Sunday, March 10, 2013

Terra Preta: The Savior of the Western World

A better soil

Although I have posted about the use of terra preta before, the time has come now that the blog is far more popular and trafficked to post again in hopes that other people begin attempting this process.

Terra Preta, in short, is soil (whatever soil that may be) which has been improved through adding a significant (up to 33%) content of roughly ground up charcoal to it, along with, normally, compost and sometimes other materials (the "authentic" terra preta in the amazon rain forest seems to have a great deal of pottery sherds in it, along with bone fragments.)

The natives of the Amazon were using this method in the precolumbian period for almost a thousand years, eventually blanketing, if reports are true, a total land area twice the size of Great Britain in this improved soil which would have given them the capability to sustain enough agriculture to have been, at the time, perhaps the largest producer of foodstuffs on the planet, rivalling even latter day Rome in overall productivity.

The soil has numerous benefits.

1. It increases crop yields by 25 to 45 percent over regular techniques involving crop rotation- which is almost as good as, and sometimes better than, traditional chemical fertilization.

2. The soil regenerates itself over time- up to a centimeter per year, as microorganisms within the soil degrade organic content and amass layer upon layer of fertility. It thus actually increases over time, while most soils degrade when used for agricultural purposes.

3. It sequesters carbon- not only is the production of the charcoal added to the soil carbon neutral or carbon negative, but the combination of microorganisms continually adding carbon rich content to the soil, plus the stable carbon input to the soil, combines to sequester massive amounts of it- it has been guessed that terra preta is stable for up to 5,000 years, and as it increases over time in layers it may be infinitely stable.

4. Added to drainage areas it could potentially stop leeching of chemical fertilizer into water sources.

5. As it was being created on a massive scale a thousand years ago by natives using primarily stone tools and inefficient methods, it has to be assumed that any advanced nation could create enough terra preta in a decade to cover all of its arable land.

6. In agricultural areas, topsoil carbon content is being depleted- this would reverse the process and make the soil even more fertile than it was to begin with.

7. Nutrient leeching is minimal in such improved soils.

Were the western nations to use this method over even fairly small areas (10%) of agricultural land, it would increase yields, decrease reliance on eastern-produced chemicals, protect the environment, and could lead to carbon neutrality.

It has been proposed that through such methods, this could also be used to make extremely poor soils (such as those in the steppe of Texas, or perhaps even deserts) arable enough for at least crops which require minimal water.

Less intensively, gardening enthusiasts can easily make charcoal using a 50 gallon steel drum to make charcoal through a process you can find here.

I will be experimenting with terra preta this year using the following recipe.

1. Ground charcoal via 50 gallon steel drum- mixed into soil at the rate of about 25% for the top six inches. The charcoal will not be soaked in chemical fertilizer or compost tea as some recipes suggest is useful, to test whether this step is truly necessary (studies show that for a short time after application the charcoal reduces rather than increases available nutrients. If this proves problematic, soaking in bonemeal and an overlayer of compost will be used.)

2. One pound of organic bonemeal per drumload.

3. Half a drumload of organic compost (homemade) per drumload of charcoal.

4. The use of crop rotation and perhaps green manure.

5. Optionally, half a drumload of cow shit per drumload of charcoal.

All of my garden beds except for one are raised and have already had significant amounts of organic compost added to them from my own compost pile.

In one area, the terra preta will consist of 33% charcoal, 33% organic compost, twice the bonemeal input, and 33% regular soil (which in my location is mainly a loose, almost loamy mix, which has somewhat more silt and somewhat less clay than actual loam.)

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