Effects of minimum or no-tillage system and straw returning on extreme soil moisture and yield of winter wheat

Soil moisture and yield of winter wheat were evaluated in a field experiment involving tillage (conventional tillage, subsoiling, harrowing, rotary tillage, and no-tillage) plus straw application (straw returning and no-straw returning) under a rotation of wheat and maize, and the aim was to utilize rainwater effectively and alleviate the deficit of water resources in agriculture. The results showed that subsoiling improved soil moisture in the period of waterabundance and yield of winter wheat under straw returning and no-straw returning over conventional tillage, especially subsoiling tillage plus straw returning, which enhanced by 25.74% and 11.45% over conventional tillage, respectively. Straw factor played a leading role in soil moisture in the period of water abundance, both straw factor and tillage factor played important roles in soil moisture in the period of water deficit and yield of winter wheat. The interactive effects between no-tillage, subsoiling, harrowing and straw returning improved rainwater collection and winter wheat yield. The results also show that yield of winter wheat is not closely related with soil moisture in the period of water deficit, however, significantly relates with soil moisture in the period of water abundance.