Source: UNIVERSITY OF ARKANSAS submitted to
RESOURCE OPTIMIZATION IN CONTROLLED ENVIRONMENT AGRICULTURE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
Reporting Frequency
Annual
Accession No.
1019001
Grant No.
(N/A)
Project No.
ARK02639
Proposal No.
(N/A)
Multistate No.
NE-1835
Program Code
(N/A)
Project Start Date
Mar 19, 2019
Project End Date
Sep 30, 2023
Grant Year
(N/A)
Project Director
Dickson, RY.
Recipient Organization
UNIVERSITY OF ARKANSAS
(N/A)
FAYETTEVILLE,AR 72703
Performing Department
Horticulture
Non Technical Summary
The greenhouse and vertical farming industries are rapidly changing agricultural sectors in Arkansas. The introduction of new technologies, changes in production systems, new crops, and shifts in consumer markets continues to raise new questions for research. Problems associated with fertilizer nutrient, pH, and irrigation management are still major causes of poor plant quality and crop losses during production. Many greenhouse operations in Arkansas collaborate with the Arkansas Agricultural Experiment Station and Cooperative Extension on applied research and outreach related to improvement of production efficiencies, adoption of sustainable practices, and maintenance of a profitable business.The greenhouse industry in Arkansas and nation-wide is rapidly adopting the use of "soilless" (meaning lack of mineral field soil) growing substrates formulated with new wood fiber materials. This is primarily because wood fiber offers growers cost-savings, and is considered more sustainable compared to traditional substrate materials such as sphagnum peat moss and perlite. However, wood materials differ considerably in their physical and chemical characteristics, and recent research has shown that these materials affect nutrient and water use efficiency, plant quality and growth. Growers have reported a need to update fertilizer and irrigation strategies with wood fiber substrates, and the University of Arkansas is one of several main research groups working in this area.Plant species interact with the applied fertilizer and nutrient solution, which affects root zone pH and nutrient uptake. Therefore, greenhouse growers must match the applied fertilizer/nutrient solution with the plant species grown for optimal performance. However, much of this research has focused on plants during vegetative growth (Dickson et al., 2016; Marschner, 2013; Haynes, 1990), and species likely change their nutrient uptake patterns and effect on pH during other developmental such as fruiting and flowering (Sonneveld and Voogt, 2009). In addition, current hydroponic nutrient management strategies are often inefficient, wasteful, costly, and have negative environmental consequences (pollution, nutrient runoff). We aim to address these issues to help develop more efficient nutrient management strategies for growers.Quality of greenhouse-grown edible and food crops is often greatest at the end of production, and declines rapidly during post-production (shipping, retail, or consumer environment). Previous research has shown fertilizer strategies that build residual nutrients (particularly calcium, silicon, magnesium, and iron) in the root zone and plant tissues significantly enhance shelf-life quality and longevity. Use of certain agrichemicals, such as wetting surfactants, as well as other environmental and cultural factors (light, temperature, harvesting time) also influence post-production quality. Regional growers are interested in the development and potential to implement new strategies to enhance plant quality during post-production and for their customers.
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1021430101050%
2051430101050%
Goals / Objectives
Objective 2. To reduce fresh water use and evaluate alternative fertilizers and growing substrates for the production of greenhouse crops. Objective 3. To train growers and students to utilize emerging controlled environment agriculture technologies.
