Modeling Carbon Dynamics in Paddy Soils in Jiangsu Province of China with Soil Databases Differing in Spatial Resolution

A number of process-based models have been developed for quantifying carbon (C) sequestration in agro-ecosystems. The DeNitrification-DeComposition (DNDC) model was used to simulate and quantify long-term (1980–2008) soil organic carbon (SOC) dynamics in the important rice-producing province, Jiangsu, China. Changes in SOC storages were estimated from two soil databases differing in spatial resolution: a county database consisting of 68 polygons and a soil patch-based database of 701 polygons for all 3.7 Mha of rice fields in Jiangsu. The simulated SOC storage with the coarse resolution county database ranged between 131.0–320.6 Tg C in 1980 and 170.3–305.1 Tg C in 2008, respectively, while that estimated with the fine resolution database was 201.6 and 216.2 Tg C in 1980 and 2008, respectively. The results modeled with the soil databases differing in spatial resolution indicated that using the soil input data with higher resolution substantially increased the accuracy of the modeled results; and when lacking detailed soil datasets, the DNDC model, parameterized with the most sensitive factor (MSF) method to cope with attribute uncertainty, could still produce acceptable results although with deviations of up to 60% for the case study reported in this paper.