Semantics from Central Valley Ag on Vimeo.

by Mike Zwingman

by Mike Zwingman

For a long time, friends, we’ve talked about soil texture or type.  Maybe you have a Hastings silt loam out in your fields, or a Nora Moody Croftin clay loam.  You definitely know your soil type because we’ve been talking about it forever.

Somewhere along the line, a long time ago again, we began to make a small but important error while talking about our soil type though: we started to use type and structure interchangeably, as if they are synonymous.

They aren’t.

Don’t accuse me of potato-potahto just yet.  I’m usually not one to pick on language, but in this case, the erroneous way we equate soil type and structure has some negative consequences on our actions.  So, I’m hoping to put a little fix to how we use these words today.

You’ve probably noticed that I’ve got three words in this mix here: texture, type, and structure.  Go ahead and use texture and type to mean the same thing.  We could get picky about it, but let’s not.  Because let’s save that parsing for structure.  Structure is not type or texture.  That’s important.  Here’s why:

Whatever soil type you have out there, there’s not much you can do to change it.  That type has been determined by eons of forces that take us way back past the glaciers.

Whatever soil structure you have out there though, there’s quite a bit you can do to change it.  In fact, you can impact it quite negatively in a matter of hours.  (Of course the negative impact is quite expedient; as you might guess, the positive impact isn’t as speedy.)  Anyhow, our ability to change soil structure, as opposed to our inability to change soil type, is the key point here and the important distinction that gets lost when we use the terms interchangeably.

Because we really can’t have a great conversation about water or nutrient efficiency without understanding something about our soil structure and how to improve it.

Soil structure is the formation of aggregates of different shapes and sizes and a good structure lends to a list of very desirable soil characteristics like good water holding capacity, high water infiltration rates, improved nitrogen mineralization, and improved cation exchange capacities.

When we mistake structure for type, we lose the understanding that we have quite a bit of control over the health of our soil and its ability to perform well for us and our crops.  While our soil type was determined slowly over millennia, our soil structure is determined by current and daily forces like wetting and drying, freezing and thawing, microbial activity, organic matter, and whatever diversity of roots and soil animals is present in it.

What’s that you say?  You don’t control the freeze/thaw cycles?  Or the sun and rain?  Well cheers, friend.  That is true.  But the rest of that sentence above—microbial activity, organic matter…diversity of roots and soil animals—you do have quite a bit of control over.  And those are the key elements of good soil structure, or what we might also call here soil health.

I know that when I talk about soil health and the brown revolution or whatever that it can be easy to dismiss as weirdo conservationist talk.  I was pretty dismissive for some time, too, but when you get past the hippy sound of it, it’s really quite practical talk about getting our soil to give maximal support to our endeavors to make a living and feed our families, communities, and, you know, the rest of the world, too.

One reality is that probably none of our soil is maximally healthy, or structured.  Years of common practices, like constant tillage, put us here.  But what’s been done is done.  And it’s reasonable now to take steps to improve our soil structure so that we can reap the benefits of maximally healthy soil.

I’ve been pretty clear that this year, my goal is to help you improve your nitrogen and water efficiency.  If you’re on board with me, I’m asking for your engagement now, step one of which is attention to the difference between soil type and structure.  Where we’re going, we need a vocabulary for.  If you’re not on board, I might just ask for your openness to a different way of doing things.


Wherever you land, let me end with a plug for a new article series from CVA, On Point, by my good friend Keith Byerly.  This series will be devoted to precision technologies and water—closely related to my topics, but more laser-focused on this one precious resource.  If you’re one of those growers already on board, we hope his articles give you more ideas and perspectives from which to view the future.  For those of you still on the fence, or still on the other side of the fence, we hope that another perspective might help you consider the benefits we so clearly recognize in improving your management of nitrogen and water.