By Joseph Britt, Sand County Foundation
One of the lessons our project work at Sand County Foundation has taught us is about the complexity of the relationships among soil, water, nutrients, and the people who use these to feed the country.
Take the problem of excess phosphorus in Wisconsin. Much of our project work is directed at keeping phosphorus (also nitrogen) applied to agricultural land out of lakes and rivers. A major project in the upper reaches of the Milwaukee River, with Electric Power Research (EPRI), Milwaukee MSD, and local farmers, seeks to evaluate field-applied gypsum as a tool to reduce phosphorus runoff. Preliminary analysis of the data we’ve gathered, by our research partners at University of Wisconsin-Madison, suggests gypsum has great promise.
Gypsum, though, is not new in agriculture. It has been widely used for many years to make soils deficient in sulfur more productive. Adding gypsum also seems to increase the growth of organisms in the soil that can help sustain its productivity over time – but over-application can seriously damage some soils.
Sand County Foundation’s work with EPRI seeks to quantify gypsum’s value with relation to only one environmental outcome, reduced phosphorus runoff. One outcome of this in Wisconsin could be more widespread field application of gypsum as part of Adaptive Management Option projects to reduce phosphorus pollution, or water quality trades between farmers and downstream point sources like Milwaukee MSD.
However, our project work has taught us that quantifying environmental benefits has limits. The complexity of relationships in this part of the biological world make quantifying the total value of this and many other agricultural practices vastly more complex than what we’re attempting. It may, in fact, be too complex to be worth the effort it would require