Soil is a living system and soil fertility is the key to agricultural productivity. The maintenance of the fertility of the soil is the primary step in any agricultural system. The plethora of microorganisms inherent in any soil system ensures that the nutrient cycle is in place and the large substrate is broken down to minute particles that can be easily assimilated by the plant’s root system. Therefore, farmers should maintain the inherent soil fertility by replacing the nutrients removed by the crops or livestock grazing by using green manures, animal manures (raw or composted) and other natural fertilizers (e.g. rock phosphate).