Phosphorus soil testing: Innovations for water quality protection

Modem agricultural management practices for phosphorus (P), including soil testing, can no longer focus exclusively on soil fertility and agricultural productivity but must also address the role of agricultural P in nonpoint source pollution of surface waters. The eutrophication of streams, rivers, lakes, and bays as a result of P loss from soil to water points to the need for advances in soil testing that can contribute to water quality protection. A concerted research effort to modify, refine, and advance soil testing for P to achieve environmental as well as agronomic objectives has been underway for the past decade; unfortunately, little of this research has been adopted by soil testing programs in the United States. The intent of this paper is two-fold. First, to briefly review some of this research, illustrating its potential value in soil P management programs that, by necessity, must today have both agronomic and environmental components. And second, to provide recommendations as to how soil testing laboratories can be more proactive at integrating advances in research on the environmental uses of soil P testing into their programs and, by doing so, in re-shaping their roles in sustaining a productive, environmentally sound agriculture.