Progress 06/01/05 to 05/30/14
Outputs
Target Audience: The target audience includes students, scientists, extension personnel, and greenhouse and nursery growers. Students were reached by incorporating research results into undergraduate and graduate courses. Scientists and extension personnel were reached through scientific publications and preseantations at scientific meetings. Growers were reached through presentations at trade shows. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project has provided training opportunities for four graduate students, one post-doc, and one visting scientist in the past year. This has included student research, as well as particpation in scientific meetings. How have the results been disseminated to communities of interest? Results have been disseminated to growers through presentation at grower meetings in the US and Canada. Results have been disseminated to scientists and extension personnel through presentation at scientific meetings. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
This research aimed to develop proper guidelines for irrigating ornamental plants and to help develop the needed hardware and software tools (irrigation controllers and interface) to help growers implement these guidelines.. This objective was achieved in several steps: - Test and calibrate a variety of soil moisture sensors (i.e., ECH2O, theta, and heat dissipation probes) for use in soilless substrates - Quantify physiological and molecular responses of plants with different drought tolerance to changes in the substrate water content (plant water relations, photosynthetic rates, gene expression) - Collaborate on development and testing of an irrigation controller that can irrigate crops based on the soil moisture content of the substrate.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
van Iersel, M.W., M.R. Chappell, and J. Lea-Cox. 2013. Sensors for improved efficiency of irrigation in greenhouse and nursery production. HortTechnology 23:735-746.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Chappell, M., S.K. Dove, M.W. van Iersel, P.A. Thomas and J. Ruter. 2013. Implementation of wireless sensor networks for irrigation control in three container nurseries. HortTechnology 23:747-753.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Zhen, S., S.E. Burnett, M.E. Day, and M.W. van Iersel. 2014. Effects of substrate water content on morphology and physiology of rosemary, Canadian columbine, and cheddar pink. HortScience 49:486-492.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
OMeara, L., M.R. Chappell, and M.W. van Iersel. 2014. Water use of Hydrangea macrophylla and Gardenia jasminoides in response to a gradually drying substrate. HortScience 49:493-498.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Starry, O., J.D. Lea-Cox, J. Kim, and M.W. van Iersel. 2014. Photosynthesis and water use by two Sedum species in green roof substrate. Environmental and Experimental Botany 107:105-112.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Lea-Cox, J.D., W.L. Bauerle, M.W. van Iersel, G.F. Kantor, T.L. Bauerle, E. Lichtenberg, D.M. King, and L. Crawford. 2013. Advancing wireless sensor networks for irrigation management of ornamental crops: an overview. HortTechnology 23:717-724.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2014
Citation:
Ferrarezi, R.S., Marc W. van Iersel and R. Testezlaf. 2014 Subirrigation automated with capacitance sensors for production of salvia. Horticultura Brasileira
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Bayer, A., J. Ruter and M. van Iersel. 2013. Automated irrigation control for improved growth and quality of Gardenia jasminoides. Acta Horticulturae 1014:407-411 (Proceedings of the International Plant Propagators Society).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
van Iersel, M.W. and S.K. Dove. 2014. Temporal dynamics of oxygen concentrations in a peat-perlite substrate. Acta Horticulturae 1034:355-361.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Bayer, A. K. Whitaker, M. Chappell, J. Ruter, and M. van Iersel. 2014. Effect of irrigation duration and fertilizer rate on plant growth, substrate solution EC, and leaching volume. Acta Horticulturae 1034: 477-484.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Alem, P.O., P.A. Thomas, and M.W. van Iersel. 2014. Irrigation volume and fertilizer concentration effects on leaching and growth of petunia. Acta Horticulturae 1034:143-148.
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: The target audience includes students, scientists, extension personnel, and greenhouse and nursery growers. Students were reached by incorporating research results into undergraduate and graduate courses. Scientists and extension personnel were reached through scientific publications and preseantations at scientific meetings. Growers were reached through presentations at trade shows. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project currently provides training opportunities for four graduate students. This has included student research, as well as particpation in the 2013 meeting of the American Society for Horticultural Science. How have the results been disseminated to communities of interest? Results have been disseminated to growers through presentation at the 2013 OFA Shortcourse, North America's largest horticultural trade show. Results have been disseminated to scientists and extension personnel through presenation at the2013 meeting of the American Society for Horticultural Science. What do you plan to do during the next reporting period to accomplish the goals? Our efferts so far have focused on irrigation control. We hope to expand this work to include automation of fertilization as well. Findings will be disseminated through scientific and grower meetings, as well as journal articles.
