SOIL FERTILITY

The focus of the farming system recommended by ERA Farming is on soil fertility as we consider that a fertile, healthy soil produces healthy plants, naturally and sustainably.The fertility of a soil is related to its sustained capacity to produce valuable output with minimal input. Soil fertility is dependant on the physical, chemical and biological characteristics of the soil. A healthy, balanced soil is composed of approximately 45% minerals, 25% water, 25% air and 1-5% organic matter and living organisms (Zimmer, 2000). When soil fertility is defined in terms of the value of commercial production, the focus often centres on the physical and chemical components of the soil. This is because the biological component of soil fertility is easily overridden by addition of chemical fertilisers. In contrast, when sustainability of the soil resource is emphasised, the biological components of the soil are of greater importance.