AnnAGNPS Pollutant Loading Model
O. Soil Composite
The soil profile used is a two-layer system based upon the multi-layer input data. The top layer is considered a tillage layer of constant thickness (20 cm) unless bedrock is within 20 cm of the surface. Certain properties of the top layer may vary due to tillage operations such as bulk density. The second layer has static properties and does not exceed a 2-meter depth from the surface.
Fred D. Theurer