Brinkman and Sombroek (1996) give an overview of changes in soils in food-producing regions that likely will occur under global environmental change. Changes in soil-forming factors directly resulting from global change would be organic matter amount from biomass, soil temperature, and soil hydrology. It is important to recognize that these changes could improve plant nutrient status in soil and lead to increased annual production of biomass or crops.
Direct global climate changes that likely will impact soils include generally higher temperature, particularly at high latitudes, and a more intense hydrological cycle with locally higher precipitation and generally higher evapotranspiration. Indirect effects of climate change resulting from enhanced CO2 include increased rate of plant growth and increased water-use efficiency.
Increased plant productivity will be accompanied by more litter or crop residue, more root growth and soil microbial activity, and more nitrogen fixation in the root zone. Greater soil microbial activity increases the rate of plant nutrient cycling in the soil, increasing root material and raising soil organic matter. Higher ratios of carbon to nitrogen in plant residue would slow decomposition and provide more time for incorporation into the soil by earthworms and termites, which, in turn, enhances soil infiltration and suppresses soil erosion and nutrient run off.
Reference
Brinkman, Robert, and Wim G. Sombroek, 1996: The effects of global change on soil conditions in relation to plant growth and food production. In F. Bazzaz and W. Sombroek, eds., Global Change and Agricultural Production. Food and Agricultural Organization of the United Nations and John Wiley & Sons, New York, 345 pp.