Winter Wheat Evapotranspiration Estimation under Drought Stress during Several Growth Stages in Huaibei Plain, China

Yi Cui,Shangming Jiang,Juliang Jin,Ping Feng,Hongwei Yuan

doi:10.3390/w10091208

Abstract

Estimating crop evapotranspiration under drought stress provides the theoretical foundation for optimizing irrigation schedule and reducing agricultural drought risk. Winter wheat water deficit plot experiments were conducted based on large-scale weighing lysimeters in the Huaibei Plain. The response of evapotranspiration to water deficit during several growth stages was analyzed; four crop coefficients were optimized and then evapotranspiration under drought stress was estimated with the dual crop coefficient method and the genetic algorithm. Drought stress not only reduced evapotranspiration during the current stage, but this influence was also transferred to the following periods. Evapotranspiration could basically return to the normal status after rewatering if the plant did not previously suffer from serious drought stress. Therefore, severe water deficit during continuous wheat growth periods should be avoided, and the deficit intensity during each stage should be controlled. The optimized Kcb ini, Kcb mid, Kcb end and Kc max were 0.32, 1.38, 0.33 and 1.39, and the root mean square error, mean absolute error, and mean relative error of the corresponding estimated evapotranspiration under drought stress were 22.83%, 25.36%, and 11.78% less than those using recommended coefficients, respectively. These optimized crop coefficients provide references for the practical application in the Huaibei Plain, this method for estimating crop evapotranspiration under drought stress can be applied to field circumstances and other regions.

Highlights

Winter wheat is one of the main food crops in Anhui Province, China, and its perennial cultivated area is greater than two million hectares, and that in the Huaibei Plain accounts for approximately 70%
The Huaibei Plain is located in a transitional zone of high and low latitudes with northern and southern climates [2], and its spatiotemporal distribution of precipitation is uneven, which results in frequent agricultural drought disasters
This study aims to discuss the winter wheat evapotranspiration response to drought stress during multiple growth periods and the compensation mechanism that occurs after rewatering, and to establish an applicable method for estimating crop evapotranspiration under drought stress conditions in field circumstances

Summary

Introduction

Winter wheat is one of the main food crops in Anhui Province, China, and its perennial cultivated area is greater than two million hectares, and that in the Huaibei Plain accounts for approximately 70%of the total area. Winter wheat is one of the main food crops in Anhui Province, China, and its perennial cultivated area is greater than two million hectares, and that in the Huaibei Plain accounts for approximately 70%. Plain belongs to the Huang-Huai winter wheat district [1], with a total annual yield of winter wheat that occupies approximately 8% of the national production; it is one of the most important winter wheat planting areas in China. Deeply analyzing the response of winter wheat evapotranspiration to water deficit during several growth stages while accurately estimating the amount of evapotranspiration under drought. Water 2018, 10, 1208 stress is of great significance to formulating a reasonable irrigation program, improving water use efficiency and guaranteeing a high and stable yield of winter wheat in the Huaibei Plain [5,6]. Chen et al [11]

Objectives

Methods

Results