Defining Irrigation Scheduling Based on Crop Water Stress Index and Physiological Parameters for Hybrid Corn in Semi-Arid Climate

Abstract

The goal of this study is to determine the crop water stress index (CWSI) and irrigation scheduling based on CWSI values, as well as to examine the correlations between CWSI, physiological parameters and grain yield of corn hybrid P31A34 in semi-arid climate conditions. In 2014 and 2015, the upper limit (UL) temperatures at which plants were entirely exposed to water stress were at 1.178°C and 2.38°C respectively. When the corn grain yield began to decline, the CWSI threshold value was 0.34, indicating the yield limit. Grain yield, crop water consumption, crop water stress index, chlorophyll content, water use efficiency and leaf area index were found to have negative correlations (p ≤ 0.01) with CWSI values in both years of the study. The findings revealed that in semi-arid climate conditions, a maximum of 30% water deficit can be used during the growing period of the corn compared to full irrigation (I100) for water savings, and that water deficits greater than 30% result in considerable grain yield losses. In areas where water resources are limited, the moderate water deficit (I70) may be a viable alternative to the I100.