For nutrient management organic farmers mostly relies on the natural breakdown of available organic matter, using various techniques i.e. green manuring; vermi-composting and composting to replace nutrients taken from the soil by previous crops. Organic farming uses a variety of methods to improve soil fertility, including crop rotation, cover cropping, reduced tillage, and application of compost. By reducing tillage, soil is not inverted and exposed to air; less carbon is lost to the atmosphere resulting in more soil organic carbon. This has an added benefit of carbon sequestration, which can reduce greenhouse gases and help reverse climate change.
Organic farmers use cover crops; crop rotation; crop residue and animal manure, certain processed fertilizers such as de-oiled cakes ; bone meal; biofertilisers and various mineral powders such as rock phosphate and green sand, a naturally occurring form of potash that provides potassium. In some cases pH may need to be amended, therefore, natural pH amendments include lime and sulfur.
Biological research soil and soil organisms has proven beneficial to organic farming. Varieties of bacteria and fungi break down chemicals, plant matter and animal waste into productive soil nutrients. In turn, they produce benefits of healthier yields and more productive soil for future crops. Fields with less or no manure display significantly lower yields, due to decreased soil microbe community. Increased manure improves biological activity, providing a healthier, more arable soil system and higher yields.