Effects of deficit irrigation on physio-ecological indices of winter wheat

Water shortage is the main limitation to agricultural productivity in the North China Plain — a main grain production base in China. It has therefore been a major research task to develop an agricultural production practice that uses limited fresh water resources in the region. Deficit irrigation is a new irrigation scheme that optimally uses water resources while maintaining high economic yield. This paper reviewed the effects of deficit irrigation on physio-ecological indices of winter wheat at the Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences. Field plot irrigation experiments had shown that different levels of deficit irrigation at different growth stages of winter wheat affected root size and distribution in the soil profile, canopy structure, biomass growth, grain yield, and water use efficiency. The experiments showed that different levels of deficit irrigation facilitated leaf stomata adjustment which in turn affected the photosynthetic products and distributions of dry matter. The highest grain yield was obtained under optimal deficit irrigations at the different growth stages. This implied that the levels of deficit irrigation were different at different growth stages of winter wheat. The deficit sensitivity index was highest at jointing stage, when was not suitable time for deficit irrigation. In other words, deficit irrigation at other growth stages like the recovering and grain-filling stages little affected grain yield and therefore resulted in high water use efficiency. Based on the above results, an optimal irrigation scheme was developed in relation to the trend in precipitation leveling the region — i.e., 1, 2 and 3 times of irrigation at about 60~70 mm every time in wet years, normal years and dry years, respectively. The optimal irrigation scheme had been widely used in the North China Plain region.