Impacts
What was accomplished under these goals?
Irrigation and fertilization are tied together in the greenhouse and nursery industry. Excessive irrigation leaches fertilizer from the pots, thus necessitating additional fertilizer applications. This increases production costs for growers and can have a negative environmental impact. We have found that more efficient irrigation practices can reduce leaching of fertilizer. Using sensor-controlled irrigation to optimize irrigation, fertilizer applications can be reduced by 50%. This reduces production costs by approximately $2,000/acre/year and at the same time helps to protect surface and ground water form eutrophication. We have used a two prong approach to commercializing wireless sensor networks fro irrigation. Collaboration with Decagon Devices, a company with extensive expertise in sensors and sensor networks, will result in commercially available system in the summer of 2014. At the same time, we have developed low cost, sensor-based irrigation controllers that will allow small growers and homeowners to benefit from this technology at a greatly reduced price.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Bayer, A., I. Mahbub, M. Chappell, J. Ruter, and M.W. van Iersel. 2013. Water use and growth of Hibiscus acetosella Panama Red grown with a soil moisture sensor controlled irrigation system. HortScience 48:980-987.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
OMeara, L., M.W. van Iersel, and M.R. Chappell. 2013. Daily water use of Hydrangea macrophylla and Gardenia jasminoides as affected by growth stage and environmental conditions. HortScience 48:1040-1046.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2013
Citation:
van Iersel, M.W. and M. Chappell. Implementing sensor networks in nurseries. 2013. OFA Short Course, Columbus, OH.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2013
Citation:
van Iersel, M.W. 2013. Integrating soil moisture and other sensors for precision irrigation. OFA Short Course, Columbus, OH.
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2013
Citation:
Bayer, A., J. Ruter, and M. van Iersel. 2013. Irrigation volume and fertilizer rate influence growth and leaching fraction from container-grown Gardenia jasminoides. 2013 International Plant Propagators Society Southern Region of North America annual meeting, Athens, GA.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
van Iersel, M.W. 2013. Wireless sensor networks: Precision irrigation in greenhouses using soil moisture sensors. E-gro webinar
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2013
Citation:
Thomas, P.T., M. Chappell, J.M. Ruter, E. Lichtenberg, and M.W. van Iersel. 2013. Wireless sensor networks for automated irrigation control in container nurseries: implementation and economic impact. 2013 Annual Conference of the American Society for Horticultural Science, Palm Springs, CA.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Results from this project have been presented at a large number of scientific, professional, and grower meetings, including scientific meetings in the US and Brazil, grower meetings in Georgia, Tennessee, and Chile, and the Irrigation Show, the largest trade show in this area. The following presentations were made: van Iersel, M.W. 2012. Integrating soil moisture and other sensors for precision irrigation. 2012 Irrigation Show and Education Conference. Orlando, FL van Iersel, M.W. 2012. The plant propagation industry in the United States. International seminar on Propagation Technologies and Certification of Nursery Plants. Rancagua, Chile. van Iersel, M.W. 2012. Efficient water use during plant propagation. International seminar on Propagation Technologies and Certification of Nursery Plants. Rancagua, Chile. van Iersel, M.W. 2012. Automating irrigation: the evolution of an intelligent design. Department of Horticulture, University of Georgia. Athens, GA. van Iersel, M.W. 2012. Proposal Reviews: What Happens After Submission 2012 Annual Conference of the American Society for Horticultural Science, Miami, FL. van Iersel, M.W. 2012. Using dataloggers for measurement and control of environmental conditions. 2012 Annual Conference of the American Society for Horticultural Science. van Iersel, M.W. Wireless Sensor Networks for Monitoring and Controlling Irrigation in Greenhouses and Nurseries. X Congreso Latinoamericano y del Caribe de Ingenieria Agricola - CLIA e XLI Congresso Brasileiro de Engenharia Agricola - CONBEA Londrina - Parana, Brazil. van Iersel, M.W., L. OMeara, and M. Chappell. 2012. Environmental effects on water use of gardenia and hydrangea. 2012 Center for Applied Nursery Research Open House. Duluth, GA. van Iersel, M., M. Bayer, L. OMeara, A. Peter, P. Thomas, M. Chappell, J. Ruter and S. Wells. 2012. Wireless sensor networks for automated irrigation control in greenhouses and nurseries. 