers are evaluating and optimizing crop evapotranspiration in hydroponic production systems so that environmental control faults or problems can be detected. Lettuce crops are being grown with continuous and batch deep flow hydroponic systems, and evaporatranspiration is being modeled with the Penman-Monteith equation. The relationship between tip burn, which is a marginal necrosis of the rapidly expanding young leaves of lettuce caused by a localized Ca deficiency, root pressure, and vapor pressure deficit is being quantified. A modeling approach is also being used to investigate the relationship between nitrate and carbon as osmoticum for lettuce crops. 2. Evaluate the entire fertigation system (AZ, CT, NE, NH, NY, OH, PA). Optimum plant growth and health can be achieved by conserving water, nutrients and/or pesticides thus limiting runoff while avoiding plant stress due to deficient applications. Projects include: A quantitative model is being developed to simulate pH in container growing media (NH). As an outreach component to this project, a collaboration was initiated between NH and Massey University, New Zealand on interactive internet-based training tools including interactive case studies and technical information for horticulture. Analysis of irrigation water use efficiency in semiarid greenhouse, where water resources are scarce, is in progress by AZ in collaboration with Shingo Yokoi, Chiba University (Japan). A project with hydroponically-grown sweetpotato (Ipomoea batatas) by Japanese and AZ researchers monitored concentrations of critical individual chemical species over time in the hydroponic solution to provide for optimal nutrient management. A fertigation controller developed by OH (the OARDC Fertigator) delivered water and nutrients to nursery crops during the 2003 summer growing season. The decision of when to irrigate for the poplar trees was based on evapotranspiration during June, switched to tension-initiated irrigation events during July followed by scheduled events during August and September. Soil water sensors are also being evaluated. In PA, excessive salts were leached from Spent Mushroom Substrate (SMS) and the leachate was retained. It was concluded that SMS can be used as a component in the growing mix at a rate of either 25 or 50%. 1 part SMS leachate to 4 parts of water plus 50 ppm N from ammonium nitrate was as effective as a commercial fertilizer treatment. A study in NY compared three sterile, soil-less media (Agrifoam, Oasis, and Grodan) to determine which media characteristics favor seedling development and establishment, along with factors affecting pop-outs, a growth development in which the roots do not anchor into the media, causing the newly emerged seedlings roots to circle on the media surface. 3. Improve design of water and nutrient recirculation systems (NJ, NY, KY, OH, AZ, PA). An innovative improved version of the traditional fertilizer injection system has been designed and will be tested by AZ. Selected commercial organic fertilizers were used with limited success to grow bibb lettuce in a pond production system (KY). Water soluble materials derived from algae (Algamin and EcoNutrients) had little value as an organic fertilizer for lettuce in a tank hydroponic system. Water tests showed very low nutrient values in these fertilizer solutions. Dry weight of lettuce grown with a formulated organic fertilizer (Omega) was similar with Red Sails lettuce or significantly lower with Ostinata lettuce than lettuce grown in inorganic fertilizer. Work was completed to characterize evapotranspiration of nutrient film technique grown lettuce in a collaboration between KY and Brazilian colleagues. Evapotranspiration was found to be strongly influenced by light level and air VPD in naturally ventilated greenhouses with moderately warm to hot growing conditions. Continued efforts to develop a functional model of poinsettia root development and growth, as affected by the temperature in the root zone of the propagation media, were completed (KY). Root zone temperature optima for root initiation and root elongation stages for rooting in poinsettia cuttings was determined to be 28 and 26oC, respectively. Research by PA on green roofs shows promise to manage and treat stormwater, or irrigation runoff from greenhouses or nurseries and their support facilities. The Center for Green Roof Research at Penn State has six small (6x8) buildings, 3 with asphalt roofs and 3 with green roofs. Results from the fall of 2002 and summer of 2003 show that green roofs retained 20-100% of the runoff from storms measured during this period, and nearly 50% of the total summer rainfall in 2003. Runoff from green roofs contained significantly fewer nitrates, and air conditioning energy consumption was reduced. Topic No. 2. Managing the aerial environment for greenhouse plant production 1. Develop design and control recommendations for naturally ventilated greenhouses (OH, NE, NY, NJ). AZ researchers are collaborating with Japanese researchers to study interactions between environments inside and outside of the greenhouse, structure, and environmental control methods under semiarid climate. Tracer gas techniques were also used to develop empirical models of ventilation rates in a collaboration between AZ and Mexico. NY and OH researchers are collaborating in the use of Computational Fluid Dynamic (CFD) modeling to develop pressure coefficients as a function of wind speed and direction as input to a buoyancy model was defined. The buoyancy model will allow for quick analysis that can be used to set ventilation opening configurations. KY and NJ are researching climate control in high tunnel greenhouses. These low-tech greenhouses allow season extension and increased production compared with field production, without the energy use of heated greenhouses. 