Acknowledgements
We gratefully acknowledge financial support for this research from the
National Key R&D Program (2016YFD0200308), and the Key R&D Program of
Shaanxi (2019ZDLNY01-05-01), the Key Technologies R&D Program of China
during the 12th Five-Year Plan period (2012BAD14B11).
Abstract
Knowledge about the changes in soil organic carbon (SOC) stocks and
grain yields under different tillage and straw management is necessary
to assess the feasibility and sustainability of conservation
agriculture. An 8-year experiment was conducted in an intensive 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. Thus, the treatments included CK-SR,
CK-SR0, NT-SR, NT-SR0, RT-SR, and RT-SR0. Over 8 years, the SOC stock
exhibited similar dynamic trends in all treatments, but was higher in
NT, RT, and SR plots than in CK-SR0 plots. Compared with the initial
soil, the SOC stock increased largest (34.1%) in NT-SR. Compared with
the CK-SR0, the NT-SR, RT-SR, CK-SR, NT-SR0 and RT-SR0 increased the
wheat grain yield by 47.2%, 36.8%, 24.9%, 25.1%, and 20.0%,
respectively. The NT, RT and SR increased crop yield stability with the
highest sustainable yield index in NT-SR for both wheat (0.67) and maize
(0.70). This study showed the NT-SR was the best strategy for improving
SOC stocks, grain yields and agricultural sustainability for the
wheat-maize rotation system in northwestern China and other areas with
similar climates and cropping systems.