2012 Conference of the Southern region of the American Society for Horticultural Science. Birmingham, AL. PARTICIPANTS: Individuals working on the project include University of Georgia graduate students Alem Peter, Mandy Bayer, and Lucas OMeara. Collaborating faculty members include Matthew Chappell, John Ruter, Paul Thomas, and Sheryl Wells. Collaborating organizations include the following universities: University of Maryland, Carnegie Mellon University, Colorado State University, and Cornell University and the following companies: Decagon Devices, Antir Software, Evergreen Nurseries, and McCorkle Nurseries. A training opportunity was provided to the horticultural science community through a workshop on sensor technology at the American Society for Horticultural Science and to the irrigation community through a session organized at the 2012 Irrigation Meeting. TARGET AUDIENCES: The target audience for this project includes the horticultural science community, irrigation professionals, and the US greenhouse and nursery industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The US greenhouse and nursery industry supplies consumers with ornamental plants, vegetable seedlings, and fruit trees for use in gardens throughout North America. Irrigation in greenhouses and nurseries can be difficult to manage, because many of the plants are grown in fairly small pots that may need to be watered several times per day. And most greenhouse and nurseries grow a wide variety of crops; adjusting irrigation of all these crops based on the actual watering needs is too time-consuming for growers. To address this challenge, we have developed wireless sensor networks to help growers automate irrigation based on the actual water needs of their crops. The principle is simple: soil moisture sensors are inserted into the pots and they measure how much water is present. The sensors are connected to a node, which radios the data to a computer, where the data is presented in charts. Growers can see whether the various crops have adequate water. More importantly, they can use this computer to instruct each node when and for how long to turn on the irrigation. This way, plants get watered only when needed and only with the amount of water required. We are testing this system in a commercial nursery in Georgia. For the testing, we decided to pick gardenia Radicans, one of the most challenging crops produced by this nursery. Typically, this nursery loses about 20 - 30% of the plants during the production, and most of these losses are due to watering too much. Using the wireless sensor networks to automate the irrigation of this crop eliminated these losses. And just as importantly, we found that we could actually grow the crop much faster; the normal production cycle for these plants is 14 months, but with precision irrigation we were able to grow them in only eight months. The precision irrigation had various benefits to the nursery: since none of the plants died because of overwatering, the nursery could sell 2,000 more plants than they anticipated. And shortening the production cycle from 14 to 8 months reduced the production inputs (labor, fertilizer, pesticides). Combined, the extra plants that were sold and the reduced production costs resulted in an economic gain of $20,700 or approximately $1/sq. ft. The required hardware only costs about $6,000, so the return on investment was just a few months. This research not only benefited this nursery, but also society at large: by irrigation more precisely, the nursery withdraws les ground water, leaving more water for other uses. And after seeing the benefits of better irrigation practices, the nursery has adjusted their irrigation practices throughout the entire nursery. We conservatively estimate that this has reduced their water use by 100,000,000 gallons per year, enough water to supply about 800 households or about 2,000 people.
Publications
- Kim, J., A. Malladi, and M.W. van Iersel. 2012. Physiological and molecular responses to drought in Petunia: the importance of stress severity. Journal of Experimental Botany 63:6335-6345.
- Chappell, M. and M. van Iersel. 2012. Sensor network deployment and implementation in commercial nurseries and greenhouses. Proceedings of the 2012 Irrigation Show and Education Conference. 10 p.
- van Iersel, M.W. 2012. Integrating soil moisture and other sensors for precision irrigation. Proceedings of the 2012 Irrigation Show and Education Conference. 15 p.
- Ferrarezi, R. S., M.W. van Iersel, and R. Testezlaf. 2012. Fotossintese e crescimento de plantas de salvia cultivadas por subirrigacao em sistema semi-continuo para medicao de CO2. Proceedings of the X Congreso Latinoamericano y del Caribe de Ingenieria Agricola - CLIA e XLI Congresso Brasileiro de Engenharia Agricola - CONBEA Londrina - Parana, Brazil.
- Ferrarezi, R.S., M.W. van Iersel, and R. Testezlaf. 2012. Sensores capacitivos no monitoramento e controle da subirrigacao na producao de salvia. Proceedings of the X Congreso Latinoamericano y del Caribe de Ingenieria Agricola - CLIA e XLI Congresso Brasileiro de Engenharia Agricola - CONBEA Londrina - Parana, Brazil.