Project Methods
Objective 2: To reduce fresh water use and evaluate alternative fertilizers and growing substrates for the production of greenhouse crops.Objective 2, sub-objective 1a: Evaluate the effects of wood fiber on substrate physical properties and ability to retain fertilizer nutrients against leaching.We will use laboratory techniques to evaluate the effects of incorporating wood fiber into peat-based substrates on the overall substrate physical properties. Substrate blends will consist of varying proportions of Canadian sphagnum peat moss and wood fiber to mimic substrate blends used in commercial greenhouse production. Wood fiber will be manufactured from southern loblolly pine (Pinus taeda L.) or similar tree species. Peat moss and wood fiber raw materials will be adjusted to standard moisture contents and bulk densities prior to mixing. We will incorporate dolomitic limestone to adjust initial substrate-pH to approximately 6.0. We will formulate substrates just before use and store substrates in a closed environment until needed.Objective 2, sub-objective 1b: Wood fiber effects on nutrient managementGreenhouse experiments will evaluate the effects of wood fiber substrate and applied fertilizer nitrogen form and concentration on substrate pH, nutrient level, nutrient uptake efficiency, and plant quality of container-grown basil. Wood fiber substrates will vary in proportion of Canadian sphagnum peat moss and wood fiber material, simulating substrate blends used in commercial greenhouse production and mentioned in Objective 1a. Fertilizer nutrient solutions will be applied to plants at each irrigation, and will differ in concentration of ammonium (NH4-N), nitrate (NO3-N), and total nitrogen. Experiments will use a randomized complete block design with substrate blend and fertilizer nitrogen concentration as factors. Experiments will take place at the University of Arkansas Agricultural Experiment Station, where controlled-environment conditions will be maintained according to guidelines from Nelson (2005) and Erwin et al. (2018), with an average daily temperature of approximately 70°F and a minimum daily light integral (DLI) of 8 mol·m-2·d-1 of photosynthetically active radiation (PAR). Photoperiod extension will be provided using night interruption lighting and extra photosynthethic light will be supplied using high-intensity discharge lamps.Objective 2, sub-objective 1c: Wood fiber effects on irrigation managementWe will evaluate the effects of wood fiber substrate and irrigation practices on container water-holding capacity, evapotranspiration (plant water loss), and irrigation frequency. Since irrigation practices can influence substrate fertility, we will also evaluate effects on substrate-pH and EC, nutrient uptake and plant quality. Substrates will consist of varying proportions of new wood fiber material and Canadian sphagnum peat moss. Experiments will use a randomized complete block design with substrate type and irrigation as factors. Experiments will take place at the University of Arkansas Agricultural Experiment Station, where controlled-environment conditions described previously in Sub-objective 1b.Objective 2, sub-objective 1d: Wood fiber effects on nutrient and irrigation interactionsIn a greenhouse experiment, we will evaluate the interactive effects of wood fiber substrate, fertilizer nitrogen concentration, and irrigation practices on substrate-pH and EC, plant growth and quality, nutrient and water uptake efficiency. Nitrogen concentrations in the applied fertilizer solution and irrigation practices will be similar to those described in Sub-objectives 1b and 1c, respectively. Similarly, wood fiber substrates and data collection will be the same as described in Sub-objectives 1b and 1c.Objective 2, sub-objective 1e: Evaluate effects of applied fertilizer nitrogen and plant developmental stage on nutrient uptake and root zone pH for geranium and cucumber.Greenhouse experiments will evaluate the effects of plant species, applied fertilizer nitrogen, and plant developmental stage on individual cation-anion nutrient uptake and root zone acidity-basicity for cucumber (Cucumis sativus). Experiments will evaluate plant species, applied fertilizer nitrogen, and developmental stage as factors using a randomized complete block design. Experiments will take place at the University of Arkansas Agricultural Experiment Station and, with controlled-environment conditions measured as described previously in Sub-objective 1b.Objective 2, sub-objective 2: Develop fertilizer and agrichemical strategies to improve the performance and quality of container crops during post-productionGreenhouse experiments will evaluate the effects of applying a substrate surfactant in combination with fertilizer nutrients at the end of a greenhouse production phase on the post-production quality and shelf-life of container-grown basil. Experiments will evaluate use of a substrate surfactant, application method, and fertilizer regime as factors using a randomized complete block design. Experiments will consist of both a production and post-production phase. During the production phase, basil will be grown according to standard commercial greenhouse practices modified from Hamrick (2003). We will apply surfactant and fertilizer treatments at the end of the production phase when plants are of marketable quality, and evaluate during a production phase simulating a retail scenario in which plants only receive clear (no fertilizer) irrigation. Experiments will take place at the University of Arkansas Agricultural Experiment Station, where controlled-environment conditions described previously in Sub-objective 