ABSTRACT
Organic farming is a production system that sustains agricultural production by avoiding or largely excluding synthetic fertilizers and pesticides. External resources, such as commercially purchased chemicals and fuels, are replaced by resources found on or near the farm. The internal resources include solar or wind energy, biological pest controls, and biologically fixed nitrogen and nutrients released from organic matter or from soil reserves. The most important difference between organic farming and conventional agriculture is that organic farmers avoid or restrict the use of chemical fertilizers and pesticides in their farming operations, while conventional farmers may use them extensively. Most organic cropping systems include a legume-based rotation with green manure or cover crops. The key to maintaining soil fertility in an organic system is the increased efficiency of nutrient flow from the fixed to the soluble state.
