Overview & Objectives


Assessment of the potential for P delivery from agricultural land to surface waters is important in developing management plans for reducing P losses to surface waters.  The assessment should enable producers and other agribusiness professionals to identify high risk areas, diagnose major causes of P loss, and evaluate the effectiveness of alternative management practices.

This lesson addresses the assessment of potential for P delivery to surface waters resulting from the interaction of the source and transport factors addressed in Lessons II and III.  The basic concepts and applications of P indexes as risk assessment tools are explored.


Upon completing this lesson, a student should be able to:

1. Discuss the 'critical source area concept' relative to P delivery to surface waters.

2. Understand and be able to use two P indexes for risk assessment.

3. Determine the effects of different management practices on the estimated risk of P loss from agricultural land.

Copyright 2005

Development of this lesson was supported, in part, by a University of Nebraska Cooperative Extension grant. A contribution of the University of Nebraska Cooperative Extension, Journal Series 1074. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s).