Advances in irrigation management tools: The development of ARSmartPivot

Abstract

Abstract. Scientists with the USDA-ARS Conservation & Production Research Laboratory, Bushland, TX, have developed and patented an Irrigation Scheduling Supervisory Control and Data Acquisition System (ISSCADAS, patent ser. no. 61/513,767). The ISSCADAS assists irrigation management by automating the collection of data from plant sensing systems, as well as applying algorithms to process those data. This paper describes advances in the development of software, ARSmartPivot (ARSP), for the operation of the ISSCADAS. Besides serving as a communication port between users, sensors, and center pivots, ARSP includes decision support tools that enhance irrigation management. For example, mathematical algorithms were implemented into ARSP‘s computational engine to generate recommended prescription maps. In the summer of 2014, ARSP was applied to the automatic control of a center pivot equipped for Variable Rate Irrigation (VRI). One-half of a six-span center pivot field was planted with two corn hybrids (Pioneer ® P0876HR and 33Y75). Irrigation management of both hybrids was accomplished using two irrigation scheduling methods: an automatic control based on a plant feedback system and a manual control based on the neutron probe. Three irrigation levels were applied in the experiment for both types of control: 100%, 75%, and 50%. Automatic plots were irrigated if a mean integrated crop water stress index (iCWSI) calculated for the automatic 100% plots for each hybrid was above a pre-determined threshold (based on well-watered corn in Bushland). For the P0876HR hybrid, average corn yields for automatic plots were 1.48 to 1.86 kg m-2 and 1.35 to 1.72 kg m-2 for manual plots. For the 33Y75 hybrid, average corn yields for automatic plots were 1.47 to 1.91 kg m-2 and 1.62 to 1.83 kg m-2 for manual plots. Total water use amounts for the P0876HR hybrid were 549 to 759 mm for automatic plots and 513 to 632 mm for manual plots. For the 33Y75 hybrid, the corresponding amounts were 587 to 824 mm for automatic plots and 548 to 749 mm for manual plots. The ARSP software managed irrigation scheduling of the automatic plots by combining the operation of the ISSCADAS and the center pivot system.