Brief Summary of Minutes of Annual Meeting

Topic 1: Water and Nutrient Management 1. Develop and test irrigation and fertilization practices to improve water and fertilizer use efficiency in greenhouse production A. Conduct research to further refine irrigation/fertilization systems Our research in 2015 looked at a variety of irrigation and fertilization systems including ebb-and-flow irrigation and sensor-automated irrigation. One benefit of our group is that we have diverse facilities. Collaboration allows us to provide recommendations to growers on a variety of efficient irrigation and fertilization systems that would not be in place at a single university due to cost and space limitations. One goal for the next few years is to survey water use and irrigation practices at greenhouses and nurseries. There is currently little information on the use of water in greenhouses and nurseries and irrigation practices. To address this, a graduate student from Virginia Tech is in the process of conducting a water use and irrigation practices survey of greenhouse and nursery operations. This will help inform future research for our group and others. One new, efficient irrigation system that we tested in 2015 automates delivery of water and fertilizer simultaneously in greenhouses through drip irrigation using sensors (GS3, Decagon Devices). This novel system was tested on Hellebore. We applied fertilizer at a range of electrical conductivities (0.25-2.0 dS?m-1) and water at two water contents (0.4 or 0.5 L?L-1). Control of both water and fertilizer was effective. However, plants fertilized at the lowest three electrical conductivity thresholds (0.25-0.75 dS?m-1) were never fertilized; fertility from starter fertilizer was sufficient to maintain those substrate electrical conductivity levels. Symptoms of crown rot, which our grower collaborator identified as a significant problem, did not appear on any plants. We also conducted research on partial or full saturation ebb and flow irrigation systems. The goal of this project was to determine the whether ebb and flow watering alleviate the effects of salinity stress on Poinsettia. Two cultivars of Poinsettia were grown under partial or full saturation irrigation using a standard fertilizer solution, with or without the addition of sodium. The volumetric water content averaged 0.25 and 0.33 L.L-1 prior to irrigation, and 0.5 and 0.67 L.L-1 following irrigation, for partial or full saturation regimes, respectively. At crop maturity, the electrical conductivity of the potting medium averaged 7.7 and 4.2 S.m-1 for plants exposed to salinity or not, respectively. Plants had lower dry weight with partial than full saturation. ‘Peterstar Red’ had greater dry mass and larger total laminar area than ‘Prestige Red’. Sodium concentrations in bract, leaf and stem tissue were highest (P<0.05) in plants exposed to salinity and these plants accumulated less K in stems and less P and Fe in bracts. Plants had less dry weight with added salinity than without, regardless of irrigation regime. In a second study with poinsettia, eight cultivars, including the two mentioned above, were grown with or without salinity from 1.2 g.L-1 NaCl and drip or ebb and flow watering. Cultivar and watering had effects on plant fresh weight, but salinity did not. ‘Peterstar Red’ had greater height and width than ‘Prestige Red’ and all other cultivars except ‘Snow Cap’, and more fresh weight that all except ‘Maren’ and ‘Snow Cap’. ‘Maren’ and ‘Peterstar Red’ had greater weight with salinity than with no salt under drip irrigation. ‘Snow Cap’ was the only cultivar that was heavier with no salt than with salinity under both drip and ebb and flow. Only ‘DaVinci’ had greater height under no salt compared to salinity under ebb and flow irrigation. ‘DaVinci’ ‘Premium Piccassa’ and ‘Prestige Red’ had the highest sodium in bracts under salinity with drip irrigation, while ‘Snow Cap’ had the least. ‘Ruby Frost’ had the most sodium in stems while ‘Snow Cap’ had the least. ‘Marble Star’, ‘Maren’, and ‘Peterstar Red’ had more sodium in stems under salinity with ebb and flow compared to drip irrigation. For all cultivars, added salinity resulted in lower K in leaves and stem. ‘Snow Cap’ was the cultivar with the least sodium in stems and in bracts under salinity, with either drip or ebb and flow irrigation. This cultivar also had the greatest plant height and fresh weight, under drip irrigation. The lack of sodium in all parts of ‘Snow Cap’, and low sodium in bracts and leaves of ‘Ruby Frost’, should be studied to find other cultivars that would thrive under conditions of poor water quality. Partial saturation watering can be used as an effective water management option when control of plant height and overall crop growth are desirable, and it limits the accumulation of sodium when raw water contains elevated salinity. We also explored filters for use in a variety of efficient irrigation systems. Laboratory column experiments were conducted to identify promising filter media that could be used in greenhouse filtration tests. Sand media containing nano-sized iron oxide particles embedded on the media surface, which carry positive charge at acidic or neutral pH, were packed into plastic columns. As plant pathogens are usually negatively charged, the hypothesis was that the positively-charged sites should attract pathogen spores and remove them from the water. The preliminary laboratory column studies used Phytophthora capsici zoospores suspended in solutions of 0.4 mM NaHCO3 + 9.6 mM NaCl or 0.4 mM NaHCO3 + 3.2 mM CaCl2. Results showed that the zoospores were readily attached to synthesized nano-sized iron oxide surface coating of filter sand (0.5–0.8 mm). The removal of motile zoospores was significantly less than that of the encysted zoospores, and the presence of NaCl or CaCl2 in water had no effect for the encysted (non-motile) zoospores. In