2. Enhance technology transfer and research in light integral control (CT, MI, NH, NY, AZ). NY and MI co-edited a book on greenhouse lighting Lighting Up Profits aimed at growers, industry, and university students. Chapters were serialized in an industry magazine, with 19 extension and research faculty from U.S., Canada, and The Netherlands (including NH, NJ, MI, and NY) contributing. Powerpoint slides and study questions were included as a training guide for growers and students, and were presented as a collaborative extension presentation (NH, NJ, MI) on greenhouse lighting at the OFA Short Course in 2004. The project will improve the energy-efficient use and profitability and reduce management risk of investment decisions in greenhouse lighting. Greenhouse plant production under the same daily light integral and temperature control protocol is more likely to be uniform, consistent, and of high quality. Researchers at NY developed a computer algorithm that considers a range of light and CO2 control combinations for the next decision period, estimates the ventilation rate expected, and finds the optimum (lowest cost) combination. The algorithm was tested by computer simulation (using hourly weather data for one year) and was predicted to save approximately one-half the lighting energy and nearly forty percent of the operating cost of supplementing the two resources, with no loss of plant production potential when lettuce is the crop of interest. Crop growth simulations models for hydroponic lettuce are also being improved and show promise for early fault detection in hydroponic production systems. Other research found that supplemental lighting did not appear to increase aphid populations in hydroponic lettuce. Topic No. 3. Integrating sustainable and economically profitable systems and processes for the greenhouse industry 1. Develop an economic analysis of the costs and benefits of supplemental lighting for seedling plugs, other greenhouse crop types, and photoperiodic lighting (AZ, CT, KY, MI, NE, NH, NY, NJ, OH). UNH initiated a collaboration with NY to develop educational programming and commercial data on greenhouse profitability. NJ developed a cost accounting program to help floricultural and nursery producers calculate crop production costs for their businesses. An internet version (http://aesop.rutgers.edu/~farmmgmt) is linked to the national risk management website. In addition, an Excel version allows producers to calculate costs for producing specialty cut flowers and greenhouse crops. A collaborative research project between NJ and NH provided and published data on growth and economics of plug production using supplemental lighting. KY researchers also evaluated production benefits of supplemental lighting for godetia cut flowers. 2. Improve the understanding of using shade to optimize production of high-quality greenhouse tomato for spring and early summer production (AZ, CT, KY, MI, NE, NH, NY, NJ, OH). A simple spreadsheet tool was developed by NJ allowing for the evaluation of single and multiple shade curtains on the light conditions in greenhouses. This tool can be used for locations where hourly weather data (wet and dry bulb temperature and horizontal radiation) and greenhouse characteristics are available for an entire reference year. CT found that shading a greenhouse increased the fraction of tomatoes that were marketable, and the marketable yield, in a comparison of greenhouse tomato yields across years, in some of which the greenhouses were shaded. In 2003, among other results, shade increased the fraction of marketable fruit from 54% under no shade to 63% under 50% shade, and in general fruit quality increased linearly with the degree of shade applied. 3. Quantitatively evaluate seasonal and annual water balances for greenhouses (AZ, CT, KY, MI, NE, NH, NY, NJ, OH). AZ is researching greenhouse water and energy-use efficiency, evaluating evaporative cooling methods in combination with both mechanical and natural ventilation systems. Two evaporative cooling methods will be studied; 1) pad and fan system and 2) high-pressure fog system. Water-use efficiency will be determined for both evaporative cooling systems, in combination with ventilation and shading, to compare the amount of water required to obtain the desired greenhouse conditions, while maintaining crop production and quality.