ABSTRACT
Terrestrial ecosystems, comprising world biota and soils, play a major role in regulating atmospheric concentrations of radiatively-active gases. Soil is a principal medium for plant growth, and about 99% of the human food supply comes from soil and related ecosystems. In developing economies, soil degradation leads to deforestation and expansion of agricultural activities to marginal lands in ecologically-sensitive ecoregions. Deforestation and cultivation of grasslands are among the major causes of greenhouse gas emissions. The magnitude and type of greenhouse gas emissions from soil degradative processes depend on land use, cropping systems, and soil management. Soil management affects carbon dynamics and gaseous emissions through its influence on soil properties and processes. Principal soil properties affected by soil management are soil moisture and temperature regimes, aeration, and aggregation. Soil tillage is an important tool to regulate decomposition constant k. While plow-based tillage may increase k, conservation tillage systems decrease k.
