Soil is a unique habitat which harbours a variety of microflora and fauna, and gives mechanical and nutritional support to higher plants on which human civilization is based. Structural components of soil and its major constituents determine soil quality.
Soil is as important as water and air. Human life could not be sustained with access to soil, because it is the source of most of our food. The economic well-being of most of the nations on earth depends greatly on arable soils and the ways of maintenance of their productivity.
Moreover, a good quality soil also acts as an environmental filter for cleaning air and water. Soil is the ultimate receptors and reservoir of nutrients released from organic matter. It also sends the nutrients back to plants.
Soil quality can be defined as the capacity of a soil to function within the boundaries of ecosystem to sustain biological productivity, maintain environmental quality and promote plant and animal health.
Soil quality encompasses its capacity for:
(i) Crop productivity,
(ii) Food safety, and
(iii) Health of animals and humans.
Soil quality can improve or deteriorate depending on the influencing factors. The factors that cannot be affected are; geology, topography, climate and time (Fig. 30.1). The factors which can be influenced are humus content, phosphorus status, degree of saturation, etc.