1b.Objective 2, sub-objective 3: Evaluate advanced nutrient management practices and harvesting practices in hydroponicsHydroponic experiments with leafy greens and vegetable food crops will be conducted at the University of Arkansas Agricultural Experiment Station. One focus will be on evaluating the effects of harvest time during the day, photoperiod, daily light integral, and temperature on shelf-life duration and quality of leafy greens. Major commercial leafy greens plant species and cultivars will be evaluated, with emphasis on both green and red leaf cultivars. A second focus will be on evaluating the effects of varying day/night soluble salt levels and nutrient formulations on leaf guttation, tip-burn, plant water use, and growth for hydroponically-grown leafy greens and herbs. A third focus will evaluate the effects of calcium and silicon foliar sprays during production for effects on chilling and physical (mechanical) damage during simulated shipping and post-production conditions using basil as a model crop. A fourth focus will be on modelling nutrient supply and crop demand effects in recirculating hydroponic systems.Objective 3. Train growers and students to utilize new environment technologiesProject results will be used to provide stakeholders updated fertilizer and watering guidelines and management strategies for growers through several educational channels. These channels include workshops such as the Horticulture Industry Show and the Arkansas Green Industry Conference. Results will also be presented to national stakeholder audiences in the form of research updates and webinars through e-GRO (electronic grower resources online), a national online greenhouse extension platform, as well as grower articles for popular trade magazines such as GrowerTalks and Greenhouse Product News. Project results will be included in a manuscript for publication in a peer-reviewed scientific journal for applied horticulture such as HortTechnology or HortScience.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The target audiences reached by efforts during this reporting period include but the following. Commercial producers of ornamental and edible food crops in hydroponic and soilless substrate culture systems. Production can be in greenhouses, high tunnels, indoor vertical farms, and other types of protected and controlled-environment agriculture. Members of the scientific community conducting applied research for protected and controlled-environment agriculture. Members may include researchers, professors, technical staff, post-docs, graduate and undergraduate students, and other members of universities and/or research institutes. Allied horticulture companies associated with crop production in protected and controlled environments. These include manufacturers and suppliers of electric lighting technologies, soilless substrates, fertilizers, agrichemicals, various plastic products, greenhouses, high tunnels, vertical farming units, and plant breeders. University students enrolled in coursework related to horticulture and crop production in protected and controlled environments. Courses include Greenhouse Management and Operation as well as Introduction to Hydroponic and Soilless Food Crop Production. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Results from this project have been published in HortTechnology, a peer-reviewed journal within the American Society for Horticultural Sciences. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting cycle, we plan to publish the remaining data sets on evaluating wood fiber as a soilless substrate component, which were collected during previous years. We plan to start projects on quantifying nutrient and water uptake for hydroponic leafy greens, and also on optimizing small fruit production in soilless substrates, focusing on evaluating long-cane techniques for blackberry and raspberry.

Impacts
What was accomplished under these goals? A new shallow aggregate ebb-and-flood (SAEF) culture system was evaluated with lettuce and basil and shown to be comparable to standard hydroponic systems such as nutrient film technique (NFT) and deep water culture (DWC). Nutrient and water supply in the SAEF system can be easier to manage compared to NFT and DWC hydroponic systems, therefore reducing the complexity and cost of fertilizer management during production. The SAEF system is particularly practical for ornamental container crop producers using ebb-and-flood irrigation, where ebb-and-flood irrigation systems can easily be modified to SAEF systems for the transition to food crop production. Several greenhouse growers in the United States and in the Caribbean islands have adopted the SAEF system as a means to transition into growing hydroponic leafy greens and herbs.

Publications

  • Type: Book Chapters Status: Awaiting Publication Year Published: 2021 Citation: Dickson, R.W., and B.E. Jackson. Growing Substrates. Ball Redbook. Meister Publishing.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Doty, S., R.W. Dickson, and M.R. Evans. 2020. Effects of culture system and transplant practices on soilless basil production. HortTechnology. DOI: 10.21273/HORTTECH04635-20
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Xiong, H., A. Shi, and R.W. Dickson. 2020. Effects of low temperature and low light on the physiology of tomato seedlings. American Journal of Plant Sciences. DOI: 10.4236/ajps.2020.112013
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Dickson, Ryan W., J.B. Ebba, P.R. Fisher, and C.N. Harris. In press. Fertilizer and Plant Growth Regulator Strategies for Improving Consumer Performance of Container-grown Petunia. HortTechnology.