- van Iersel, M.W. , M.R. Chappell, P.A. Thomas, J.M. Ruter and S. Wells. 2012. Wireless sensor networks for monitoring and controlling irrigation in greenhouses and nurseries. Proceedings of the X Congreso Latinoamericano y del Caribe de Ingenieria Agricola - CLIA e XLI Congresso Brasileiro de Engenharia Agricola - CONBEA Londrina - Parana, Brazil.
- Chappell, M., M. van Iersel, E. Lichtenberg, J. Majsztrik, P. Thomas, J. Ruter, and S. Wells. 2012. Benefits of precision irrigation of Gardenia augusta Heaven Scent. Reducing shrinkage, shortening the cropping cycle, and economic impact. Proceedings of the SNA research conference 57:321-323.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Studies on the effect of substrate water content on the growth and physiology were conducted by graduate students. Data have been analyzed and summarized. Results have been presented at scientific meetings (annual meeting of the American Society for Horticultural Science, Southern Region ASHS, Center for Applied Nursery Research Open House, Sixth JKUAT scientific, technological and industrialization conference a tJomo Kenyatta University of Agriculture and Technology, Juja, Kenya, and the 2011 Irrigation Show) PARTICIPANTS: Tom Pratt, Notre Dame Stephanie Burnett, University of Maine Kate Garland, University of Maine Jongyun Kim, University of Georgia Mandy Bayer, University of Georgia Alem Peter, University of Georgia Lucas O'Meara, University of Georgia Sherryll Wells, University of Georgia Matthew Chappell, University of Georgia John Ruter, University of Georgia Paul Thomas, University of Georgia Kevin Whitaker, University of Georgia Kengelle Q Chukwurah, University of Georgia Sue Dove, University of Georgia TARGET AUDIENCES: The commercial greenhouse and nursery industry is our target audience. We are engaging this industry through on-farm trials of our new automated irrigation systems. This allows growers to gradually become familiar with this technique, and the collaborating growers will hopefully help us spread this technology throughout the industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We have shown that controlling substrate water with the use of soil moisture sensors allows growers to manipulate plant growth. Use of chemical growth regulators is the most common way for growers to slow down growth; altering irrigation can provide similar results, but at much lower costs. We have installed wireless sensor networks in commercial nurseries, allowing growers to monitor the water status of their crop and to make irrigation decisions accordingly. This has given growers better control over plant quality while preserving water.
Publications
- Garland, K.F., S.E. Burnett, M.E. Day, and M.W. van Iersel. 2012. Influence of substrate water content and daily light integral on photosynthesis, water use efficiency, and morphology of Heuchera americana. Journal of the American Society for Horticultural Science 137:57-62
- Mattson, N.S. and M.W. van Iersel. 2011. Application of the 4R nutrient stewardship concept to horticultural crops: Applying nutrients at the right time. HortTechnology 21:667-673
- van Iersel, M.W., S. Dove and S.E. Burnett. 2011. The use of soil moisture probes for improved uniformity and irrigation control in greenhouses. Acta Horticulturae 893:1049-1056
- Bayer, A., M. Chappell, J. Ruter, and M. van Iersel. 2011. Managing growth of Hibiscus acetosella by controlling substrate moisture with sensor controlled irrigation. Proceedings of the 2011 meeting of the IPPS Southern Region meeting. http://ipps-srna.org/pdf/2011Papers/21-Bayer-student.pdf
- Chappell, M., M. van Iersel, S. Dove, J. Ruter, P. Thomas, A. Bayer, L. O'Meara, P. Alem, R. Ferrarezi, J. Kim. 2011. Monitoring Environmental Conditions and Substrate Water Content to Increase Efficiency of Irrigation in Nurseries. 2011 Irrigation Association: Innovations in Irrigation Conference
- Wells. S., M. Chappell, J. Ruter, P. Thomas, and M. van Iersel. 2011. Monitoring substrate water content in nurseries: More efficient irrigation and reducing leaching and runoff. ASABE Paper No.: 1111254. ASABE, St. Joseph, MI, p. 183-190
- Pratt, T.G., M.W. van Iersel, M. Higginson, and Q. Xue. 2011. Remote sensing of soil moisture with RF polarimetry. ASABE Paper No. 1100017. St. Joseph, MI, p. 4948-4958
