Nutrient and Sediment Loadings from a Subsurface Drainage System

ABSTRACT SEDIMENT, pesticide and nutrient losses were mea-sured from a 17 ha subsurface drainage system for the years 1976-78 using automatic sampling equipment. The monitored drainage system was installed in the early 1950's on a nearly flat Hoytville silty clay soil with limited surface runoff due to raised field borders. Dynamic responses of the drainage system are graphically presented and discussed as they relate to field manage-ment practices and climatic variations. A comparison was also made between this system with its low surface runoff and a more normal situation with partial subsur-face drainage and greater surface runoff. For the 17 ha system, runoff per unit area was substantially reduced resulting also in a similar reduction in sediment and nutrient losses.