Maize straw application shows regional-scale improvements to soil fertility and crop yields in Chinese croplands: A meta-analysis

Applying maize straw to agricultural land is recognized as a crucial practice for enhancing soil fertility and crop yields. However, the significant regional variations in the impacts of maize straw on soil properties and crop yields remain poorly understood, particularly under the diverse climatic and soil conditions found across China. This study aimed to quantify the effects of maize straw application on soil fertility and crop yield and to identify how climatic factors, initial soil properties, and straw application rates influence these effects across different regions of China. A meta-analysis was conducted using data from 94 peer-reviewed studies covering 1187 data pairs for sites throughout China. This analysis assessed the impact of maize straw application on key indicators of soil fertility, including soil organic carbon (SOC), total nitrogen (TN), and soil bulk density, as well as on crop yield. Statistical models were used to evaluate the relationships between climatic conditions, initial soil fertility, straw application rates, and resulting outcomes. Maize straw application significantly increased crop yield, SOC, and TN, whereas soil bulk density was reduced. Climatic conditions and initial soil properties notably influenced these outcomes. Regions with moist and cool climates exhibited the most pronounced gains in SOC and productivity. Furthermore, with increasing temperatures from high-latitude regions to low-latitude regions, benefits in crop yield, TN, urease, sucrase, and organic matter decreased. Maximum improvements in crop yield were obtained under higher straw application rates (> 9000 kg ha⁻¹ yr⁻¹). Importantly, significant enhancements in crop yield, SOC, and TN were achieved by applying maize straw in areas with initial SOC and TN levels below 6 g kg −1 and 1 g kg −1 , respectively. Maize straw application effectively enhances soil fertility and crop yields in cropland in China. Specific benefits are dependent on regional climate, initial soil fertility, and application rates. These findings highlight the importance of adjusting straw application practices to local environmental conditions to achieve optimal agricultural productivity and soil health. The results of the comprehensive regional analysis conducted in this study underscores the role of environmental and management factors in maximizing the benefits of maize straw application. The insights gained can inform the development of tailored straw application practices that enhance both agronomic and ecological benefits, contributing to sustainable crop management in China and potentially other regions with similar agricultural conditions. • Maize straw application increased soil organic carbon, total nitrogen, and clip yield. • Straw return most effectively increases organic carbon and crop yield in cool, moist climates. • Increases in crop yields under straw returning exceeded those under straw mulching. • Straw application disrupts the C:N balance, boosting urease activity and raising soil nitrogen demand. • Straw return significantly increased the fertility of barren and problematic soils.