The Responses of Crop Yield and Greenhouse Gas Emissions to Straw Returning from Staple Crops: A Meta-Analysis

The practice of straw returning to agricultural fields (SRF) affects crop yields and greenhouse gas (GHG) emissions. However, the responses of crop yields and GHG emissions vary significantly due to diverse climatic conditions, soil conditions, and field management practices. In this study, we conducted a meta-analysis to assess the effects of SRF on the crop yield and GHG emissions from staple crops in China. Our results indicate that the average increment in the yield of three staple crops is 13.00% with SRF. Moreover, SRF decreased the N₂O emissions compared to those without straw returning in regions with 800–1200 mm of MAP, SOC > 20 g kg^–1, 0.9–1.5 g kg^–1 TN, pHs of 6.5–7.5, and a SRF duration < 3 years, in rice cultivation systems, and with partial SRF. However, irrespective of the climatic conditions, soil properties, or field management practices, SRF increased the CO₂ emissions compared to those without straw returning. Additionally, while SRF significantly increased the CH₄ emissions in paddy fields, it had no discernible effect on the CH₄ uptake in upland fields compared to that without straw returning. These findings offer valuable insights for optimizing straw management practices and reducing GHG emissions in farmland ecosystems.