Performance-based Nutrient Management Evaluation

Chad Ingels, P&S, ISUE Performance-based Watershed Project, Northeast

Problem Statement:

The Hewitt-Hickory Creek watershed in northwest Dubuque County has been named on the IDNR impaired waters list. The water quality issues have been attributed to concentrated livestock production and agricultural land use. The farmers in the watershed want to do not want regulations forced on them that would inhibit their farms profitability.

Programmatic Response:

A watershed council was formed to voluntarily address water quality issues in the watershed.  A major component of the councils work involves promoting the use of performances measures, such as the Iowa Phosphorus Index, Soil Conditioning Index and end-of-season cornstalk nitrate-nitrogen test, to evaluate environmental impacts by field, farm and watershed.


Thirty-eight farmers in the watershed decided to become involved in the watershed effort and provide their individual field information so that the Iowa P Index and Soil Conditioning Index could be calculated.  Through the information gathering process each farmer completed a simple, one page, form identifying their crop rotations, tillage practices and nutrient applications.  The farmers also provided field-specific soil test information needed to calculate the P Index.

Individual farm reports were prepared for each operation and a cumulative summary of all fields was also provided to each participant.  Significant levels of learning occurred during the information gathering and reporting processes.  The farmers learned about the several components that go into each index and what impacts their current practices have on the outcomes.  The primary learning outcome was that the farmers took time to look at their soil tests by field.  Many times the ag supplier manages these numbers and the farmers do not take time to review their soil resource potentials.

Other outcomes from evaluating their P Index and Soil Conditioning Index values were changes in manure management strategies, primarily which fields would be targeted for manure applications; installation of waterways and a better understanding of their impact on reducing sediment delivery to nearby water sources; a renewed emphasis on the importance of longer, multiple crop rotations; and becoming more open to changing or reducing tillage operations.

For the first time, the farmers of the Hewitt-Hickory Creek watershed came together and discussed ways to reduce the risk of phosphorus and soil from leaving their farms and their watershed.  Utilizing summaries of all the participating fields each farmer knows exactly which of his fields needs improvement and how he might go about making those improvements and what the resulting outcome might be for his farm.

September 2006

103 - Nutrient Management

Page last updated: October 19, 2006
Page maintained by Linda Schultz,