Progress 07/01/07 to 06/30/08
Outputs
OUTPUTS: In September of 2007, 12 wireless nodes from Carnegie Mellon University Robotics Institute were deployed at the Wye Research and Education Center's Experimental Nursery in Queenstown Maryland. The nodes were, coupled with Decagon Devices (Pullman, WA) EcH2O capacitance probes. The objective was to monitor potting substrate moisture content in nursery containers and control irrigation based on the needs of the plants in those containers. The wireless node monitoring/control system was challenged with a prescribed best management practice (BMP) known as cyclic irrigation, were plants are irrigated frequently throughout the day with short duration irrigation events scheduled by an irrigation controller with a timer. The experiment design included 24 experimental units, each a 1.3 m2 platform holding 25-7 liter containers with plants. Half of the platforms were randomly chosen to be irrigated with the wireless node system and the other half irrigated with the timer. The platforms and plants were irrigated with a high output microirrigation system. On each platform was a flow meter to measure applied irrigation volumes and a collection system for leachate including a flow meter to measure runoff. The EcH2O capacitance probes can detect moisture content and based on calibration data for the potting substrate, "set points" can be derived for turning an irrigation system on or off, depending on the level of available moisture for the plant in the container. Along with this research, a further $70K in grants ($24K HRI - Deployment of Wireless Sensor Networks for Real-Time Water and Nutrient Management, $46K Chesapeake Bay Trust - Irrigation Sensor Technology to Reduce Nutrient Runoff from Intensive Agricultural Operations) has enabled the continuation and expansion of this research project. Node systems have been deployed in two commercial operations in Maryland. Both systems are presently being used for moisture monitoring. The first is installed at Raemelton Farm near Adamstown Maryland, at an in-ground tree nursery where we have deployed a Decagon Devices sensor network to monitor soil moisture and other environmental variables, to better understand "orchard-type" systems. We have also deployed a sensor network at a cut-flower hydroponic greenhouse operation in Jarrettsville, MD, where we are monitoring moisture and electrical conductivity levels in perlite, a horticultural substrate made from heat-expanded hydrated obsidian (perlite). PARTICIPANTS: Andrew G. Ristvey (PI, University of Maryland, Wye REC) John D. Lea-Cox (co-PI, University of Maryland, College Park) David S. Ross (co-PI, University of Maryland, College Park) Felix R. Arguedas (Graduate Research Assistant, University of Maryland, College Park) George Kantor (Co-PI, sensor network development, Carnegie Mellon University Robotics Institute) TARGET AUDIENCES: Targeted stakeholders include all consumers of water resources including but not limited to the ornamental nursery, greenhouse and landscape industry along with irrigation managers; consultants and other professionals in the nursery and greenhouse industry and public agencies, including federal, state and local, that regulate water resources. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
During the 4 weeks of operation from late September into October, 2007 the Wye research wireless sensor network performed well, irrigating when the "on" set-point was reached and turning off irrigation before containers were up to water holding capacity. Cyclically timed irrigation was set for three times a day, delivering an average of 1 liter of water per plant per day for an average of about 30 liters per plant during the month with about 15% leaching from the pots. By comparison the wireless network controlled irrigation averaged less than one liter per plant throughout the month without leaching. These preliminary results suggest that this wireless sensor system can precisely control irrigation, and minimize leaching better than the recommended BMP. During the following growing season (spring, summer and fall of 2008), the timed controlled irrigation treatments were decreased, making the irrigation volume applied by timer very conservative. However, communication with the wireless node system was dependent upon reliable wireless transmission, which was intermittent throughout the summer of 2008, due to interference of water vapor from an intervening corn crop. Irrigation set-points for the sensor network system could not be adjusted on a regular basis, and the growth of plants under sensor control was reduced. The overall results showed that the wireless control system could slightly improve the efficiency of irrigation applications, based on plant use, compared to a very conservative cyclic irrigation management program. Occasionally a node or sensor would malfunction and the system would over irrigation, inflating the leachate volumes. At this time the data and sensor node output has not been analyzed to determine when that occurred. Once the wireless connectivity issue is corrected, the sensor nodes will function more efficiently. Presently a more advanced Graphic User Interface (GUI) is being developed that will make communication with this wireless node system more manageable and one step closer to commercialization. The most important lesson gained from this research is the necessity for a stable wireless communication system in the field that is not affected by interference and a user friendly GUI. The sensor nodes can control irrigation effectively, but are only as effective as the communication with the monitoring system. The other two networks installed in 2008have given the research group additional invaluable information about the dynamics of moisture in both soils and soilless substrates. Various field days at the Wye and Raemelton Farm, together with invited workshop presentations at the American Society of Horticultural Science National conference in Orlando, FL, the International Society of Plant Propagators meetings in Richmond VA and at the National Water Conference in Reno, NV have showcased this research to local and national audiences of growers, scientists and extension professionals.