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Activities: studies were conducted to test for interaction between irrigation and fertilization in greenhouses. We developed a new approach to control irrigation in closed subirrigation systems in greenhouses. This approach provides growers with better control over plant quality. We also developed a system to continuously and precisely quantify CO2 exchange and water use of whole plants, a valuable tool for drought physiology research. We also studied the use of soil moisture sensors for irrigation control in nuresries. Products include new guidelines for irrigation and fertilization in greenhouses and nurseries. Dissemination: results from this project have been presented to the scientific community at the Southern Nursery Association research conference and the annual meeting of the American Society for Horticultural Science. PARTICIPANTS: Research is done in cooperation with Drs. Paul Thomas, John Ruter, Sheryl Wells, and Matthew Chappell at the University of Georgia, Dr. Stephanie Burnett at the University of Maine, Drs. John Lea-Cox and Andrew Ristvey at the University of Maryland, and Drs. George Kantor and David Kohanbash at Carnegie Mellon. Graduate students involved in this project include Jongyun Kim, Mandy Eads, Alem Peter, Manuel Astacio, and Lucas O'Meare, as well as a visiting PhD student from Brazil, Rhuanito Soranz Ferrarezi. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
We now have a much improved understanding of how daily water use of greenhouse and nursery crops is affected by plant size and environmental conditions. This information is used to provide quantitative irrigation guidelines to greenhosue and nursery growers. We also know how the growth of greenhouse crops is affected by different levels of water in the substrate, and how that depends on fertilizer rates.
Publications
- van Iersel, M.W., S. Dove, J.G. Kang, and S.E. Burnett. 2010. Growth and water use of petunia as affected by substrate water content and daily light integral. HortScience 45:277-282.
- Kim, J. and M.W. van Iersel. 2010. Photosynthesis and water use of vinca (Catharanthus roseus) during drought: the effect of different drying rates. Proceedings of the SNA research conference 55:114-120.
- Miralles Crespo, J., and M. van Iersel. 2010. Automated control of water content and electrical conductivity in soilless substrates: proof of concept. Proceedings of the SNA research conference 55:367-373.
- Astacio, M.G. and M.W. van Iersel. 2010. Determining the Effects of Exogenous Abscisic Acid on Evapotranspiration of Tomato (Solanum lycopersicon). Proceedings of the SNA research conference 55:264-271.
- van Iersel, M.W. and S.E. Burnett. 2010. Plant water use and drought stress physiology: Manipulating irrigation for efficient water use and high quality plants. Proceedings of the Taiwan - USA Symposium on Technology of Cultivation and Molecular Breeding for Ornamental Crops. T.-F. Hsieh, T.-E. Dai and L.-J. Wang (eds.) Special publication of TARI No. 145. p. 31-54.
- Miralles, J., M.W. van Iersel, and Banon, S. 2010. Development of irrigation and fertigation control using 5TE soil moisture, electrical conductivity and temperature sensors. The Third International Symposium on Soil Water Measurement Using Capacitance, Impedance and TDT (2010, Murcia, Spain), Applications, Paper 2.10, p. 1-9.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Activities: studies were conducted to test new sensors that can be used for irrigation and fertilization control in greenhouses. Subsequent experiments were conducted using these sensors to quantify plant water requirements and to determine optimal fertilizer levels in the substrate. Events related to this project include presentations at the University of Georgia Ornamentals Open House, a webinar presented on-line to a world-wide audience. Products include new guidelines for irrigation control in greenhouses and nurseries. Dissemination: results from this project have been presented to the scientific community at the Southern Nursery Association research conference and the annual meeting of the American Society for Horticultural Science. PARTICIPANTS: Research is doen in collaboration with Drs. John Ruter, Paul Thomas, and matthew Chappell at the University of Georgia, Dr. Stephanie Burnett at the University of maine, and Dr. John Lea-Cox at the University of Maryland. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
We now have a much improved understanding of how daily water use of greenhouse crops is affected by plant size and environmental conditions. We also know how the growth of greenhouse crops is affected by different levels of water in the substrate.
Publications
- Kang, J.-G. and M.W. van Iersel. 2009. Managing fertilization of bedding plants: a comparison of constant fertilizer concentrations versus constant leachate electrical conductivity. HortScience 44:151-156.
