The definition of soil health is changing. For many decades, the study of soil health emphasized soil’s physical and chemical properties. Today, soil scientists strive to include biological aspects as well, since many of the processes that influence soil occur because of living organisms. These four strategies are based on four basic soil health principles outlined by the USDA Natural Resources Conservation Service (NRCS): 1. Minimize soil disturbance 2. Keep soil covered 3. Maximize plant diversity 4. Maximize the period of living root growth.