The Responses of Maize Yield and Water Use to Growth Stage-Based Irrigation on the Loess Plateau in China

Abstract

Water scarcity is the major limiting factor to crop production in arid and semi-arid regions. Better understanding the response of crops to the time and intensity of water stress at different growth stages is helpful to optimize irrigation scheduling under water limited conditions. A 4-year (2013–2016) field experiment was conducted at Yangling on the Loess Plateau, to quantify the effects of timing and intensity of water stress on yield, actual evapotranspiration (ETa) and water use efficiency (WUE) of summer maize, and to identify the most sensitive stage of maize to water stress. Two deficit irrigation levels, i.e. 70 mm and 110 mm, were considered. For each irrigation level, irrigation was applied for any three of four key growth stages of maize: seedling (D1), jointing (D2), tasseling (D3) and grain filling (D4). The results showed that: (1) water stress at vegetative growth stages had higher yield response factors than that at reproductive growth stages, indicating the former tended to have greater effects on maize yield; (2) although maize yield increased linearly with ETa, the variations of yield and WUE with changed ETa were not synchronous. Low-level irrigation should be applied in the regions with severe water shortage to obtain the maximum WUE, while in regions with more water a crop can be irrigated based on sufficient irrigation scheduling; (3) the contour map of Yield-ETa-WUE indicated a greater effect of yield on WUE than that of ETa on WUE. When irrigation water is limited, high WUE can be achieved if it is applied at vegetative growth stages, while high yield can be achieved if more available water is applied at tasseling stage. Therefore, in order to develop a sustainable irrigation scheduling on the Loess Plateau, water availability and agriculture production goals (high WUE or high yield) should be taken into account together.