Study on the effects of long-term no-tillage straw mulching on wheat yield improvement in dryland areas based on the APSIM model

Traditional rotary tillage and plowing practices often lead to water and nutrient loss in dryland farming regions. Investigating the effects of minimum and no-tillage practices on soil moisture and wheat yield in dryland systems is therefore crucial for water conservation and yield stability. This study conducted two growing seasons of dryland wheat experiments in Yaodu district, Linfen city, Shanxi province, using two tillage methods: no-tillage with straw mulching (NT) and rotary tillage with straw incorporation (RT). The wheat variety used was “Jinmai 102”. The APSIM-Wheat model was calibrated and validated using observed data on soil water storage, biomass, and yield at various growth stages. The validated model was then employed to simulate the growth, soil moisture dynamics, and yield of winter wheat over 39 years of historical meteorological data in Yaodu. The impacts of different annual precipitation patterns and tillage methods on wheat yield, soil water storage, and water use efficiency (WUE) were analyzed. Compared with rotary tillage, no-tillage with straw mulching increased wheat yield by 31.1%, 21.0%, and 28.5% in normal, wet, and dry years, respectively. During the fallow period, soil water retention improved by 26.6%, 35.9%, and 37.5%, and WUE increased by 29.0%, 10.0%, and 9.9%, respectively. However, there was no significant difference in evapotranspiration during the wheat growing period between the two tillage methods. Under treatment NT, wheat yield was significantly positively correlated with both fallow-period and annual precipitation. Moreover, under NT, yield was significantly correlated with soil water retention during the fallow period, whereas no such correlation was observed under RT. Overall, no-tillage with straw mulching enhances dryland wheat yield on the Loess Plateau primarily by improving soil water retention during the fallow period, making it an effective tillage strategy for yield stability in this region.