Nutrients from organic sources also can become pollutants when misapplied or over-applied. Keeping the ground covered Bare soil is susceptible to wind and water erosion, and to drying and crusting. Farmers often leave crop residue on the surface to cover the ground between growing seasons. Living cover crops create new organic matter and help feed soil organisms. Groundcover must be managed to prevent problems with delayed soil warming in spring, diseases, and excessive build-up of phosphorus at the surface.
Diversity is beneficial for several reasons.
Each crop contributes a unique root structure and type of residue to the soil. A diversity of soil organisms helps control pest populations, and a diversity of cultural practices reduces weed and disease pressures. Diversity across the landscape can be increased by using buffer strips, small fields, or contour strip cropping. Diversity over time can be increased by adding crops to the crop rotation or by varying tillage practices. Changing vegetation across the landscape or over time not only increases plant diversity, but also the types of insects, microorganisms, and wildlife that live on your farm.