Abstract:

To investigate the effect of environmental factors on spring wheat yield in the semi-arid region, the correlation between environmental factors and spring wheat yield was analyzed based on the long-term data (1987—2011) from agrometeorological observation station in Dingxi of Gansu Province. Meanwhile, data about the correlation between water consumption and yield of spring wheat of the study area（1993—2013）were also collected from literature. The results showed that there was a significantly negative correlation between spring wheat yield and the difference between evaporation and precipitation in May and main growth periods. However, the negative correlation was influenced by the soil water content before sowing. The greater the soil water content before sowing, the higher the spring wheat yield was under the same atmospheric evaporation condition, and vice versa. The spring wheat yield had a positive correlation with the precipitation in May and the soil water content before sowing. Under the same precipitation amount, the higher the soil water content before sowing, the higher the spring wheat yield was. Under the same soil water content, the drier the atmosphere in main wheat growth periods, the lower the wheat yield was. The effective water supply could explain 60.4% of the yield variation, and the water consumption could explain 93.4% of the yield variation. Furthermore, the temperature had no direct impact on the spring wheat yield in the study area, but it might affect the spring wheat yield formation through air saturation deficit.

Key words: precipitation, soil water content before sowing, pan evaporation, temperature, air saturation deficit