The Effects of Tillage and Straw Incorporation on Soil Organic Carbon Status, Rice Crop Productivity, and Sustainability in the Rice-Wheat Cropping System of Eastern China

Soil management practices are used to enhance soil organic carbon, fertility, and crop productivity around the world. However, accurate information about the appropriate amount of straw incorporation is not available, because it is generally believed that at least 30% of the soil surface should be covered by straw, which is not implemented in all field environments. Therefore, a two-year (2016–2017) field experiment was conducted to investigate the impact of different percentages of straw incorporation and tillage methods, i.e., reduced tillage (RT) and conventional tillage (CT), on crop yield, soil organic carbon (SOC), total nitrogen (TN), and soil carbon storage (SCS) in rice–wheat cropping systems, under eight treatments. The experimental results showed that the greatest reduction in soil dry bulk density ( ρ b ) was found under CT with 100% straw coverage (9.79%), whereas the least reduction occurred under CT with no straw (1.31%). The mean TN concentration, soil organic matter (SOM), and soil carbon storage (SCS) were significantly higher by 0.98 g/kg, 17.07%, and 14.20%, respectively, under reduced tillage with 60% straw incorporation (RTsi60) compared with all other treatments. Our findings demonstrate that the incorporated wheat residues resulted in the highest rice production (7.95–8.63 t/ha) under RTsi60. We recommend the adoption of reduced tillage with 60% straw incorporation to increase rice yield, improve soil structure, and enhance TN, SOM, and SCS in paddy soil under rice-wheat rotation fields for agricultural sustainability.