干旱区生态环境知识资源中心

Limited precipitation and water shortages are the main concern for winter wheat (Triticum aestivum L.) production in the arid and semi-arid areas of northwest China. The overall goal of this study was to determine the potential for improving winter wheat grain yield and water use efficiency (WUE). The specific objectives were to determine the effect of different irrigation regimes on (1) soil water dynamics, (2) crop growth and development, and (3) evapotranspiration and WUE. Two irrigation experiments were conducted under a rainout shelter and under field conditions during the 2011-2012 and 2012-2013 growing seasons in the Guanzhong Plain. The irrigation treatments consisted of combinations of full irrigation and limited irrigation among the different growth phases. Soil water content, crop growth and development, and yield and yield components were measured. The results showed that the jointing phase was the most sensitive phase to water deficit, followed by the anthesis phase due to a reduction in biomass, yield, and WUE. The decrease in yield was mainly due to a lower number of spikes per unit land area. Deficit irrigation or a higher interval between irrigations at the tillering phase did not significantly (LSD, p < 0.05) affect crop growth and yield, while yield was significantly higher in the treatments that had a high amount of irrigation during the jointing phase. Based on the results obtained from the shelter experiments, it can be concluded that mild water stress during the seeding and tillering phases, sufficient water irrigation during the jointing phase, and mild drying of the soil during the anthesis phase resulted in a high grain yield for the shelter experiment. However, for the field experiment, the high planting density and mild water stress resulted in an increase in yield and WUE. The outcomes of this study can provide a guideline for developing deficit irrigation regimes for maximizing winter wheat production and reducing water use for irrigation in northwest China, especially during water shortages.