PHOSPHORUS LEACHING AND POTENTIAL LOSS WITH ARTIFICIALSUBSURFACE DRAINAGE

摘要

Phosphorus (P) movement from the field to a surface water resource can occur with surface runoffwater, with sediment transported in that runoff water, and with subsurface drainage. Because of increased concernsfor P contamination of fresh waters, especially related to manure management, several states have or are developinga P-index as a management tool to reduce P movement. An important part of such an index for soils that areartificially drained is the correct assessment of the relative importance of soluble P transported with subsurfacedrainage in determining total P loss from a field. Data from column studies illustrate the degree to which soluble Pcan move vertically through a soil profile. However, once the P-laden percolating water reaches the water table, onecould hypothesize that subsequent lateral movement of that water through low-P subsoils would then reduce Pconcentrations. Data from field studies on the water quality of artificial subsurface drainage and from a speciallydesigned field experiment support this hypothesis.