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The View from Here: In the (crop)field

Mike Gangwer Published on 30 June 2014

During a recent trip east of my duty station here in New York, I happened to stop along the roadside and walk to a cropfield. Here, I found the magnificent example of our biosphere in one place. As I stood there, I realized again the wonder of the world that is a cropfield.

I am not a fan of the abstract … and we may define the abstract in this case as an instructor standing in front of a classroom and showing a PowerPoint presentation of a particular topic.

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Yes, PowerPoint software has its place, but it is used incorrectly so often that I find it disturbing. Yet at a recent four-day training session, every presentation was based on a PowerPoint file.

In the not-so-distant past, our soil scientists would dig a soil pit about 3 or 4 feet deep, and we learned by looking at the surface and subsurface soils, the roots, the channels, the soil animals and the older residue. For many people, this experience was so enlightening because the entire biosphere can be examined. That is, the rooting depth and plant canopy.

Unlike the abstraction on a computer screen, the actual examination back then yielded learning – real understanding of the flux and flux densities of the biomass.

I have fond memories of watching our young soil conservationists and soil and water conservation district employees discover the relationship of the organic and the inorganic, the layers of compaction and the void space with water or atmosphere, the old carbon root from a tree having been fallen decades ago, the relationship between above-ground and below-ground biomass, the maze of material that may or may not be organic and the overall structure of the soil-plant organization.

We would then leave the soil pit and walk upslope and downslope, we walked to the depressional areas, and we walked to the fencerow or the edge of the field, where there is a surface channel. We examined the soil texture and see where the deposits were made.

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And we thought about the soluble portion of runoff that is gone. We introduced the unity equation, and here it was manifest with abstraction as infiltration and interception, and runoff at the edge of the field.

We talked about the rate of infiltration and what is the role of rate as a function of land use and compaction, and crop cover and residue. We examined the above-ground biomass and wonder about the canopy and the leaf surface and the quality of light as solar radiation.

We examined the labile pool of nutrients below the ground even as we now understand how they move through the root into the shoot and then assimilate in the plant as growth.

We could not then and cannot now do all of these in the classroom. Yes, we can introduce topics and ideas, but only in the field can we truly learn.

Our objective today is not reductionism but systems thinking. All farmers think in systems thought. That is, a farmer thinking about cover crops does so in the context of the entire biosphere over a period of five to six months. An instructor tasked with delivering cover crop training must explore the biosphere comprehensively using a systems approach.

The cover crop instructor can teach the entire topic from a single photograph if the classroom setting is all that is available. A better approach is to obtain a cubic-foot monolith and bring it into the classroom. We had done this several times when going to the field is not an option.

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We used to tear apart the monolith and examine the soils and roots and residue and crop biomass. We got our hands dirty. And we quickly discovered we must think about this cubic foot of soil as a very small subsystem of the entire biomass.

What I am making the case for is understanding and not the measurement of a particular metric. I am less concerned with the actual soil test phosphorus value as I am with understanding the various pools of phosphorus, which one is like the laboratory extraction, and what is the fate of phosphorus application that includes much more understanding than just soil chemistry.

I am less concerned with the actual transpiration ratio as I am with understanding what are the various conditions that help us use water beneficially.

What I am making the case for is a fundamental understanding of why systems thinking is essential so we may know that using a single reductionist approach – say, crop yield – is incomplete without knowing how the biosphere works.

We do this in the field. In the soil pit we can empirically work through and therefore combine the soil-plant-atmosphere continuum and the water flow through it as flux, and over time, as flux density.

We do not need to measure anything at this level. We are working through processes and changes in energy and mass over a time frame of an hour or month or entire growing season.

Only when we have the Soil-Plant-Atmosphere Continuum (SPAC) and water fundamentals can we then begin to understand the role of measurement, either as direct or indirect, either in the field or in the laboratory, and then can we understand that for one particular metric, it is influenced by other components in the system.

I am thinking now about our current college graduates. I hope they are building knowledge based on individual systems in their first and second year. In the third, they shift to integration of these, and then in the fourth, a complete examination of the biosphere as a comprehensive and systems approach based upon field experience and empirical observation.

Why the biosphere? Simply because it feeds us, we build on it, we breathe in it, and it is the most dynamic system on the planet’s surface. For those of us working with farmers in the realm of conservation, we must have an essential understanding of the SPAC and the water flow through it. It is the basis of everything we do in our role to help implement Title II of the farm bill.

This article came to me as I stood here and looked at this very field. How I wish there could have been 25 new employees with me, and we would not lecture but learn, not sit but walk across the field and its border, not already think we know but actually know because we are here in the field.

And to be sure, after our field work is done, and we gather in a circle to wrap up our visit, I am certain there will be more questions than answers, and in the group, I hope there will be a few that think about this knowledge as art. That while we may try to explain the components of the biosphere and see them empirically, there is much we do not know.

Thus it is in the realm of art that we enter and humbly admit that being here as a participant and a seeker is just as important as the knowledge we gain by observation. In fact, the older I am, the more I can see but struggle to understand.

I submit that all good field scientists struggle as well. PD

  • Mike Gangwer

  • Agricultural Scientist
  • USDA-NRCS
  • Email Mike Gangwer

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