Influences of deficit irrigation on soil water content distribution and spring wheat growth in Hetao Irrigation District, Inner Mongolia of China

In order to develop a water-saving irrigation system for spring wheat, field experiments were conducted on the deficit irrigation of spring wheat in Hetao Irrigation District, Inner Mongolia. Through measurement of soil moisture content, the spring wheat growth and yield index, the influences of deficit irrigation on soil moisture distribution and spring wheat growth were studied. Results showed that, in the soil layers 0–100 cm below the ground, the soil moisture content under full irrigation at 100% ETc (ETc denotes actual water demanded by crops) and that under deficit irrigation at 80% ETc increased with the increase of soil layer depth; specifically, soil moisture under deficit irrigation at 60% ETc was mainly distributed in the subsurface layer (20–40 cm) and the middle layer (40–60 cm). The spring wheat yield was not greatly influenced by the deficit irrigation at 80% ETc, showing a decrease of merely 5–13% compared with that under full irrigation, while deficit irrigation at 60% ETc had greater impact on the growth and yield of spring wheat, cutting the yield by 10–37% in comparison with that under full irrigation. In the study area, the deficit irrigation treatment at 80% ETc was adopted, wherein the irrigation norm in the growth period was 288 mm. This irrigation system had little adverse impact on spring wheat growth and yield, and therefore, water-saving irrigation could be realized.