Effect of land use on the characteristics of organic carbon and labile organic carbon in soil aggregates in Karst mountain areas

Abstract

Soil organic carbon is a dynamic medium of carbon transfer and is a main pathway for the circulation of carbon through soils in Karst systems. Karst systems are typically ecologically fragile areas with limited environmental capacity and resistivity. In addition, the implementation of a state policy encouraging the return of farmland to woodland (grass) and labor output in recent years has led to considerable change in land use patterns over a short period in these areas, which is bound to have far鄄reaching impacts on the spatial distribution pattern of soil organic carbon. Extensive previous research has investigated the response characteristics of soil organic carbon under different land use patterns. However in general, most of these studies have only investigated the total soil organic carbon in whole soils, and have rarely studied the organic carbon and labile organic carbon in soil aggregates. Organic carbon and labile organic carbon in aggregates are largely isolated from microbial activity because of the physical protection of the aggregates, and this may have a major impact on their function as soil carbon sinks. Therefore, the purpose of this study was to explore the distribution and accumulation characteristics of organic carbon and labile organic carbon in aggregates through survey, sampling, and analysis of soils in selected Karst

Impacts of abandoned sloping farmland on soil aggregates and aggregate-associated organic carbon in karst rocky desertification areas

“…These ndings highlight that SOC levels in 0-10 cm soil are mainly affected by increased SOC in 5-10 mm and 1-2 mm aggregates, while 10-20 cm soil is more in uenced by 2-5 mm aggregates. Li Juan et al (Juan Li et al 2013) found that the increase in total SOC in karst mountain areas depends on the increase in AAOC in the 1-5 mm aggregates. This study shows that AAOC in the 5-10 mm aggregates plays an important role in the accumulation of total SOC in the surface soil layer of 0-10 cm.…”