An excerpt from the 2nd edition of Jon Stika’s A Soil Owner’s Manual, published by Acres U.S.A.
Many folks have attempted to understand why farmers have been reluctant to apply conservation practices to their land. I believe it is because farmers have been told that if they have soil erosion, they must build expensive structures to control it. This was a message without hope. Conservationists (myself included at the time) admitted that they could only help farmers slow the decline of their soil from the effects of erosion by attempting to catch the water and sediment as it tried to leave their field. This was not a very optimistic message and did not usually elicit positive responses from producers.
In contrast, educating producers about restoring soil health while reducing input costs is a message of hope. This is a message of restoration and true sustainability, and producers are responding positively and applying conservation practices as tools to pursue the goal of building soil health, rather than simply aiming to stem erosion. The primary obstacle to resolving the symptoms of water runoff and erosion is a lack of understanding of how the soil functions. Armed with this new understanding, we can now eliminate resource symptoms that are the result of dysfunctional soil.
Merriam-Webster’s dictionary defines “paradigm” as “a philosophical and theoretical framework of a scientific school or discipline within which theories, laws, and generalizations and the experiments performed in support of them are formulated; broadly: a philosophical or theoretical framework of any kind.”
Most people think of soil as “dirt.” In reality, soil is a living ecosystem that includes billions of organisms of untold species living in concert with each other and living plants. The soil paradigm shift that needs to occur is one of people changing the way they think about soil: from “dirt” to a “living ecosystem.” Soil is alive!
Producers need to ask themselves, “What functions do I expect my soil to perform?” When I ask farmers and others this question during workshops, I am typically met with blank stares. This is not because these folks are not intelligent or thoughtful. It is because no one has ever asked them that question before! Nevertheless, this fundamental question must be examined if any farmer, rancher, or gardener wants to be profitable and sustainable.
When asked what functions they expect their soil to perform, most people say, “To grow crops.” When asked what crops need in order to grow, they quickly answer, “Water, nutrients, sunlight, and air.” When asked if they know how soil must behave for good water infiltration, their answer typically includes the belief that tillage opens up the soil to allow water to infiltrate. In fact, tillage only briefly opens the soil while simultaneously reducing future infiltration capacity by destroying soil aggregates and the biologic glues that hold them together. This results in soil collapse and crusting with the next rain or application of irrigation water. The more the soil is disrupted with till- age in an effort to increase water infiltration, the more rapidly it will collapse and seal the next time it becomes wet.
When asked if they know how plant nutrients become available to plant roots, producers typically believe that fertilizer must be added to the soil, where the fertilizer dissolves in soil water and plants take in the nutrients. In fact, 90 percent of the nutrients taken up by plant roots are cycled through a soil organism before becoming plant available.
Virtually everything plants need is supplied by the soil organisms that live in collaboration with each living plant (Lavelle and Spain 2005, 112, 430-40). Less than a third of the nitrogen fertilizer applied to a field ends up in the plants grown there (Stevens et al. 2005). The rest is retained by some other form of life in the soil, volatilizes into the atmosphere, runs off the field, or leaches below the root zone with the movement of water.
Most analytic soil testing and fertilizer prescriptions are based on the response of crops grown in dysfunctional soils. Not surprisingly, the methods and prescriptions work quite well, for dysfunctional soils (Laboski et al. 2006).
This should come as no surprise: since most agricultural soils in the US do not cycle nutrients very well, testing methods and fertilizer prescriptions have evolved accordingly. This cycle of testing, prescribing, and applying an excessive amount of fertilizer to dysfunctional, unhealthy soil contributes to the soil remaining dysfunctional and declining even further (Mulvaney et al. 2009).
Water infiltration and nutrient cycling are just two basic examples of what we now understand are processes driven by the organisms living in the soil. This change in understanding how the soil works as a biological system is a major paradigm shift for almost everyone in agriculture. Armed with this new understanding of how the soil functions, producers can address the symptoms of erosion, runoff, nutrient leaching, drought, and poor crop performance to become truly sustainable.
The bottom line is that soil water becomes available to plants because soil microorganisms make the soil aggregates that allow the water to infiltrate and be stored in the soil. Soil microorganisms also cycle the vast majority of nutrients and make them available to plants.
If asked, most producers will tell you that they expect their soil to grow profitable crops by supplying water and nutrients. What many folks don’t realize is that these two basic expectations of soil function (water and nutrient supply) are biologically driven. Keep the soil microorganisms happy and the system runs at peak efficiency. A more efficient system will be a more profitable system.
