Soil organic carbon loss following land use change in a semiarid environment

Abstract

Soil organic carbon is an essential part of soil and a valuable natural resource. Due to land use change SOC stocks are usually altered, which can seriously affect the environment and the ecosystem. The objective of this study was to investigate effects of different land use regimes (cropland, meadow and forest) and different soil types (Fluvisols, Chernozems, Vertisols and Solonetz) on SOC stocks. The results imply that soil type was the principal factor affecting SOC stocks. Topsoil SOC stocks (0-30 cm) decreased in the following order: Vertisols (93 t ha-1) > Chernozems (68 t ha-1) > Solonetz (65 t ha-1) > Fluvisols (48 t ha-1). The conversion of native ecosystems (forests and meadows) to croplands induced a significant SOC stock decrease and a considerable degradation of soil. Forests contain 72 t ha-1 of SOC, meadows 71 t ha-1 and cropland 62 t ha-1. The highest historical loss of SOC stock due to the conversion of native ecosystems was obtained in Chernozems (16-18%), Vertisols (15- 17%) and Fluvisols (13-22%), while such a loss in Solonetz was negligible (1-3%). Determining historical SOC loss based on different soil types provides useful information on potential soil degradation and sequestration potential and might thus be used as a guideline for soil protection.