Increasing soil organic carbon sequestration and yield stability by no‐tillage and straw‐returning in wheat–maize rotation

Knowledge about the changes in soil organic carbon (SOC) stocks and grain yields under different field management practices is necessary for achieving agricultural sustainability. An 8‐yr experiment for testing different tillage and straw management practices was conducted in a wheat ( Triticum aestivum L.)–maize ( Zea mays L.) rotation system in the southern Loess Plateau of China. Three tillage methods (control with no‐tillage and straw removal [CK], no‐tillage with straw stubbles 30–40 cm in height [NT], and rotary tillage with straw incorporation [RT]) were applied before maize planting, and two straw treatments (straw return [SR] and no straw return [SR0]) were applied after maize harvest. Over the 8 yr, SOC stocks exhibited similar dynamic changing trends in all treatments but were higher under NT, RT, and SR than under CK‐SR0. Compared with the initial soil, SOC stock increased the most (34.1%) in NT‐SR. Compared with the CK‐SR0, the NT‐SR, RT‐SR, CK‐SR, NT‐SR0, and RT‐SR0 increased wheat grain yields by 47.2, 36.8, 24.9, 25.1, and 20.0%, respectively. Similar trends were found for maize grain yields. The NT, RT, and SR increased crop yield stability with the highest sustainable yield index in NT‐SR for both wheat (.67) and maize (.70). Overall, the combination of no‐tillage with wheat straw stubbles 30–40 cm in height and maize straw return was the best strategy for improving SOC stocks, grain yields, and agricultural sustainability for grain production in dry, sub‐humid areas of northwestern China.