Recent Trends in Soil Degradation Research in Drylands: Soil Organic Carbon, Temperature and Water as Affected by Land Use and Climate Change

Abstract

This review focuses on the effect of soil degradation due to land use on climatic variables (soil temperature and water), the effect of climatic variables on soil organic matter (SOM) decomposition rate in drylands, and the effects of soil degradation and concurrent climate change on soil organic carbon (SOC) accumulation. There is contradictory evidence about the effect of soil degradation on soil temperature and water, and the effect of soil temperature and water on SOC accumulation. From a general viewpoint, soil degradation and drought increase soil temperature and decrease soil water, both of which result in decreased SOC accumulation. On the other hand, from the viewpoint of recent results from drylands, water deficits decrease the decomposition rate of SOM, consequently causing increased SOC accumulation in drylands. However, decreases in aboveground net primary production (NPP) due to land degradation may accelerate wind erosion and fertile soil loss. Therefore, the extent of soil degradation and concurrent climate change would be deeply related to the above-ground NPP in drylands.