  • Type: Theses/Dissertations Status: Published Year Published: 2020 Citation: Doty, S., R.W. Dickson, and M.R. Evans. Culture system and transplant practices influence basil production. Master's Thesis. University of Arkansas


Progress 03/19/19 to 09/30/19

Outputs
Target Audience:Target audiences for 2019 included the following: Growers, staff, and business owners working at commercial greenhouses and controlled-environment horticultural operations, particularly bedding plants and edible food crop operations. Technical service specialists, sales representatives, and customer support staff working for allied horticulture industries, including companies manufacturing and selling soilless substrates, fertilizers, plastic trays and pots, greenhouse and related construction services, and plant genetics. Students enrolled in ACCEPtS courses and at the University of Arkansas, Louisiana State University, Mississippi State University, Oklahoma State University. (ACCEPtS = the Alliance for Cooperative Course Exchange in Plant Sciences) Research, teaching, and extension faculty at land-grant universities collaborating on research and teaching activities in areas of horticulture and controlled-environment agriculture. Efforts of this project during 2019 included the following: Published research-based information on managing plant nutrition and soilless substrates in national trade magazines and through online extension services, with outreach targeted towards industry and academic audiences. Published research results in scientific peer-reviewed American Society for Horticultural Science journals targeted towards academic audiences. Instructed an online Greenhouse Management course and laboratory for students enrolled in ACCEPtS courses, targeting students at the University of Arkansas, Louisiana State Univeristy, Mississippi State University, and Oklahoma State University. Presented on hydroponic nutrient management, results on soilless substrate nutrient/pH research, and water quality research at national professional society meetings (American Society for Horticulltural Science and National Floriculture Forum) and international grower adn academic audiences (Canadian Greenhouse Conference). Currently writing book chapter on soilless substrates for the Ball Redbook with Dr. Brian Jackson at North Carolina State University. The Ball Redbook has been the premier commercial grower crop production publication for over 100 years. Collaborating with faculty and administration at the University of Arkansas on construction of a new greenhouse range. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Project results were used to provide stakeholders updated fertilizer and watering guidelines and management strategies for growers through several educational channels. Results were presented to national stakeholder audiences in the form of research updates and webinars through e-GRO (electronic grower resources online), a national online greenhouse extension platform, as well as grower articles for popular trade magazines such as GrowerTalks and Greenhouse Product News. Project results were also included in manuscripts being prepared for publication in a peer-reviewed scientific journal for applied horticulture such as HortTechnology or HortScience. Future channels will include workshops such as the Horticulture Industry Show and the Arkansas Green Industry Conference. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue working with wood products in soilless substrates, but also move more into strategies to improve water and nutrient management in closed hydroponic systems. Projects in this area will focus on designing hydroponic nutrient refill solutions, evaluating the potential to manage nutrient solution levels by electrical conductivity versus nitrogen concentration, and predicting optimal periods to replenish the hydroponic nutrient solution with a fresh nutrient supply.

