Soil fertility refers to the ability of soil to sustain agricultural plant growth, i.e to provide plant habitat and result in sustained and consistent yields of high quality. A fertile soil has the following properties:

•  The ability to supply essential plant nutrients and water in adequate amounts and proportions for plant growth and reproduction; and

• The absence of toxic substances which may inhibit plant growth.The following properties contribute to soil fertility in most situations:
  

• Sufficient soil depth for adequate root growth and water retention;

• Good internal drainage, allowing sufficient aeration for optimal root growth (although some plants, such as rice, tolerate waterlogging);

• Topsoil or horizon O is with sufficient soil organic matter for healthy soil structure and soil moisture retention;

• Soil pH in the range 5.5 to 7.0 (suitable for most plants but some prefer or tolerate more acid or alkaline conditions);

• Adequate concentrations of essential plant nutrients in plant-available forms;

• Presence of a range of microorganisms that support plant growth.