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Soil Processes
and Properties
Temperature changes will have only minimal effects on reaction
rates for inorganic processes in soils, but changes in soil moisture could
have significant effects on rates of diffusion and supply of nutrients to
plants.
Carbon Dynamics
The global pool of carbon is available for cycling by natural processes on interannual to centery timescales (i.e., all except fossil carbon) in reservoirs as follows:
Soil | 1500 Gt |
Aboveground biomass | 600-700 Gt |
Atmosphere | 800 Gt |
Ocean | 40,000 Gt |
Land use is a much more important factor than changes in NPP for determining soil carbon. Typically about half of the native carbon is lost from soils when they are put under cultivation over a period of 50-100 years. Minimum tillage practices reduce carbon loss from soils.
Soil Biodiversity
Climate change, specifically changes in temperature and water availability, could change soil microbial and faunal populations, but changes in land-use practices are likely to have much greater impact. However, another element of global change, namely increased deposition of nitrogen from industrial NOX emissions, is being more widely associated with major losses of fungi in the root zone in some (particularly forest) biomes.
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