Objective Studying the soil fertilization and yield increasing mechanism under the rotation of winter wheat and spring corn 3-1 in the eastern part of Gansu Province can be used to support green, sustainable and efficient production of dryland crops.

Methods This study is based on a long-term positioning experiment of tillage and fertilization in dryland soil set up in Zhen yuan County, Qingyang City, Gansu Province in 2005. This study is a two-factor experiment, with tillage as the main treatment and fertilization as the secondary treatment, to analyzes the yield and water effects of long-term cultivation and fertilization in a 17-year rotation system of wheat and jade, as well as the mechanisms of soil fertilization and sustainable yield increase. The tillage treatment includes traditional tillage and no tillage, while the fertilization treatment includes no fertilization (CK), single nitrogen fertilizer (N), single phosphorus fertilizer (P), single farmhouse fertilizer (M), nitrogen fertilizer combined with phosphorus fertilizer (NP), and NP combined with organic fertilizer (NMP). Combining analysis of wheat and maize yields, this study explores the mechanisms of crop yield differences across rainfall years under tillage and fertilization treatments.

Results The results indicate that different rainfall years, tillage, and fertilization methods significantly affected the yields of wheat and maize. Under different precipitation patterns and tillage methods, the NMP treatment yields (winter wheat 3441 kg/hm², spring maize 8991 kg/hm²) were significantly higher than those of other fertilization treatments, with a more obvious effect of NMP treatment on crop yields under wet years . in wet year, Compared to conventional tillage, no-tillage significantly reduced crop yields during drought years and wheat yields during normal rainfall years. In wet years, no significant difference is observed in crop yields between traditional tillage and no-tillage treatments. However, in drought and normal years, the average yield of winter wheat decreases by 15.6% and 25.7%, respectively, and maize yields decrease by an average of 17.9% and 4.6%.Compared to conventional tillage, no-tillage decreased wheat and maize seasonal water use efficiencies by 6.7% and 17.0% in drought years, and wheat seasonal water use efficiencies decreased by 24.0% in normal rainfall years, while there was no significant difference in well-watered years. In contrast, soil organic matter, total nitrogen, total potassium, alkaline dissolved nitrogen, Olsen-phosphorus and available potassium contents were significantly higher under no-tillage than under conventional tillage treatments.

Conclusion These results suggest that the yield reduction caused by no-tillage is due to differences in crop water use efficiency rather than soil nutrient differences. In summary, tillage managements for rain-fed agriculture on the dryland loess plateau with black soil in eastern Gansu should be selected based on rainfall conditions, so as to improve the yield stability and sustainability of crops in this region. This knowledge provides a theoretical basis for the efficient use of precipitation and stable high yield in dryland farming in eastern Gansu.