general, nano-sized iron oxide coating enhanced the zoospore removal. The results suggest that through controlling parameters of zoospores (e.g., encystment), solution chemistry (e.g., ion type), or filter media type, zoospore removal can be optimized. B. Test irrigation systems in parallel utilizing the same set of greenhouse crops and cultural conditions to develop metrics for their use Six self-contained irrigation units were constructed. Each irrigation unit consisted of an ebb and flow benchtop connected to a filtration unit via two hydraulic pumps and two 130-liter holding reservoirs. This enabled water to be pumped through the filters, into the post-filter holding reservoir, onto the benchtop, and back into the pre-filter holding reservoirs automatically at a predetermined irrigation schedule via timers. Water levels in the holding reservoirs and water pressure in the filter unit were monitored at real time, along with the water and air temperature, and relative humidity. The filtration system consisted of capped 6-inch PVC columns filled with either (a) sand or (b) a novel iron oxide coated porous media. The design replicated, at research scale, a method of filtration that could be instituted in commercial greenhouses. For the preliminary trial, a known crop/pathogen system which would guarantee results was tested: squash/Phytophthora capsici. Twelve-day-old acorn squash (Cucurbita pepo) seedlings grown in 5-inch greenhouse pots in peat potting mix were placed onto the benchtop. Five hundred ml of zoospore suspension (4x105, P. capsici isolate SP98) was added to the pre-filter holding reservoir, resulting in a concentration of 5x103. The squash plants were irrigated twice daily for 10 minutes to prevent oversaturation of the growing media. Water samples were taken every 4 days from the holding tank, plated onto selective media, and enumerated after 2 days. The two-week trial was concluded upon 100% plant death in the inoculated control bench in the absence of a filtration unit. Fresh and dry weights were recorded. The iron oxide medium performed significantly better (P < 0.01) than the sand column and positive control according to data that were recorded as plant fresh weight (the fresh weight of the control plants was 72% less than the plants grown using the iron oxide media). The concentration of zoospores in both the iron oxide and sand media holding tanks were reduced after the initial filtration to < 90% of the control and remained low for the duration of the experiment compared to the inoculated control. At the final zoospore measurement, the sand media contained 83% fewer zoospores than the control, while the iron oxide media contained no zoospores in solution. Pythium was also tested in the filtration system using ‘Prestige Red’ poinsettia as the host-plant. In this trial, 15 poinsettia plants in 6-in pots were placed onto each of 6 benches. A sand filter and an activated carbon filter were tested using the same filtration design as outlined above. Additional treatments included Terrazole WP added to the water tank at the labeled rate, and a ‘diseased plant’ treatment that had 3 infected plants placed onto the bench to observe an alternate mode of pathogen spread. Pythium aphanidermatum zoospores were added to the holding tanks and were passed through the filters and irrigated onto the ebb and flow bench tops to initiate the experiment. Plants were irrigated 2x daily for 15 min to increase disease pressure. The trial was concluded after two months. The inoculated control displayed severe root rot and stunting. The sand filter, Terrazole treatment, carbon filter, and ‘diseased plant’ treatment, all had significantly higher (P < 0.05) foliar fresh weight and plant height than the inoculated control treatment. These results suggest that filtration may be useful in a greenhouse setting. The second run of the Poinsettia-Pythium experiment are currently in progress. After the completion of the experiment, the next trial will be initiated using a novel copper coated filter media and Pythium. Previous studies have shown copper to be effective at reducing zoospore mobility and attachment to roots. A copper filter media not only filters out zoospores but also inhibits growth of the fungus ? C. Develop outreach materials for commercial greenhouse operations for effectively implementing these systems to save water and fertilizer resources We have developed a variety of regional and national outreach materials to assist growers in reducing water and fertilizer usage in greenhouses. Two trade journal articles were published on the efficient use of water and fertilizer. One provided water and fertilizer recommendations for Hellebore that will help reduce resource use while minimizing disease problems. The second trade article discussed the use of sensors to save water in commercial greenhouse operations. New York has developed an outreach website on substrates and fertilizers for organic vegetable transplant production, available at: http://www.greenhouse.cornell.edu/crops/organic.html The website contains several trade journal articles, extension bulletins and videos. Results and grower recommendations from plant pathology work will be presented at extension meetings, such as the Michigan Greenhouse Growers Expo, a regional meeting held annually in conjunction with the Great Lakes Expo every December in Grand Rapids, MI. This meeting was attended by over 4,200 people from 42 states and 8 Canadian provinces in 2014. Proceedings from these meetings are published online (http://glexpo.com/education-program/session-summaries), and results and grower recommendations will also be published in extension newsletters such at the Michigan State University Extension News for Agriculture ? Floriculture (http://msue.anr.msu.edu/topic/info/floriculture). Topic 2: Alternative Energy Sources and Energy Conservation 2. Develop guidelines and