Abstract

Studies have demonstrated some P loss reduction followingimplementation of remedial strategies at fi eld scales. However,there has been little coordinated evaluation of best managementpractices (BMPs) on a watershed scale to show where, when, andwhich work most eff ectively. Th us, it is still diffi cult to answerwith a degree of certainty, critical questions such as, how longbefore we see a response and where would we expect to observethe greatest or least response? In cases where fi eld and watershedscales are monitored, it is not uncommon for trends in P lossto be disconnected. We review case studies demonstratingthat potential causes of the disconnect varies, from competingsources of P at watershed scales that are not refl ected in fi eldmonitoring to an abundance of sinks at watershed scales thatbuff er fi eld sources. To be successful, P-based mitigationstrategies need to occur iteratively, involve stakeholder drivenprograms, and address the inherent complexity of all P sourceswithin watersheds.