- Fernandez, R.T., J. Lea-Cox, G. Zinati, C. Hong, R. Cabrera, D. Merhaut, J. Albano, M. van Iersel, T. Yeager and D. Buhler. 2009. NCDC216: A New Multistate Group for Water Management and Quality for Ornamental Crop Production and Health. Proceedings of the SNA research conference 54:35-38.
- van Iersel, M., R.M. Seymour, M. Chappell, F. Watson, and S. Dove. 2009. Soil moisture sensor-based irrigation reduces water use and nutrient leaching in a commercial nursery. Proceedings of the SNA research conference 54:17-21.
- Kim, J. and M.W. van Iersel. 2009. Daily water use of abutilon and lantana at various substrate water contents. Proceedings of the SNA research conference 54:12-16.
- van Iersel, M. and M. Chappell. 2009. Using soil moisture sensors to control irrigation in a production setting. Georgia Green Industry Association Journal 20(4):23.
- Lea-Cox, J., T. Fernandez, G. Zinati, C. Hong, R. Cabrera,D. Merhaut , J. Albano, M. van Iersel, and D. Buhler. 2009. NCDC216: A new multistate group for water management and quality for ornamental crop production and health. 2009 CSREES National Water Conference; St. Louis, MO.
- van Iersel, M.W. 2009. Using soil moisture sensors for controlled drought stress experiments. HortScience 44:981. Fernandez, R.T., J. Lea-Cox, G. Zinati, C. Hong, R. Cabrera, D. Merhaut,
- J. Albano, M. van Iersel, T. Yeager and D. Buhler. 2009. NCDC216: A new multistate group for water management and quality for ornamental crop production and health. HortScience 44:1188-1189.
- Kim, J. and M.W. van Iersel. 2009. Modeling daily water use of abutilon and lantana based on environmental conditions. HortScience 44:1092-1093.
- Kim, J. and M.W. van Iersel. 2009. Daily water requirements of petunias as a function of plant age and environmental conditions. HortScience 44:1019.
- van Iersel, M.W. and S. Dove. 2009. Water content in soilless substrates: spatial and temporal dynamics. HortScience 44:1019-1020.
- van Iersel, M.W., S. Dove, and S.E. Burnett. 2009. The use of soil moisture sensors for improved uniformity and irrigation control in greenhouses. Scientific program, GreenSys 2009, p. 102.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Research projects in 2008 focused on using soil moisture sensors to control irrigation of greenhouse crops and determine daily water needs, develop models to describe the daily water needs of greenhouse crops based on plant age and environmental conditions, and conducting on-farm research to determine the practical impact of soil moisture sensor-controlled irrigation. Results have been disseminated through articles in scientific journals and trade magazines, as well as presentations at scientific meetings (2008 International Meeting on Controlled Environment Agriculture), trade shows (Southeastern Greenhouse Conference and Trade Show), and workshops (IV Annual Irrigation Scheduling Course, University of Lleida, Lleida, Spain). PARTICIPANTS: The research has been supervised by the PI on this project (Dr. Marc van Iersel), while several other faculty members from the University of Georgia participatred in the on-farm research (Rose Mary Seymour, Matthew Chappell, Adam Spiers) with assitance from the Pollution prevention Assistance Division of the Georgia Department of Natural Resources. On e graduate student (Jongyun Kim) has had the opportunity to participate in this research and will write a disseration on topics directly related to this project. TARGET AUDIENCES: The target audience consists of fellow scientists, growers, and students. The developed information has been extended to these audiences through presentation at various meetings and by integrating this new knowledge into my course material. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our research has shown that the daily water requirements of greenhoiuse crops are much lower than commonly believed and that greenhouse irrigation can be accurately controlled through the use of soil moisture sensors. Models have need developed to describe the daily water use of several greenhouse crops (abutilon, lantana, petunia) as function of plant age and environmental conditions. On-farm research has demonstrated to practical value of the use of soil moisture sensors for irrigation control. A large study with several thousand hydrangeas in a commercial greenhouse showed that soil moisture sensor-controlled irrigation resulted in water savings of 83% as compared to standard production practices. In addition, soil mositure sensor-controlled irrigation resulted in decreased leaching and runoff of fertilizer.
Publications
- van Iersel, M.W. 2008. Monitoring and controlling substrate water content in controlled environments. 2008 International meeting on controlled environment agriculture. Advances in research and design in CEA facilities, p. 46 (abstract).
- van Iersel, M. and Burnett, S. 2008. Greenhouse irrigation automation: How to apply water efficiently. Georgia Green Industry Association Journal 19(5):39-43.
