Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 5/12/2006
Publication Date: N/A
Interpretive Summary: This paper evaluates the performance, limitations, and transferability of a new integrated wireless system to monitor and control variable rate applications remotely on a continuous move irrigation system. The system varies water application rate by pulsing nozzles controlled by solenoids connected via relays to a single board computer. The system monitors the irrigation system flow, pressure, position and any sensors installed in the soil, crop or wireless weather station. The system was installed on two spans of a linear move irrigation system at the WSU Irrigated Agriculture Research and Extension Center in Central Washington and on two spans of a Valley full size Lateral Move in the Nesson Valley, North Dakota. Tests were conducted in the months of June, August and September. For the Nesson Valley system a quadratic pattern was imposed pulsing banks of nozzles along the Lateral Move travel direction on 12 m long irrigation blocks. Standard catch can tests were performed at the middle of the irrigation pattern blocks, at the blocks boundaries and for the typical Lateral Move sprinkler application pattern. Soil water content was measured either with sensors reporting 15 minute data or gravimetrically periodically. The coefficient of uniformity of the linear move system was determined as well as different sources of errors.
Technical Abstract: Precision irrigation systems can have inherent errors that affect the accuracy of variable water application rate and affect the transferability of the control system. The objective of this paper was to assess the performance, and transferability of a remote irrigation monitoring and control system (RIMCS) designed for precision water management on continuous move irrigation systems. The RIMCS varies water application rate by pulsing nozzles controlled by solenoids connected via relays to a single board computer (SBC) with wireless Ethernet connection to a remote server. The system also monitors irrigation system flow, pressure, and position and accommodates wireless sensor networks installed in the field. The system was installed on a linear move (LM) irrigation system in the lower Yakima Valley of eastern Washington State and on a LM in the Nesson Valley of western North Dakota. For the Washington LM, four pre-defined irrigation patterns were imposed under each of two spans and variable rates were applied as a percentage of the nozzle base application rate. Each nozzle was pulsed to create the intended irrigation pattern across the span length and along the LM travel direction. Tests were conducted in the months of June, August and September 2005. For the North Dakota LM, a quadratic pattern was imposed pulsing banks of nozzles along the LM travel direction. Standard catch can tests were performed at the middle of the irrigation pattern blocks, at the blocks boundaries and for the typical LM sprinkler application pattern. The system performance was evaluated using catch can water depth error assessment when compared to set target values. Variable water application depths using the RIMCS created the target application patterns with application accuracies in the range of uniform application uniformity coefficients of 88 - 96%. The RIMCS was successfully transferred to another LM in North Dakota.