Subsoil water use to attain stable high yields of winter wheat in drylands Loess Plateau of China

Abstract

In drylands, rainfed crops generally produce low yield due to low and irregular annual precipitation. It is challenging to obtain both high and stable crop yield in drylands. Soil water storage and consumption are crucial affecting crop yield in drylands. However, the relationship between yield and the degree of subsoil water consumption is still unclear. To clarify the contribution of subsoil water on yield performance under different conditions of WS (water supply during the growing season), we analyzed the relationship between grain yield of winter wheat and SWC1–2 (1–2 m subsoil water consumption) under different WS conditions, from published studies on a typical dryland habitat (Loess Plateau of China). The results showed that increasing SWC1–2 during late growth stage had a great potential to increase wheat yield. Moreover, the probability of low wheat yield decreased as more subsoil water was used. When the residual subsoil water storage reduced from (270–210) to (150–90) mm at harvest time, the probability of yield falling below 4000 kg ha−1 was decreased from 100 % to 48.01 % under < 666 mm WS conditions; and the probability of exceeding 5000 kg ha−1 was greatly increased from 0.55 % to 99.59 % under > 666 mm WS conditions. In addition, SWC1–2 was significantly increased with increasing number of spikes or shoot biomass, which suggests that it is necessary to ensure a sufficient plant population for higher consumption of subsoil water. Our study indicates that wheat yield can be greatly enhanced by using more subsoil water under high WS conditions, and the probability of low wheat yield can be decreased with increasing subsoil water consumption under low WS conditions.