Publications
- Arguedas F.R., Lea-Cox, J. D, and A. G. Ristvey. 2008. Calibration of Capacitance Sensors to Precisely Measure Water Availability in Soilless Substrates. USDA-CSREES National Water Conference February 3-7, 2008. http://www.usawaterquality.org/conferences/2008/abstract_index.html#A
- Arguedas, F. R. , J. D. Lea-Cox, A. G. Ristvey and D. S. Ross, 2008. Calibration of Capacitance Sensors to Precisely Measure Plant-Available Water in Soilless Substrates. HortScience 43:1097.
- Lea-Cox, J.D., S. Black, A. G Ristvey and David S. Ross. 2008. Towards Precision Scheduling of Water and Nutrient Applications, Utilizing a Wireless Sensor Network on an Ornamental Tree Farm. Proc. Southern Nursery Assoc. Res. Conf. Vol. 53:32-37.
- Lea-Cox, J. D., A. G. Ristvey, F. R. Arguedas and D. S. Ross. 2008. Opportunities and Challenges for Using Wireless Sensor Networks for Ornamental Production. HortScience 43:1069-1070. (Invited Workshop Presentation).
- Lea-Cox, J. D., A. G. Ristvey, F. R. Arguedas, D. S. Ross and G. F. Kantor. 2008. Wireless Sensor Networks for Real-Time Management of Irrigation and Nutrient Applications in the Nursery and Greenhouse Industry. HortScience 43:1103.
- Lea-Cox, J. D., A. G. Ristvey and G. Kantor. 2008. Using Wireless Sensor Technology to Schedule Irrigations and Minimize Water Use in Nursery and Greenhouse Production Systems. Comb. Proc. Int. Pl. Prop. Soc. Vol. 58 (Accepted).
- Lea-Cox, J. D., A. G. Ristvey, F. R. Arguedas Rodriguez, D. S. Ross, J. Anhalt and G. Kantor. 2008. A Low-cost Multihop Wireless Sensor Network, Enabling Real-Time Management of Environmental Data for the Greenhouse and Nursery Industry. Acta Hort. (In Press Nov, 2008).
- Ristvey, A.G., F. R. Arguedas and J. D. Lea-Cox, 2008. Realizing Progressively-Unavailable Water Content in Horticultural Substrates. HortScience 43:1127.
- Ristvey, A.G., J.D. Lea-Cox and F. R. Arguedas. 2008 Smarter Irrigation Management: Wireless Sensor Systems. USDA-CSREES National Water Conference February 3-7, 2008. http://www.usawaterquality.org/conferences/2008/abstract_index.html#R
- Arguedas, F.R, J.D. Lea-Cox and A.G. Ristvey. 2007a. Revisiting the Measurement of Plant Available Water in Soilless Substrates. Proc. Southern Nursery Assoc. Res. Conf. 52:111-115.
- Arguedas, F.R., J. D Lea-Cox and A.G. Ristvey, 2007b. Characterizing Air and Water Content of Soilless Substrates to Optimize Root Growth. Comb. Proc. Int. Pl. Prop. Soc. 57: 103-110.
- Lea-Cox, J. D., G. Kantor, J. Anhalt, A. G. Ristvey and D. S. Ross. 2007. A Wireless Sensor Network for the Nursery and Greenhouse Industry. Proc. Southern Nursery Assoc. Res. Conf. 52:454-458.