- van Iersel, M. and Burnett, S. 2008. Irrigation automation: Current technology. Georgia Green Industry Association Journal 19(4):18-22.
- Burnett, S.E. and M.W. van Iersel. 2008. Morphology and irrigation efficiency of Gaura lindheimeri grown with capacitance-sensor controlled irrigation. HortScience 43:1555-1560.
- Nemali, K.S. and M.W. van Iersel. 2008. Physiological responses to different substrate water contents: screening for high water-use efficiency in bedding plants. Journal of the American Society for Horticultural Science 133:333-340.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Several experiments were conducted to determine the optimal irrigation strategy for bedding plant. Irrigation was controlled using soil moisture sensors, and water use of different crops was quantified. Physiological responses of plants to different irrigation treatments were studied as well. Findings were disseminated to growers though presentations to horticultural growers at the Georgia Green Industry Association Techshop in Atlanta, and the FarWest greenhouse and nursery trade show. TARGET AUDIENCES: The target audience are greenhouse and nursery growers throughout the US. Presentations aimed at growers were made at the Georgia Green Industry Techshop and the FarWEest trade show. In addition, several articles were published in trade magazine to provide growers with cutting edge information on irrigation management.
Impacts
The results from our studies showed that bedding plants can be grown without significant drought stress if the substrate water content is maintained at 30% or higher. Using soil moisture sensors for autmated control makes it easy to maintain such substrate water contents without any leaching of excess water or fertilizer. A new, simple approach to quantify drought stress was developed: measuring the area of individual leaves was shown to be at least as effective as much more complicated physiological measurements. The results from this research allow growers to achive large water savings while have less negative impact on the environment, since water use and runoff of nutrients can be reduced.
Publications
- Montesano, F., M. van Iersel, and P. Santamaria. 2007. Cosi si puo controllare la fertilizzazione in serra. (Translated title: This is how it is possible to control fertilization in greenhouses) Colture Protette. Orticoltura e floricoltura 36(2):21-30.
- Nemali, K., D. Radcliffe, and M. van Iersel. 2007. Plant available water and pore size distribution in soilless substrates. HortScience 42:1003 (abstract).
- Kang, J.G., M. van Iersel, and S. Burnett. 2007. Irrigation scheduling in greenhouses: Substrate water content effects on growth and physiology of vinca (Cataranthus roseus). HortScience 42:889 (abstract).
- van Iersel, M. 2007. La gestione della fertilizzazione nei sistemi con subirrigazione (Fertilizer management in subirrigation systems). In: P. Santamaria (ed.) I sistemi di allevamento in vaso can subirrigazione a ciclo chiuso. p. 53-65. Aracne editrice, Rome, Italy (ISBN 978-88-548-1190-4)
- Nemali, K.S., F. Montesano, S.K. Dove, M.W. van Iersel. 2007. Calibration and performance of moisture sensors in soilless substrates: ECH2O and Theta probes. Scientia Horticulturae 112:227-334.
- van Iersel, M. and S. Burnett. 2007. Using soil water sensors for efficient irrigation in greenhouses. Gauging the Green 1(1): 2, 3, 6.
- Burnett, S. and M. van Iersel. 2007. Better crops, less water. Irrigation automation can make a healthier plant using less water and with less leaching. Greenhouse Grower 25(8):66, 68, 70.
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Progress 01/01/06 to 12/31/06
Outputs
Water availabiltiy is an increasingly important issue for agriculture, incluyding the greenhouse industry. The objective of this project is to get a better understanding of how much water greenhouse crops require, and to develop more efficient irrigation systems. One of the pieces of lacking information is the required substrate water content (VWC) to maintain a high irrigation efficiency (IE) during production of bedding plants. Without this information, it will be difficult to optimize water-use in bedding plant production. In response, we have determined the substrate VWC that can maintain a high IE during production of bedding plants and identified bedding plant species with a high water use efficiency. We grew vinca, salvia, petunia, and impatiens at four constant levels of VWC (9, 15, 22, and 32%) and measured gas exchange and chlorophyll fluorescence parameters in plants. Regardless of species, rate of photosynthesis (A) was similar among the θ levels of
15, 22, and 32% but stomatal conductance to H2O (g) was lower at 15 and 22% compared to that of 32%. Because of higher water loss and little gain in A at 32% compared to 15 and 22%, irrigation efficiency in all four species is higher in the substrate VWC range of 15 to 22% than at 32%. Mesophyll conductance [gm, a measure of photosynthetic capacity] was higher in petunia than salvia but gas phase conductance to CO2 (gCO2, an estimate of water loss from leaves) was not different between the two species, which resulted in a higher WUE in petunia than salvia at a CO2 concentration of 400 ppm. This indicates that high photosynthetic capacity was responsible for higher WUE in petunia.
