The nature of fertility degradation includes soil organic matter loss, which leads to the depletion of organic C, N, organic P and organic S. Losses of organic C following land use change from native vegetation (forests, woodlands, grasslands) to cropping vary from 20 % to 80 %, and besides soil fertility degradation, has contributed almost 120 x 1015 g of CO2-C to the atmosphere over the last 12,000 years. Since N, organic P and organic S are closely linked, loss of SOM also leads to the depletion of N, P and S. In addition, SOM loss also leads to the depletion of energy source to microorganisms hence microbial biomass loss, loss of cation exchange capacity in low activity clay soils and coarse-textured soils, reduced pH buffer capacity, reduction in complexed micronutrients, and increased aggregate breakdown due to reduced supply of aggregate forming and stabilising organic agents.