The response of crop yield, carbon sequestration, and global warming potential to straw and biochar applications: A meta-analysis.

Organic materials play an important role in improving crop yield. However, due to variations in natural and field management practices, the impact of straw incorporation (NS) and biochar addition (NB) on soil organic carbon (SOC) sequestration and global warming potential (GWP) remains uncertain. This meta-analysis synthesizes the findings from 112 published studies, encompassing 897 samples, to assess the effects of NS and NB on crop yield, SOC, and GWP. The results reveal that Northeast China has the highest SOC stocks (40.80 Mg ha) and annual SOC sequestration (4.27 Mg ha yr) compared to other regions. Notably, the NS and NB differ in their effect sizes on improving crop yield (7.68 % and 8.23 %, respectively) and SOC (6.92 % and 30.72 %, respectively), with opposing effects on GWP (increasing by 37.69 % in NS and decreasing by 23.94 % in NB). Following organic material application, climatic conditions, crop and field type, and soil properties affected SOC content and GWP. The main factors influencing variations in crop yield, SOC, and GWP were mean annual temperature and precipitation, initial SOC content, and soil pH, accounting for 57.46 %-60.29 %, 54.75 %-58.52 %, and 61.81 %-65.11 %, respectively. Considering the need to balance food demand, soil fertility and environmental benefits, biochar emerges as a recommended strategy for advancing future agriculture goals. In summary, this study quantitatively assessed the impact of organic material on crop yield, SOC, and greenhouse gas emissions, offering a scientific foundation for optimizing these factors under diverse regional conditions.