Effect of land use conversion on soil organic carbon sequestration in the loess hilly area, loess plateau of China

Abstract

Changes in land use may alter land cover, which results in carbon stock changes in biomass as well as in the soil. In China's loess plateau, vegetation restoration has been conducted since 1950s to control soil erosion and improve the ecosystem, with significant investment of money and manpower. Despite these efforts, soil erosion has still been severe. To reduce soil erosion and improve land quality, China initiated another state-funded project, Grain-for-Green, in 1999 in the loess plateau. However, it is not clear how effective this newly initiated project will be. In this study, we evaluated the effect of land-use conversion on soil organic carbon (SOC) and the potential effect of the current project on SOC sequestration in the Anjiapo catchment area of the loess hilly area of the loess plateau in China. This evaluation is based on SOC measurements in cropland versus in other converted land use types. We found that SOC sequestration mainly occurred in the surface soil after land use conversion took place. Land use conversion from cropland to shrubland or wild grassland (i.e. undisturbed land) was better for SOC sequestration than tree plantation in the semi-arid loess hilly area. By using the land use change in the study area as a scenario, the potential contribution of land use change on SOC sequestration due to the Grain-for-Green projectwas estimated. It was found that this project in the loess plateau of China would be helpful for SOC sequestration ifsuccessfully implemented.

Erosion-induced massive organic carbon burial and carbon emission in the Yellow River basin, China

“…Calcaric Regosols, grey Podzolic soils, and Calcisols are the dominant soil orders, which together cover ∼ 70 % of the total surface area. The SOC in the loess soils is very low, and the SOC pool has been recently increased as a result of continuous vegetation rehabilitation (Chen et al, 2007).…”

“…Due to widespread implementation, at least 70 % of the soils stabilized by slope control measures are attributable to the restored vegetation. The soils stabilized by vegetation were assumed to have the same OC content as the noneroded topsoils (Chen et al, 2007). For the built terraces, crop planting, mainly potato, wheat, and maize, is pursued periodically.…”

Effects of vegetation restoration on soil organic carbon sequestration at multiple scales in semi-arid Loess Plateau, China

“…In 1999, another project, Grain-to-Green, was initiated for soil erosion control and land quality improvement using widespread conversion of sloping cropland to forest and grassland on the Loess Plateau. In this project, it was suggested to convert all croplands with slopes of over 25°to green land covered with forest or grass, while the local farmers would receive grain and cash subsidy from the government for the loss of food due to cropland decrease (Chen et al, 2007).…”

Ecosystem Services and Ecological Restoration in the Northern Shaanxi Loess Plateau, China, in Relation to Climate Fluctuation and Investments in Natural Capital

“…At the same time, the grasslands increased by only 0.13%, because many grasslands were converted into woodlands. Dramatic changes in land use in the NSLP caused a series of ecological effects [2,32,33]. (Table 1), it can be seen that 694 km 2 and 556 km 2 of croplands in 2000 have been replaced by woodlands (including scrublands) and grasslands, respectively, due to the GFG project.…”