Using Wireless Sensor Networks for Irrigation and Nutrient Management in Strawberry Production

Increasing the efficiency of water and fertilizer resources used in strawberry production is vital as evidenced by the serious water shortage affecting growers in California and regulations limiting nutrient runoff from agricultural operations in mid-Atlantic region such as Maryland. Sensor networks have the potential to be successfully applied in order to achieve these goals for an economically and environmentally sustainable strawberry production. We have installed sensor networks on two commercial strawberry farms in Maryland to provide the growers real-time data on environmental conditions and soil moisture and electrical conductivity levels that can be used to make better irrigation and nutrient management decisions. Sensor-controlled irrigation is implemented in production beds on the farms with the objective of quantifying its effect on plant growth, yield, fruit quality and irrigation water use as compared to current practices followed by growers (grower-controlled irrigation). The sensor-controlled irrigation is implemented by control nodes that start irrigation events whenever average real-time volumetric water content (VWC) readings in the root zone drop below user-defined (set-point) soil moisture levels. Irrigation water applications are continuously measured using flow meters to compare the two irrigation treatments whereas soil electrical conductivity data are being collected at two depths to estimate nutrient leaching below the root zone. Continuous data from soil moisture, electrical conductivity sensors, environmental sensors, and flow meters installed at the farms is collected by Em50R and nR5 data loggers (Decagon Devices, Inc., Pullman WA) and transmitted to a basestation computer. Using software (Mayim LLC, Pittsburgh, PA), the real-time data is organized and accessed by growers and researchers on any internet enabled device. We are conducting a replicated field study to compare deficit irrigation treatments and a control in a plasticulture strawberry production system, using wireless sensor network to implement sensor-controlled irrigation based upon real-time VWC and soil water potential data. Irrigation water volumes are continuously measured using flow meters to compare irrigation water use efficiencies for the deficit irrigation and control treatments. Plant growth, fruit yield and fruit quality data are being collected and will be analyzed to identify optimum deficit irrigation levels.