August 2003 white paper from IATP and IEC. Nonpoint source pollution (NPS) from agriculture is elusive in its definition and control. Many articles, laws, regulations, demonstration projects and targeted control approaches have in general failed to make a significant change in the agricultural practices most often identified with pollutant (nutrients, pesticides, bacteria, sediment) discharge to surface waters or of nitrate levels of ground waters in areas of intensive row crop and animal agriculture, and seldom have they been able to demonstrate measurable improvements in water quality.