Fertility Paradigms

Published Feb 11, 2001

In the last several years, you may have heard something about PFI’s work with fertility paradigms. If so, you probably heard the explanation that a paradigm is a way of looking at the world, a way of making sense of things. People have different ways of looking at soil fertility, for instance. One person asks, “Do I have enough soil fertility?” Another’s question is, “Do I have soil fertility in the right balance, or proportion?”

Soil scientists at land grant universities use the “do I have enough,” or “sufficiency” criterion, and they have calibrated crop responses with soil tests on this basis. The “balance” school of thought is represented by producers and consultants who view fertility in terms of the proportions of nutrients on the soil’s cation exchange; this could be termed the “ratio” approach. Little communication takes place between proponents of the sufficiency and ratio paradigms, and farmers are generally left on their own to decide where to put their money.

The PFI soil paradigms project was designed to spark discussion on this question and to discover what are the immediate outcomes producers could expect from adopting one approach or the other. This SARE-funded project was in its third and final year in 2001. Collaborators are Kathleen Delate, the ISU Organic Agriculture Specialist, Doug Karlen, a soil scientist at the National Soil Tilth Laboratory, and crop consultant Keith Cuvelier, of Supergrow of Iowa, Inc.

Results from 2001 come from six private farms and two ISU experiment farms. The cooperators were: Dennis and Eve Abbas, Hampton; John Bokelman, Ventura; John Hestad, Garner; Dave and Lisa Lubben, Monticello; Paul and Karen Mugge, Sutherland, and the New Melleray Abbey, near Dubuque. Cooperating ISU farms were the Armstrong Research Farm, near Atlantic, and the Bruner Research Farm, just west of Ames.