Optimizing irrigation for winter wheat to maximize yield and maintain high-efficient water use in a semi-arid environment

Optimizing irrigation scheduling is vital in maintaining high crop yield and sustainable water use in waterlimited regions worldwide. In this study, a 4-year field experiment (2016-2020) was conducted to evaluate the effect of six irrigation schedules on the grain yield performance, soil water content, plant evapotranspiration, and irrigation water use efficiency of typical winter wheat production system in the North China Plain. The six irrigation schedules involved irrigation at different growth stages, including one critical growth stage (60 mm per stage, I60), two stages (I120), three stages (I180), four stages (I240), and five stages (I300). No irrigation was performed in the control field (I0). The results showed that the plant height and yield components of winter wheat (spike number per hectare, kernels per spike, thousand-kernel weight) increased with the increase in annual irrigation amount. The grain yield in each study year increased quadratically (P < 0.05) with the annual irrigation amount. The soil water content in the 0-90 cm soil layer (where the wheat roots are mainly distributed) increased significantly during the growing season with the increase in annual irrigation amount. In I240, the mean soil water content (0-90 cm) during the growing seasons (17.3-22.6 %) was 61.7-80.8 % of the field water holding capacity, sufficiently favoring wheat growth. The average soil water storage (0-90 cm) during the wheat growing season ranged from 241.1 to 283.2 mm in the irrigation applied treatments, which were 21.7-63.8 mm (9.9-29.1 %) higher than in no irrigation treatment (I0, 219.4 mm). The 4-year averages of wheat grain yield did not differ significantly between I240 (7909.1 kg ha-1) and I300 (7868.6 kg ha-1); however, the average irrigation water use efficiency decreased from 33.0 kg ha-1 mm-1 in I240 to 26.2 kg ha-1 mm-1 in I300. Therefore, we recommend an irrigation scheduling at the regreening, jointing, flowering, and filling stages (I240, 60 mm per stage, 240 mm in total) to maintain high grain yield and sustainable soil water use for winter wheat production in the North China Plain and similar semi-arid regions.

Automated summary

This study conducted a 4-year field experiment to determine an optimal irrigation schedule for typical winter wheat production system in the North China Plain, recommending irrigation at specific growth stages to increase yield and maintain sustainable soil water use.