Subsoiling reduces CO2 concentrations in soil profile of winter wheat - summer maize rotation ecosystem in the North China Plain: a strategy to achieve carbon neutrality in farmland

Reducing CO2 emissions from agricultural soils is a key component of the overall carbon reduction strategy. The closed chamber method was used to continuously monitor CO2 concentration in soil profiles of winter wheat-summer maize rotation fields in the North China Plain (NCP) during 2015-2017. Additionally, we evaluated the contribution of different tillage methods (Rotary tillage (RT), Subsoiling (SS), No- tillage (ZT), and conventional tillage (CT) in combination with Straw return (s) and straw removal (0)) to reducing soil CO2 emission. The results showed that the concentration of CO2 increased with the soil depth and peaked at the 150 cm layer. The trend of CO2 concentration in soil profiles under different tillage treatments was CTS > RTS > ZT(S) > SSS, and the average concentration in maize season was higher than that in wheat season. In addition, soil moisture and temperature in the 0-10 cm soil layer were significantly correlated with soil CO2 concentrations. Thus, our results highlight that the SSs plays a critical role in moderating soil CO2 emissions. This process merits further study to effectively regulate soil CO2 release and achieve carbon neutrality with less carbon emissions in farmland ecosystems.

Automated summary

Reducing CO2 emissions from agricultural soils is crucial for overall carbon reduction strategy. The study used the closed chamber method to monitor CO2 concentration in soil profiles of winter wheat-summer maize rotation fields in the North China Plain from 2015 to 2017. Different tillage methods were evaluated for their contribution to reducing soil CO2 emission. The results showed that CO2 concentration increased with soil depth, with the highest concentration at the 150 cm layer. Different tillage treatments had varying impacts on CO2 concentration, with subsoiling playing a critical role in moderating soil CO2 emissions. Soil moisture and temperature in the 0-10 cm layer were correlated with CO2 concentrations. Further research is needed to effectively regulate soil CO2 release and achieve carbon neutrality in farmland ecosystems.