Thursday, September 6, 2007

New Age Global Agriculture

When I started this blog, I had one very important arrow in my quiver. That was the knowledge that it was becoming feasible to produce a small stand alone solar atmospheric water harvesting device capable of daily producing a 100 liters of water per day.

This would be sufficient to support a growing tree in any arid desert were the humidity was high enough. Of course that means all deserts since one would start at the humid rim and slowly advance into the desert effectively bringing the natural humidity with you. This terra forming of the desert would naturally support a cropland fraction and an extensive animal husbandry among the trees and orchards.

We can easily globally double the available land under agricultural management in this way and sequester a huge amount of carbon.

I then extended this approach to current agricultural practice and developed an economic model for bringing agricultural waste land under managed forest practice were atmospheric water harvesting is less important.

An underlying assumption for both approaches was that current practice would not be modified very quickly and that no good solutions for soil improvement were at hand. But we could live with that since we had done so for thousands of years. I was still very uncomfortable though that we were mining the soil for nutrients and that replacement strategies consisted of mining and producing minerals often in a non sustainable manner.

This also meant that desert lands would require long periods of time to reconstitute soils. Trees would be fine because they reach deep into the earth to find nutrients, but the surface would suffer. Again time and careful effort would overcome all this. A thousand years of effort and every hillside and former dry land could be fully timbered and vegetated with modest final water inputs. This is a fine dream and project for humanity to embark upon.

And then I was introduced to Terra preta. This was work that conformed to and confirmed a previous effort that I had put into Zeolites in which a great deal of field work has been done by researchers. I understood immediately the importance to the globe of this discovery. The problem was to figure out how to produce the soil.

This I was able to tentatively solve through the use of an infield carefully constructed corn stover stack kiln that would produce a ton of biochar per acre.

All of a sudden we have a method of swiftly building out soils anywhere in the world.

Let us engage in a thought experiment. Keep in mind that we cannot quite do this yet. We take a square mile of desert fairly close to adjacent agricultural land. We isolate the low lying areas (perhaps a 100 acres) as potential crop land toward which surplus water will flow. We plant tree cover with solar water harvesting devices outside these areas.

As the trees grow out, the soils begin to build up some water retention and this supports an increase in ground water finding its way into the designated crop lands. As soon as feasible we start the first corn crop. Each crop puts a ton of biochar back into the soil and several years of this attention we should have well developed soil. At that point, we continue to produce biochar which is then transported into the woodlands an integrated into those soils accelerating their maturing. If we are already running cattle, we will witness a rapid improvement in available fodder.

If the objective is to create mature soils throughout and to achieve maximum yield throughout, then at the end of fifty years every acre should have several tons of carbon in the form of char and additional living carbon totaling another twenty tons or so. This can all be done in the lifetime of an individual owner.

This is a far cry from the current situation in which we are running fast just to stay even.

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