Soluble Phosphorus Leaching from Corn Systems

Equilibrium-tension lysimeters were used to evaluate and compare dissolved reactive phosphorus (DRP) leaching from a prairie and fertilized no-tillage and chisel-plowed corn agroecosystems on Plano silt loam (fine-silty, mixed, superactive, mesic Typic Argiudolls) in south central Wisconsin during four monitoring periods, March through April 1996, 1997, and 1998, and from January 1999 through September 2000. A low level of soluble P was found to leach from both natural and managed ecosystems. Dissolved reactive P leaching losses were higher from the managed compared to the natural ecosystems. The fertilized notillage agroecosystem consistently maintained higher DRP concentrations in soil leachate solutions compared to the fertilized chisel-plowed agroecosystem, which led to higher DRP leaching losses for the fertilized no-tillage agroecosystem, despite greater drainage from the fertilized chisel-plowed compared to the fertilized no-tillage agroecosystem. Soluble P leaching losses measured for a prairie and fertilized agroecosystems in south central Wisconsin were below acceptable critical limits for P loss.