Impacts
We have determined to optimal amount of water that should be present in a substrate and have developed an irrigation controller that can maintain this water content in the substrate. We expect that growers will soon be ably to apply this technology in their greenhouses, which could lead to water savings of 50% or more.
Publications
- Nemali, K.S. and M.W. van Iersel. 2006. An automated system for controlling drought stress and irrigation in potted plants. Scientia Horticulturae 110:292-297.
- van Iersel, M.W. 2006. Respiratory Q10 of marigold (Tagetes patula L.) in response to long-term temperature differences and its relation to growth and maintenance respiration. Physiologia Plantarum 128:289-301.
- Scoggins, H.L. and M.W. van Iersel. 2006. In situ probes for measurement of EC of soilless substrates: effects of temperature and substrate moisture content. HortScience 41:210-214.
- Burnett, S.E., M.W. van Iersel, and P.A. Thomas. 2006. Medium-incorporated PEG-8000 affects elongation, growth, and whole-canopy carbon dioxide exchange of Tagetes patula. HortScience 41:124-130.
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Progress 01/01/05 to 12/31/05
Outputs
Reliable and affordable moisture sensors for measuring the water content in soilless substrates are limited. In this study, we examined the efficacy of two moisture sensors (ECH2O−10 and Theta probe ML2X) for measuring water content in soilless substrates. We developed calibration equations and analyzed the effect of increasing electrical conductivity (EC) and substrate temperature on the voltage output of probes. We found that a single equation (one for each probe) could be used to adequately measure water content in different custom-made substrates maintained at low EC and a substrate temperature of 23 C. The calibration equation developed for the Theta probe from substrates maintained at low EC could also be used in two commercial substrates with high EC (2.0 to 5.0 dS/m). Further measurements in substrates maintained at different water contents and EC levels indicated that the output of the ECH2O probe, but not the Theta probe, was significantly affected by
substrate EC. Increasing the temperature of the substrate from 10 to 40 C increased the voltage output of ECH2O probes by 1.88 mV per C, or on average 0.0022 m3/m3 water content per C. There was no effect of increasing substrate temperature on the Theta probe. It was concluded that ECH2O probes can be used in greenhouse operations requiring less measurement precision (like irrigation), however for accurate measurements of water content, the Theta probe is preferred.
Impacts
To make irrigation in greenhouses more efficient, we need to be able to accurately measure how much water is actually present in the substrate in which plants are grown. By testing a variety of sensors under a wide range of conditions, we have found sensors that can accurately measure how much water is present in pots. These sensors have great potential for use in automated irrigation systems. They can be interfaced with greenhouse controllers to automatically irrigate when the amount of water that is available to plants drops below a grower-determined set point. We expect that this will make irrigation in greenhouse much more efficient, and that 20-50% of water can be saved.
Publications
- Pennisi, S.V., M.W. van Iersel, S.E. Burnett. 2005. Photosynthetic irradiance and nutrition effects on growth of English ivy (Hedera helix L.) in subirrigation systems. HortScience 40:1740-1745.
- Burnett, S.E., M.W. van Iersel, and P.A. Thomas. 2005. PEG-8000 alters morphology and nutrient concentration of hydroponic impatiens. HortScience 40:1768-1772.
- Burnett, S.E., S.V. Pennisi, P.A. Thomas, and M.W. van Iersel. 2005. Controlled drought affects morphology and anatomy of Salvia splendens. Journal of the American Society for Horticultural Science 130:775-781.
- Burnett, S., P. Thomas, and M.W. van Iersel. 2005. Post-germination drenches with PEG-8000 reduce growth of salvia and marigolds. HortScience 40:675-679.
- Klingeman, W.E., M.W. van Iersel, J.G. Kang, R.M. Auge, J.L. Moore and P.C. Flanagan. 2005. Whole-plant gas exchange measurements of mycorrhizal 'Iceberg' roses exposed to cyclic drought. Crop Protection 24:309-317.
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