Assessing the effects of agricultural management practices and land-use changes on soil organic carbon stocks

Soil organic carbon (SOC) stocks have profound effects on climate change, sustainable agricultural development, and environmental management. Our objectives were to propose a conceptual framework and quantify the impact of land use change (LUC) and agricultural management practices (AMPs) on SOC stocks. By comparison, we choose the Kriging-based spatial prediction model to estimate SOC stocks based on the field sampled soil data (depth of 0-30 cm) in 2005 and 2019. Film mulching, drip irrigation, and fertilizer application were selected to represent the regional AMPs. Our results indicate that SOC stocks increased by 12.7% in the Sangong river basin from 2005 to 2019. From the proposed conceptual framework, we notice that the transition between different land-use types may cause both losses (e.g.,-9.49 Gg C caused by expansion of construction land) and gains (e.g., +3 Gg C caused by the conversion of cultivated land to grassland) of SOC storage. Benefiting from improved AMPs (e.g., film mulching, drip irrigation, and fertilizer application), the stable cultivated land category contributes the most (+36.0 Gg C) to the growth of SOC stocks.

Automated summary

Soil organic carbon (SOC) stocks have significant impacts on climate change, sustainable agricultural development, and environmental management. This study aimed to propose a conceptual framework and quantify the influence of land use change (LUC) and agricultural management practices (AMPs) on SOC stocks. Using a Kriging-based spatial prediction model, SOC stocks were estimated based on field sampled soil data (0-30 cm depth) in 2005 and 2019. Film mulching, drip irrigation, and fertilizer application were chosen as representative AMPs for the region. Results show that SOC stocks increased by 12.7% in the Sangong river basin from 2005 to 2019. The proposed conceptual framework reveals that transitions between land-use types may cause both losses (e.g., -9.49 Gg C from expansion of construction land) and gains (e.g., +3 Gg C from conversion of cultivated land to grassland) in SOC storage. Improved AMPs, such as film mulching, drip irrigation, and fertilizer application, contribute the most (+36.0 Gg C) to the growth of SOC stocks in the stable cultivated land category.