Advances in precision irrigation management of cotton

Authors: Vories, Earl; Oshaughnessy, Susan; Evett, Steven - Steve; ANDRADE, MANUEL - University Of Nevada

Submitted to: National Irrigation Symposium
Publication Type: Proceedings
Publication Acceptance Date: 6/30/2020
Publication Date: 12/6/2021
Citation: Vories, E.D., Oshaughnessy, S.A., Evett, S.R., Andrade, M. 2021. Advances in precision irrigation management of cotton. Proceedings of 6th Decennial National Irrigation Symposium, December 6-8, 2021, San Diego, California. Paper No. 20-134. https://doi.org/10.13031/irrig.2020-134.
DOI: https://doi.org/10.13031/irrig.2020-134

Interpretive Summary: Irrigated agriculture accounts for the majority of the consumptive water use in the US and soil textural variability within many irrigated fields diminishes the effectiveness of conventional irrigation management. Benefits of variable-rate application of other agricultural inputs can be reduced by applying inappropriate amounts of water. A field study was conducted by ARS scientists from Portageville, Missouri, and Bushland, Texas, at the University of Missouri Fisher Delta Research Center Marsh Farm at Portageville in 2019. The objective of the research was to compare rainfed cotton and cotton irrigated based on the USDA-ARS Irrigation Scheduling Supervisory Control And Data Acquisition (ISSCADA) system. Frequent rainfall for most of the growing season greatly affected the study and differences in crop growth were apparent before irrigation was required. While some of the ISSCADA-managed plots received irrigation recommendations, they were for quite late in the season and there was little opportunity to recover from early-season detrimental effects. The study is continuing at Portageville and other locations and the ISSCADA system is constantly being improved to better meet the needs of agricultural producers.

Technical Abstract: Soil textural variability diminishes the effectiveness of conventional irrigation management and can reduce the response of site-specific application of agrochemicals and fertilizer. Variable rate irrigation (VRI) can address soil variability; however, users need guidance to prepare prescriptions for optimal water application. A study was conducted at Portageville, MO, USA, in 2019 in a cotton field with highly variable soil with the objective to compare the yield of rainfed cotton, irrigated cotton with scheduling based on the Irrigation Scheduling Supervisory Control And Data Acquisition (ISSCADA) system using infrared thermometers (IRTs) only, and on the ISSCADA system using both IRTs and soil moisture sensors. Frequent rainfall for most of the growing season greatly affected the study and differences in crop growth were apparent early in the season, long before irrigation was required. The plots with irrigation based on IRTs only never received an irrigation recommendation in 2019. While some of the plots with irrigation scheduled based on both IRTs and soil moisture sensors received irrigation recommendations, the earliest was 6 August. Therefore, there was little opportunity to recover from early-season detrimental effects, resulting in no significant yield differences between the treatments. The study is continuing at Portageville and other locations and the ISSCADA system is constantly being improved to better meet the needs of agricultural producers.