protected to serve as sinks for sediments, nutrients, and pesticides, to protect the stream bank from erosion, and to reduce excessive runoff into stream channels. Loss of these areas will increase existing water quality problems or create new ones. The cost of replacing the water quality benefits of existing vegetation with efforts on the farm level to increase soil quality, input use efficiency, and resistance to erosion may be high.

The creation of field or landscape buffer zones should augment efforts to improve farming systems. They should not be substitutes for such efforts.

The creation of field or landscape buffer zones cannot be seen as an alternative to efforts to improve farming systems. The capacities of field and landscape buffer zones to trap and immobilize sediments, nutrients, and pesticides are limited by the size of the buffers, the plants growing in the buffers, and the manner in which the buffers are managed. Both field and landscape buffer zones can be overwhelmed by large flows of runoff water, sediment, nutrients, and pesticides. Efforts to improve farming systems and to create field or landscape buffer zones are complementary. Emphasis on one effort to the exclusion of the other will achieve much less improvement in soil and water quality than is possible by striking a balance between the two efforts.