Unraveling the regional dynamics of straw mulching and incorporation on crop yields in Northeast China

Abstract

Selecting an appropriate straw return method is crucial for enhancing crop productivity and promoting sustainable agriculture in the black soil region of Northeast China. However, few studies have evaluated the effectiveness of different straw return methods on crop yield, and their regional applicability has not yet been established. This study integrates machine learning approaches and meta-analysis to assess the impact of straw mulch (SM) and straw incorporation (SI) on crop yields under varying climate, soils, and agricultural management conditions in Northeast China’s drylands. Straw return overall increases crop yield by ∼5 %, among which SM and SI have similar mean contributions to yield improvements (5 % vs 4 %). The effects of two straw return methods vary with environmental conditions; specifically, SM outperforms SI under low temperatures (mean annual temperature MAT <6 ℃), drought (mean annual precipitation MAP <600 mm), and moderate erosion (mean annual soil erosion ASE 0.5–2 t/ha), but SI has better effects with high temperatures (MAT >6 ℃), high precipitation (MAP >600 mm), and severe erosion (ASE >2 t/ha). SM achieves the highest yield benefit (8 %) under moderate straw return amounts (6000–10,000 kg/ha), whereas SI performs the best (6 %) at low straw return amounts (< 6000 kg/ha). Furthermore, the yield-enhancing effects of both methods intensifies with increasing experimental duration, with SI's effect gradually and consistently surpassing that of SM. Spatial prediction results reveal that the overall extent of yield increase for SI is 9 %, with higher increasing yield potential observed in the southwest and southeast regions, while the extent of yield increase for SM is lower, at only 3 %. This study elucidates the differentiated yield-enhancing effects of different straw return methods in the black soil region, providing a scientific basis for precision agricultural management and sustainable utilization of black soil in Northeast China and other similar regions.