Saturday, January 23, 2016

Got Tilth?

The shallowness of rivers out east (like the Patuxent) is a result of the relatively small drop in elevation from the headwaters to the continental shelf, which is relatively broad and shallow on the Atlantic coast. Our land in Southern Maryland is part of the Coastal Plain formed from ancient ocean sediments topped by glacial till. In more recent times, logging and agricultural practices allowed humus-laden forest soil to be washed into the rivers, leaving silty river bottoms and depleted sandy soils for today's farmers.

If you don't want to assume that you have sandy soil, it is worth taking half an hour to perform a simple test of your soil's texture. Soil texture is the most important feature of soil health. You want soil that is loamy in order to grow most crops. In performing the steps in the flowchart, use soil from a 6-inch band underneath any loose organic matter (the O layer) that may be covering your garden. This A layer would also be the soil layer to use for collecting samples to send to a lab for occasional soil tests. Lab tests are necessary to know how to correct for most nutrient deficiencies, but initial adjustments to soil texture (based on your ribbon test results) are foremost.
Texture_by_feel_analysis_DecissionTree-bw.png

Thing about adjusting soil texture is that it is difficult in the short-term. You can't just throw sand into a clay soil to make loam. It might become hard like concrete. If you add loads of compost to sand, you will lose a majority of the nutrients and humus to leaching. Correcting the nutrient and textural deficiencies of a sandy soil through amendment with compost will require about 100 years of incremental compost additions. The best way I know to address non-ideal soil texture is to add biochar.  In the case of sandy soil, which will have nutrient deficiencies due to leaching, the biochar should be pre-composted in order to capture some nutrients and imbue it with a thriving population of microbes. Biochar should reduce the time required to correct texture problems by a factor of 10.

In preparation for winter storm Jonas, I emptied my rickety, elevated, wood drying rack of kindling into a huge pile. Doing so helped me to see that I could dry a whole lot more kindling by making this my usual practice, because the wood will stay dry in such a large pile. Heretofore, my biochar production rate had been limited by my drying rack capacity. Now, I could easily double my production rate by charring simultaneously with two kilns once I have a steady reserve of dry kindling piles. As with last year, 2016 looks like it will bring another Moore's Law improvement to my biochar productivity. Anyone in my area want to purchase some biochar? Or do you have 100 years worth of patience?

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