Soil carbon is the largest terrestrial pool of carbon and plays a key role in the global carbon cycle. Soil organic carbon is also a key determinant of soil quality, affecting cation exchange capacity, supply of nutrients to plants, water holding capacity and soil physical structure. Soil carbon is also the principle energy source for microbes and sustains soil biodiversity. Soil organic nitrogen and soil organic sulphur are the predominant pools of nitrogen and sulphur in soils and their mineralization is the main supply of nitrogen and sulphur respectively for plant growth and development. Soil inorganic carbon accounts for about one third of the total carbon in soils globally and has considerable influence on the physical and chemical properties of soil.
