Carbon sequestration efficiency in red paddy soil originating from different parent materials in Jiangxi, China

Abstract

Red paddy soils in southern China originate from various parent materials; however, the respective characteristics of C sequestration efficiency (CSE) are unclear. Here, three cultivated land monitoring sites in Jiangxi province were examined, with soils originating from argillaceous rock, quaternary red clay, and granite. We assessed crop yield and soil physicochemical properties over several years and measured soil organic C (SOC) storage, SOC fractions, and chemical structure in 2019 to test differences in CSE characteristics, SOC structure stability, and factors affecting red paddy soils. The change in SOC storage under long-term fertilization showed the following descending order: red paddy soils derived from argillaceous rock (1.10 t ha−1 yr−1) > granite (0.75 t ha−1 yr−1) > quaternary red clay (0.12 t ha−1 yr−1); the order of CSE was granite (0.24) > argillaceous rock (0.22) > quaternary red clay (0.08). Red paddy soil from argillaceous rock had the highest proportion of recalcitrant organic C (ROC) and SOC stability (aromaticity 0.45). Red paddy soil originating from granite had the lowest ROC proportion (54%) and SOC stability (aromaticity 0.35). Soil properties, organic C input, and amount of N fertilizer explained 53.6% of the total CSE variation. SOC, pH, and organic C input were the main factors affecting CSE, with relative contribution rates of 36.4, 6.2, and 6.3%, respectively. pH (30.4%) was the main factor affecting CSE variation in argillaceous rock paddy soil. Soil organic C (52.2%) was the main factor explain CSE variation in quaternary red clay-derived red paddy soil. Soil organic C and organic C input explained 39.4 and 21.3% of the variation in CSE in granite-derived paddy soils. The parent material can directly or indirectly affect CSE through soil texture.