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Progress 01/01/07 to 12/31/07
Outputs
Water management in the container nursery industry has been a nation-wide concern since the late 1980's and it remains as important today as it was then. Given the continued expansion of commercial nursery and greenhouse production throughout the US, the proximity of operations to urbanized areas and with the current consumption of water and fertilizers, precision water management technology will play a key role in helping us conserve these resources, and reduce nutrient runoff from these operations. Plants grown in containers, as opposed to soil, present a particular problem since they are generally grown in soilless substrates having limited ability to retain nitrate (NO3) and phosphate (PO42). With limited root volumes in containers, one or more daily irrigations, oftentimes with weekly fertilizations using soluble fertilizers, are required to maximize plant growth. Concern with water use and nutrient runoff have encouraged many greenhouse and nursery operations to
implement "Best Management Practices" (BMP's), to improve irrigation efficiency and reduce nutrient leaching. Individual plant water requirements vary by day and season, depending on any number of environmental and plant developmental factors. Recent research has shown that by making irrigation decisions based on plant need (using time domain reflectometry sensors), that water use and nutrient runoff can be reduced by 60-85% in a nursery system which was open to rainfall. The overall premise of our research is simple; by retaining a greater proportion of irrigated and/or rain water in the plant root-zone (container), water will be conserved, nutrient runoff will be minimized, and plant growth will be maximized. We propose to test and deploy a low-cost wireless irrigation monitoring and control system, for container nursery and greenhouse production systems. We will integrate the monitoring function of Ech20 soil moisture sensors (Decagon Device, Inc.) with the Carnegie-Mellon
University (CMU) wireless networking system, which will enable the real-time monitoring and control (to automatically schedule irrigation events), minimizing water application and nutrient leaching events in both environments. By using the plant to integrate these environmental and growth differences over time and by accurately monitoring the real-time water use of plants with substrate moisture sensors, irrigation water applications can be precisely scheduled automatically. In out-of-ground container operations, where the key to nutrient management is irrigation scheduling, reducing water use and decreasing leaching of nutrients equals reduced overall potential runoff from such intensive growing operations. With the integration of Ech20 moisture sensors to a wireless network, we could revolutionize plant irrigation and nutrient management providing growers with a fully automated irrigation system for precision irrigation control. Through recent extension programming, several members
of Maryland's Green Industry have learned of this research and have expressed interest in attaining this system for their operations.
Impacts
The initial results of this research have shown that this hybrid sensor/communications node system is effective at monitoring container substrate moisture and controlling irrigation based on substrate moisture status. Preliminary data suggest that compared to timed cyclic irrigation, this system can effectively perform efficient irrigation applications utilizing microirrigation. The system applied 30 times less water compared to that of a standard timer based irrigation schedule. Next years study will improve set points to accomodate spring growth and summer irrigation needs. Our researh team has hosted a twilight tour and education program based on this research in October of 2007. We are presently looking for funding to place this system in several commerical nursery operations. This research has not only attracted interest within Maryland's nursery industry, but we have also had regional, national and international invitations to speak at Green Industry conferences
Publications
- Lea-Cox, J.D., A.G. Ristvey, F.R. Arguedas Rodriguez, D.S. Ross, J. Anhalt and G. Kantor. 2008. A low cost multi-hop wireless sensor network enabling real-time management of environmental data for the greenhouse and nursery industry. Acta Hort. (accepted; in press).
- Arguedas, F.R., J. D Lea-Cox and A.G. Ristvey, 2007a. Characterizing Air and Water Content of Soilless Substrates to Optimize Root Growth. Comb. Proc. Int. Pl. Prop. Soc. Vol. 57 (accepted; in press).
- Arguedas, F., J. D. Lea-Cox and A. G. Ristvey. 2007b. Revisiting the measurement of plant available water in soilless substrates. Proc. Southern Nursery Assoc. Res. Conf. vol. 52.(accepted; in press)
- Lea-Cox, J.D., G. Kantor, J. Anhalt, A.G. Ristvey and D. S. Ross. 2007. A wireless sensor network for the nursery and greenhouse industry Proc. Southern Nursery Assoc. Res. Conf. vol. 52. (accepted; in press).
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