Impacts
What was accomplished under these goals? The greenhouse and nursery industry is a large and rapidly changing sector of agriculture in Arkansas. The introduction of new wood fiber growing media and the demand requires growers to adjust their fertilizer and irrigation strategies. In addition, there is ever increasing need to reduce fresh water use as well as capture and reuse irrigation water used in agriculture to decrease economic and environmental costs. This project proposes to investigate fertilizer, irrigation, and growing media factors that influence plant nutrient uptake and water use efficiency in greenhouse and controlled-environment production. Anticipated impacts and outcomes include updated fertilizer and irrigation best management practices, guidelines for producing crops in new wood fiber growing media, and decreased nutrient and water runoff to the environment. Objective 2. To reduce fresh water use and evaluate alternative fertilizers and growing substrates for the production of greenhouse crops. Greenhouse and laboratory experiments were conducted to evaluate peat substrate amended with three types of pine wood fiber at 0%, 15%, 30%, 45%, and 60% (by volume) for effects on substrate physical properties, nitrogen immobilization potential, and plant growth and performance with container-grown petunia. Pine wood fiber was sourced from North American sourthern loblolly pine, Scots pine, and European white pine species. For comparison, additional treatments consisted of common substrate amendments including perlite, vermiculite, coconut coir, hammer-milled pine wood chips, pine bark, and rice hulls. Measured physical properties included dry bulk density, air and water porosity, and particle size distribution using techniques standardized at North Carollina State University substrates laboratory, lead by Dr. Brian Jackson. Nitrogen immobilization was measured using a standardized VDLUFA method from the German Association of Agricultural Sciences. Results indicated that substrate amendment type and percent amendment interacted in effect on all physical properties. Overall, increasing the proportion of wood fiber in the substrate had less than a 10% effect on bulk density and porosity, with no effects on nitrogen immobilization. In the greenhouse study, and with the exception of petunia grown in 60% rice hulls, all plants had the same growth rates, flower number per plant, and chlorophyll concentration in leaves. Rice hulls at 60% held very little water, and therefore chronic drought stress influenced performance. We concluded that amending wood fiber into peat substrates had little impact on plant performance as well as fertilization and irrigation practices. We recommend to growers incorporating wood fiber at between 20% and 40% of the total substrate volume, however, our data suggest that 60% may also be acceptable under certain cultural conditions. Objective 3. To train growers and students to utilize emerging controlled environment agriculture technologies. Our team met with two commerical greenhouse operations in Van Buren, AR, to conduct training on including wood fiber and managing wood products into their growing substrates. Both growers have invested significantly in use of wood products in substrates, and training included strategies to manage irrigation and fertilizer nutrients and minimize potential for nitrogen immobilization.

Publications

  • Type: Theses/Dissertations Status: Published Year Published: 2019 Citation: Ebba, J. Evaluating residual fertilizer strategies and plant growth regulators for potential to improve post-production performance of container crops. Master's Thesis. University of New Hampshire.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: G�mez, Celina, Christopher J. Currey, Ryan W. Dickson, Hye-Ji Kim, Ricardo Hern�ndez, Nadia C. Sabeh, Rosa E. Raudales et al. "Controlled Environment Food Production for Urban Agriculture." HortScience 54, no. 9 (2019): 1448-1458.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Dickson, R. W., & Fisher, P. R. (2019). Quantifying the Acidic and Basic Effects of Vegetable and Herb Species in Peat-based Substrate and Hydroponics. HortScience, 54(6), 1093-1100.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Harris, C.W., Dickson, R.W., Fisher, P.R., Jackson, B.E., Poleatewich, A.N. Evaluating peat substrate amended with wood fiber for effects on nitrogen immobilization and plant growth with container grown petunia. HortTechnology. In press.
  • Type: Other Status: Published Year Published: 2019 Citation: Dickson, R. Avoid tip burn in hydroponic lettuce. e-GRO Edible Alert. March 2019.
  • Type: Other Status: Published Year Published: 2019 Citation: Dickson, R. Overview of pH and electrical conductivity meters. GrowerTalks. January 2019.
  • Type: Other Status: Published Year Published: 2019 Citation: Dickson, R. Magnesium or micronutrient deficiency in basil? Dont be fooled. e-GRO Edible Alert. May 2019.
  • Type: Other Status: Published Year Published: 2019 Citation: Dickson, R. and R. Raudales. Avoiding ammonium toxicity. GrowerTalks. January 2019.
  • Type: Other Status: Published Year Published: 2019 Citation: Dickson, R. and R. Raudales. Trays too dry? GrowerTalks. January 2019.
  • Type: Theses/Dissertations Status: Published Year Published: 2019 Citation: Harris, C. Evaluating wood fiber substrates for effects on nitrogen immobilization, pH, and root zone nutrient concentrations in container-grown petunia. Master's Thesis. University of New Hampshire.