ASSESSING THE SOIL SYSTEM ; A REVIEW OFSOIL QUALITY LITERATURE

The soil quality discussion that has developed since the late 1980's has raised important issues about soil assessment and management. At the same time, it is often frustrating due to the lack of direct testing of the proposed concepts. The current discussion of soil quality is distinguished from previous soil assessment efforts by its attention to the dynamic soil characteristics that are affected by management choices. It is distinguished by focusing not just on characteristics such as nitrogen, phosphorous, potassium, and total organic matter levels, but also focuses on overall soil biological activity, organic matter fractions, water infiltration, and structural aggregation. In addition to crop production, the current soil quality discussion has considered soil functions such as management of water flow and the filtering and buffering of environmentally active substances. This discussion does not define soil quality only by the absence of degradation such as erosion, but by its fitness or ability to perform desired functions.