approaches to improve greenhouse heating system efficiency Several regional and state wide projects are under-way to improve greenhouse heating system efficiency. In New Jersey, through various presentations, the operation and efficiency of various greenhouse heating systems has been discussed. These presentations were often accompanied by handout materials that provide additional information on heating systems, their proper operation and strategies for maximum conversion efficiencies. In New York, two software engineering projects (funded by the New York State Energy and Research Development Authority) are underway to develop tools used to determine energy use in Controlled Environment Agriculture operations. The first tool is, Greenhouse Energy Management (GEM), is a computerized tool to optimize electrical and thermal energy use in greenhouses. The tool allows highly selectable user settings for the greenhouse environment (heating, lighting, and carbon dioxide parameters) and estimates electrical and heating costs for locations across the U.S. using typical meteorological year data. The second project is developing an energy model for vertical farms in a warehouse environment including lighting, cooling, heating, and fan costs. The project is still in preliminary stages, early results have indicated that the energy costs of plant lighting are substantially higher than supplemental lighting in a greenhouse environment. Cooling and fan costs are also significant. Cooling costs can be reduced by enabling increased ventilation with outside air during months of the year when outside air is cooler than indoors. However, this options reduces the ability to use carbon dioxide enrichment. Funding was secured to develop a software tool that will compare the energy use and greenhouse gas emissions of producing vegetables in a greenhouse versus a warehouse environment, the results will be used to inform business and policy decision making. In Virginia, in continuing our greenhouse energy efficiency project funded by the Tobacco Commission, we conducted a November 2014 workshop for producers on greenhouse energy efficiency principles and what to look for onsite. A licensed auditor conducted a tour of a recently audited greenhouse. In January 2015, we conducted an in-service training for VCE agents and energy auditor professionals with detailed presentations by Dr. A.J. Both on heating and ventilation systems as well as by Dr. Jennifer Boldt and Adam Hall on the USDA Virtual Grower software. The speakers also led a greenhouse energy efficiency tour of ACF Greenhouses, one of the greenhouse operations participating in the grant program. Energy efficiency improvements at ACF will be estimated using the Virtual Grower software and then evaluated over the next season for actual energy savings attributed to the upgrades. In Virginia, a session on ‘Greenhouse Energy Conservation Practices and Opportunities’ was presented at the 2014 ‘Getting Started in the Greenhouse Business School’ in Blackstone, VA (Nov. 11-12, 2014) to the greenhouse industry and Extension agents. In Maine, a sustainable year-round agriculture group is studying solar panels, LEDs, and other energy saving technologies used in greenhouses. There are five demonstration greenhouses being built throughout Maine with various levels of energy saving technology (most include semi-transparent solar panels). Data will be collected on energy savings from solar panels and other technologies, which will be presented to the industry, Extension, and agriculture and horticulture students. This effort to increase year-round agriculture in Maine will take place over several years. The University of Maine horticulture program is collaborating with the Climate Change Institute to study energy savings at a new building under construction on campus. 1. Develop guidelines and approaches for the use of alternative energy sources An ongoing collaboration with colleagues in Japan has resulted in a publication on using heat pump systems for greenhouse cooling. Funding was secured to set up a demonstration wood biomass furnace in a greenhouse to reduce fossil fuel use and produce agricultural charcoal (biochar). The furnace, from ClearStak LLC, has been installed in a commercial greenhouse operation. During winter 2014-2015 wood biomass from municipal wood chips and willow chips from a willow biomass project have been secured. The furnace has significantly reduced operational reliance on fossil fuels. The project has reinforced that woodchip quality is important for the auto feed delivery system and efforts are now underway to perfect the grinding, screening, and drying process of the woodchips. In addition, experiments using the biochar projects as a soil or potting mix amendment have been initiated. Topic 3: Sensors and Control Strategies 2. Evaluate and develop novel sensors and environmental control strategies As part of the USDA SCRI LED project, an integrating sphere was used to evaluate the total light output and electric energy consumption of a variety of light sources. We also tested and evaluated instrumentation for electrical monitoring in greenhouses (USDA/NRCS project). 3. Outreach activities (presentation, publications, demonstrations) to stakeholders In New Jersey, a presentation was delivered on greenhouse environment control during the Greenhouse Production Short Course, NJ EcoComplex. Columbus, NJ. March 2-3, 2015. In 2014 seventeen New York State and four national presentations were made reaching more than 1,000 commercial greenhouse, high tunnel, and vegetable growers. Six trade journal articles reaching a national commercial greenhouse audience were published. A greenhouse open house on campus and a summer floriculture field day were held reaching more than 125 participants. Other accomplishments that do not necessarily relate to the NE-1335 Multistate Research Project objectives: None