Comparison of precision and conventional irrigation management of cotton and impact of soil texture

E Vories,M Andrade,S Drummond,S Evett,K Sudduth,S O’Shaughnessy

doi:10.1007/s11119-020-09741-3

Abstract

Soil textural variability diminishes the effectiveness of conventional irrigation management. 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 2016 and 2017 with the objective to compare yield and irrigation water use efficiency among three water-management treatments for cotton: rainfed, irrigated based on the USDA-ARS Irrigation Scheduling Supervisory Control And Data Acquisition (ISSCADA) system, and irrigated based on a water balance method. Sand content in the top 533 mm soil layer was estimated from apparent electrical conductivity (ECa). Yield values measured near an ECa observation were averaged to create a data set containing sand content and associated yield. Although the trend was for the rainfed treatment to have the lowest yield in both years, the yield differences among all treatments were not significant when sand content was not considered. A strong effect of sand content on cotton yield was observed in both seasons, although the slopes differed among the water management treatments in 2016. The ISSCADA system tended to have a higher irrigation water use efficiency in both seasons, but the difference was not significant in 2016 when total irrigation applications were low. 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.

Highlights

Irrigated agriculture in the USA is a major consumer of freshwater, accounting for approximately 80% of the nation’s consumptive water use (Schaible and Aillery 2015)
The specific objectives of this study were to compare the yield of rainfed cotton and irrigated cotton based on the Irrigation Scheduling Supervisory Control And Data Acquisition (ISSCADA) system and on the Arkansas Irrigation Scheduler (AIS), to compare the irrigation water use efficiency (IWUE) of the cotton between the two irrigation scheduling methods, and to investigate the impact of soil texture and variability on the irrigation response
The Arkansas Irrigation Scheduler (AIS) method recommended a uniform irrigation application based on an estimated soil water deficit, while the USDA-ARS Irrigation Scheduling Supervisory Control And Data Acquisition (ISSCADA) system made site-specific recommendations based on an integrated crop water stress index

Summary

Introduction

Irrigated agriculture in the USA is a major consumer of freshwater, accounting for approximately 80% of the nation’s consumptive water use (Schaible and Aillery 2015). Vories and Evett (2014) reported that while irrigated land in the US increased by 3.5 Mha (19%) from 1988 to 2008, the increase in the US Mid-South over the same period was 1.2 Mha (71%). The increase is related to the fact that with supplemental irrigation, crop yields attain on average 80% of potential yield in humid and sub-humid areas while rainfed crops attain on average 50% of potential yield (Lobell et al 2009). Uncertainty in the amount and timing of precipitation is one of the most serious risks to crop production in those areas and timely irrigation has been shown to increase yields of cotton (Sui et al 2017; Vories et al 2007). Producers have become increasingly reliant on irrigation to ensure adequate yields and reduce production risks

Objectives

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Results

Conclusion