Distribution characteristics of soil organic carbon under the influence of parent material and soil type

Soil organic carbon is an important component of the terrestrial ecosystem carbon pool, playing an important role in the carbon cycling process of farmland soil and the quality of farmland. The spatial distribution characteristics of soil organic carbon are affected by many factors, among which parent material and soil type directly affect the distribution of soil organic carbon. The authors in this study took Yanji Jiuchao Plain in the central eastern region of Yanbian Prefecture in Jilin Province as an example to analyze and study the distribution characteristics and influencing factors of soil organic carbon in typical soil profiles in the area through systematic stratified sampling. The results showed that the average organic carbon content in the soil of Jiuchao Plain in Yanji was 48.68×10^-3, which was generally rich. And the organic carbon content gradually decreased with the increase of profile depth in vertical direction. Besides, the content of the surface organic carbon(0, 20 cm) was significantly higher than that of the deep soil, showing surface aggregation. The main types of parent material in Jiuchao Plain of Yanji were Mesozoic sandstone weathering materials and Quaternary loose deposits. The soil organic carbon enrichment ability developed by Quaternary loose deposits was lower than that developed by Mesozoic sandstone weathering products, with higher loss rate and variability. The main soil type developed in Yanji Jiuchao Plain was dark brown soil and paddy soil. The organic carbon content of soil with different types had a significant negative relationship with the soil depth. Compared with dark brown soil in the same soil layer, paddy soil had high variability and significant loss along the depth profile. The research results could provide basic data for evaluating the carbon sources and sinks of soil organic carbon in Yanji Jiuchao Plain, and could provide references for the spatial distribution of soil organic carbon and changes in deep soil organic carbon in Northeast China.