Analysis of the Spatiotemporal Coupling Relationships and Influencing Factors between the Soil Organic Carbon Content and Crop Yield in Typical Farmlands in China

Abstract

Clarifying the relationship and reasons between soil organic carbon (SOC) and crop yield is a key task in achieving carbon neutrality goals and ensuring food security. However, due to the lack of analysis based on large-scale farmland monitoring data and research on deep soil, relevant research has not yet reached a consensus conclusion. Based on the monitoring data of 118 sample plots from 21 typical farmland and farmland compound ecosystem stations of China Ecosystem Research Network (CERN) between 2004 and 2020, the temporal and spatial coupling relationship between SOC content and crop yield in 0-20 cm and 0-100 cm soil layers and its influencing factors were determined. The results showed that between 2004 and 2020, SOC content in 0-20 cm soil layer, SOC content in 0-100 cm soil layer and crop yield in typical farmland in China showed a fluctuating upward trend. The coupling relationship between SOC content and crop yield was not always good in different periods, and there were great differences between different geographical divisions. Among the anthropogenic factors, exogenous carbon input can improve the coupling relationship between them by increasing soil organic carbon content and crop yield, while the effect of less and no tillage is limited. Among the natural factors, temperature, soil bulk density and farmland type all have an impact on farmland SOC content and crop yield at different significance levels. Different variables have different effects on SOC content and crop yield in typical farmland in different geographical regions. With the deepening of soil layer, the influence of anthropogenic factors such as exogenous carbon input on SOC content will decrease, but it still cannot be ignored. Based on the above conclusions, this study believes suggests that exogenous carbon input will play an important role in soil carbon sequestration and improving crop yield.

Keywords: soil organic carbon, crop yield, typical farmland, spatio-temporal coupling relationship, Exogenous carbon