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John C. Majsztrik, Elizabeth W. Price and Dennis M. King

We describe and estimate the potential environmental benefits associated with the adoption of wireless sensor irrigation networks (WSIN) in United States ornamental crop production. Benefit estimates are based on results from on-farm research conducted during the previous three years, using both conservative and optimistic assumptions about the levels of WSIN technology adoption. We project reductions in water use and air and water emissions for six U.S. agricultural regions, the U.S. overall, and the six states that make up the Chesapeake Bay watershed. Based on these analyses, an average nationwide WSIN adoption rate of 50% in ornamental operations would result in annual water use savings of ≈223 billion liters (enough for 400,000 U.S. households annually) or a 25% reduction in total water use for all ornamental production. Reductions in annual carbon dioxide emissions, assuming only the reduced energy use from pumping less water was 36,232 Mg (equivalent to removing 7500 cars annually). Reduced fertilizer applications and more efficient irrigation resulted in reductions of 282,000 kg nitrogen and 182,000 kg phosphorous. These efficiency gains and nutrient discharge reductions have been shown to generate significant profits for growers, but would cost hundreds of thousands of dollars to achieve using conventional urban or agricultural best management practices (BMPs). If WSIN technologies are adopted in other areas of specialty horticulture (e.g., fruit, vegetable, and nut production) or in agronomic crops [e.g., corn (Zea mays) and wheat (Triticum sp.)], the indirect and induced private and environmental benefits will likely be much higher. Since the environmental benefits of WSIN technologies depend critically on adoption rates, we also briefly describe potential pathways to increase WSIN adoption such as providing technical assistance or offering financing or loan guarantees.

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John D. Lea-Cox, William L. Bauerle, Marc W. van Iersel, George F. Kantor, Taryn L. Bauerle, Erik Lichtenberg, Dennis M. King and Lauren Crawford

Wireless sensor networks (WSNs) transmit sensor data and control signals over long distances without the need for expensive infrastructure, allowing WSNs to add value to existing irrigation systems since they provide the grower with direct feedback on the water needs of the crop. We implemented WSNs in nine commercial horticulture operations. We provide an overview of the integration of sensors with hardware and software to form WSNs that can monitor and control irrigation water applications based on one of two approaches: 1) “set-point control” based on substrate moisture measurements or 2) “model-based control” that applied species-specific irrigation in response to transpiration estimates. We summarize the economic benefits, current and future challenges, and support issues we currently face for scaling WSNs to entire production sites. The series of papers that follow either directly describe or refer the reader to descriptions of the findings we have made to date. Together, they illustrate that WSNs have been successfully implemented in horticultural operations to greatly reduce water use, with direct economic benefits to growers.