Monday, April 15, 2013

(Mis)Conceptions about Soil Health

By Logan Garner
Logan is the Water Quality and Initiatives Program Manager for the Indiana State Department of Agriculture-Division of Soil Conservation. 

Unless you’re not involved with agriculture in Indiana, you’ve probably heard the term “soil health” countless times.  We are fortunate to live in a state where so many farmers are focusing on the improvement of our soils, and are adopting the paradigm that healthy soils mean good things for their crops, their wallets and the natural resources which sustain both.

Still, not everyone sees the benefits of building soil health.  There are some misconceptions about soil health as a goal which may give the impression that it does not apply to them.  For instance, some growers still ask, “if I put nutrients in my soil, then it isn’t my soil healthy?”

While putting nutrients on the ground does allow for greater nutrient availability to plants, it does not improve the soil’s inherent ability to function.  Soil health is not just about how much Nitrogen, Phosphorus or Potassium is available to a crop, but how well the soil as an ecosystem exchanges those nutrients, how well it allows water (as well as nutrients and air) to infiltrate below the surface of the ground, and how much water holding capacity lies in the soil’s structure.
Photo by Martha Miller
An excellent gauge of all these abilities is the level of organic matter in the soil.  Organic matter in the soil is ultimately a measure of carbon in the soil, but there’s more to it than that.  When carbon levels in the soil are rising, it means that things are living and metabolizing there.  Bacteria, insects, earthworms and fungi all play specific roles in facilitating nutrient exchange and availability for plant roots to tap into, and in this case the more really is the merrier.  Building organic matter also allows pores in the soil to hold its structure, which means more water can flow through the soil, and more water fills those pores.  Another way to say all that is “better infiltration and greater water-holding capacity leads to better water availability to the crop.”
Photo by Martha Miller
If all this is true, then why hasn’t everyone been doing this for years?  There’s no easy answer to this, but there are some key indicators.  First and foremost, there is little research on soil health.  A search of academic journals will quickly show that the term “soil health” is just that—a term.  However, the importance of the role of soil organic matter in soil’s capacity to sustain crops is well known.  While this lack of data on soil health may seem like a small hurdle to those who see the real, practical benefits from building soil health, it’s a flag to individuals who want to “see the numbers” before exploring the issue.  We all ought to be asking those individuals, “If given the choice between soil with low organic matter and soil with high organic matter, which would you choose?”  I don’t think a single person would pick the former.

Soil health is about the process needed to build organic matter, bottom line.  And that’s what the Indiana Conservation Partnership efforts are all about.  It’s also the end result of conservation cropping practices like a no-till and cover crop farming regimen.  It’s not about conservation program enrollment.  It’s not about participation in cropping initiatives.  Those things are tools (excellent ones, at that) which aim to reach the goal: building soil organic matter that is inherently good for production, economy and the environment.

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