Innovative management of agricultural phosphorus to protect soil and waterresources

Agriculture, particularly livestock agriculture, is receiving increasing pu blic scrutiny due to non-point source phosphorus (P) pollution and eutrophi cation. Much of today's situation may be attributed to system level trends in specialization and intensification that result in excess P entering live stock farms. Balancing P at the farm gate represents a necessary step for l ong-term soil and water quality protection. Remedial P management combines source and transport control that confront critical areas of P export in su rface and subsurface runoff from agricultural landscapes. Source management seeks to immobilize P in the environment through such strategies as reduci ng soluble P in manure, targeting P application to soils with high retentio n capacities, and managing soil P. Transport controls employ an understandi ng of loss or transfer mechanisms to avoid P application on areas with a hi gh transport potential. Also, the potential for P transport can be reduced by implementation of conservation practices such as reduced tillage, terrac ing, and stream buffers. However, implementation of agricultural management strategies that minimize P export must consider the cost effectiveness of alternative measures, as low practice adoption may limit or impede water qu ality benefits.