To investigate the mechanism of the coupled effects of precipitation, nitrogen (N) fertilizer, and straw mulching on dryland spring wheat yield under different precipitation year types, the APSIM model was calibrated using spring wheat yield, soil, and meteorological data under no-tillage and no-tillage with straw mulching from 2013 to 2018. Combined with historical data from 1970 to 2022 to drive the calibrated model, yields were simulated under 5×5×5 combinations of precipitation changes (±20%, ±10% and 0%), nitrogen application rates (0.0, 52.5, 105.0, 157.5, and 210.0 kg/ha), and straw mulching rates (0, 1125, 2250, 3375, and 4500 kg/ha). The coefficient of variation of yield under single-factor was analyzed for each year type, and quadratic orthogonal polynomial stepwise regression, single-factor analysis, and interaction effects were employed to study the impacts of various factors on yield. The results showed that the APSIM model performed well, with R² > 0.8, NRMSE < 10%, and ME > 0.8 for both tillage practices. In dry, normal, and wet years, the individual and interactive effects of the three factors all positively influenced yield, with the order of effect intensity being: precipitation change > nitrogen application rate > straw mulching rate. Based on the natural precipitation of the current year, the optimal yields and cultivation measures for each year type were as follows: in dry years, an optimal yield of 2203.65 kg/ha was achieved by increasing precipitation by 20%, applying 153.13 kg/ha of nitrogen, and mulching with 4500 kg/ha of straw; in normal years, an optimal yield of 2838.77 kg/ha required a 20% increase in precipitation, 170.76 kg/ha of nitrogen, and 4500 kg/ha of straw mulching; in wet years, an optimal yield of 3447.11 kg/ha required a 20% increase in precipitation, 188.58 kg/ha of nitrogen, and 4500 kg/ha of straw mulching. In conclusion, within the simulated experimental range, increasing precipitation, nitrogen application rate, and straw mulching amount under no-tillage conditions can enhance the simulated yield of spring wheat, but the degree of impact varies with precipitation year types. For local spring wheat, water, fertilizer, and mulching strategies should be formulated according to the specific year type to achieve high and stable yields.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |