[Terrapreta] FIeld and Nursery Trials

[Jim Joyner]

Tom, Let's see, 30 gallons (assuming 231 cu inches per gallon) is about 4 cu ft or 52 pounds for 85 sq feet, which is about 13 tons an acre. Be interesting to know how they arrived at that rate. It still looks like there response was positive. 

Sean, I guess I don't understand why (Cornell) aimed at yield on nitrogen fixing beans. They didn't explain. Maybe if one doesn't have a history of soil responses, that is the best one can do. I too would start with legumes just to try to build up nitrogen, to see what effect there would be on nitrogen or how much net nitrogen I could generate. But I think it is the following crops that really count. 

If we can get agriculture to the point we only have to replace the nutrients in the food we've taken out, that is a very efficient agriculture. The delusion we live with in modern agriculture is that NPK is all it takes to grow food, that we are not mining other things out of the soil.

In my experience I've applied as much as 200 tons of compost per acre, not so much for nutrient but to try to get the carbon and CEC up so it would hold the nutrient. And, it will, for a while. But then over the years (even with no-till) the carbon in the soil will literally burns off so that no matter how much nutrient I put in the soil, it is wasted because the soil can't hold it. It just washes away. This has been the bane of the organic farmer particularly in the south.

If, due to charcoal's crystalline structure (or some other magical quality), it persists, the whole game of agriculture has changed. I'm guessing, of course, but it might well be something like the paradigm shift as occurred after WWII with chemical farming.

But I digress.

I suspect, with proper amount of nutrients, one could grow in pure
charcoal -- don't know why anyone would want to, but it could be done. My guess is that the maximum quantity per acre has more to do with economics than the soil or even the crop.  

I find it interesting that terra preta can be meters deep. Plants do move elements around in the soil. By having a loosed subsoil without pans, roots will take carbon down year after year, but I doubt that accounts for the pictures of the black soil so deep. (It's just hard to think about a 2 thousand year time horizon.) 

Meters deep charcoal clearly would not be economical. It would not be harmful, and even though there would be some benefits in having biochar so deep, those benefits could be accomplished better and cheaper in other ways. For example, in Guam, after a super typhoon, we buried palm trees in land that was replanted with fruit trees. In Missouri we buried saw dust up to a depth of 6 feet (in the sub soil) before planting grapes. Both worked great for giving the plants a store of moisture and showed clear benefits over planting without. And the biomass can take decades or longer to go away.

I think, generally, it would be better to put charcoal in the soil in one shot rather many. First, the expense of doing it, not including the charcoal, is significant. Second, often such tillage or plowing is two steps forward and one back as there can be a loss of erosion control and the loss of soil structure itself. 

BTW, has anyone considered the SARE (Sustainable Agriculture Research and Education) program? They give out completive grants every year for both research and education. Their grants can be in the hundreds of thousands $ and for multi-year projects. They even have up to $10,000 grower and graduate student grants for demonstrations and just good ideas. 

The thing about terra preta research, it wouldn't seem that any one would be threatened. Until they became trendy we had a terrible time getting funding for anything "organic" because some private university funders (read chemical companies) did everything they could to stop them. But , it seems TP has something for everyone. I mean, even if it lowered the per acre use of chemicals for conventional farmers, it would still probably make agriculture as a whole, grow. It might even make up for the loss of the obscene subsidies large American farmers get (at least I hope they lose them).

Jim




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