Soil organic carbon dynamics in intensively managed agricultural landscapes of eastern China

Quantifying soil organic carbon (SOC) dynamics is critical for monitoring agricultural sustainability and mitigating global climate change. A study was done to investigate the SOC changes between 2003 and 2016 by DeNitrification-DeComposition (DNDC) model in an intensively cultivated region of eastern China, using a detailed high-resolution soil database, which contained 4875 sites (0–20 cm depth) with the sampling density of one sample per km² in 2003. Results showed the DNDC model had good performance for simulating the SOC dynamics in the study area. Spatial analysis showed that 71% of the study area gained C, whilst 29% maintained their C balance with no C loss in all areas. Results suggested that the current management practice facilitated soil C sequestration in this region although soil type also played an important role. SOC density (SOCD) in lime concretion black soil was significantly higher than those in other soils. The averaged global warming potential ranged from 3865.8 to 7110.8 kg CO₂ equivalent ha⁻¹ yr⁻¹ from 2003 to 2016 with CH₄ contributing the largest proportion, which might be associated with the high input of fertilizer. Spatially high-resolution estimates of SOC using DNDC can support dual agricultural and carbon management in this region.