How can straw incorporation management impact on soil carbon storage? A meta-analysis

Straw incorporation (SI) is a common practice in China and has important implications for agricultural sustainability. This study aimed to quantitatively summarise the response of top soil (0–20 cm) carbon (C) to SI under different agricultural management regimes. Results indicated that compared with straw removal (SR), SI significantly increased soil C storage by 12 %. Moreover, incorporation of chopped straw with tillage treatment (ploughing and rotary tillage) increased C storage compared to unchopped straw without tillage treatment. SI implementation with upland cropping, in the northwest and northeast resulted in higher C storage compared with rice cropping, and in the northern and southern regions. Changes in soil C were observed based on SI variables, including tillage and straw amounts in fine-textured soils, however straw amount rather than tillage treatment exhibited a greater influence on soil C in coarse-textured soils. We concluded SI implementation with increased amounts of chopped straw for a longer duration was favourable to soil C sequestration in Chinese croplands. Furthermore, we estimated if SI was popularised across all of China’s agricultural regions, soil C sequestration potential would reach 48.2 ~ 56.2 Tg C year−1. SI practices should therefore be encouraged.