Monday, November 10, 2008

Terra Castings

This was posted on the terra preta forum recently and I have lost the attribution. What is interesting is the observation of orchard health and a remaining layer of leaf mould.

Anyway, we are reminded of the power of the earth worm in processing and making soil. Integrating that with biochar becomes common sense.

We already know that it takes at least a full growing season for the benefits of biochar to be fully established. We may now know how to deliberately speed it up.

An earthworm with a diameter of an eighth of an inch travelling an inch an hour (I am guessing here) can process a cubic inch in about sixty four hours. That suggests that a single worm can process most of a cubic foot in a year. It is also a good bet that the earthworm heads for soil that has not been disturbed recently in order to work fresh ground.

Put in that perspective, the earthworm is actually our most important single tool for processing soil and should be actively encouraged.

Terra Castings?

I have recently learned of the use of chitin in worm composting to select for fungi that decompose chitin (insects exoskeletons). Crab or lobster shell can be used, or the shells left behind by mantis, cicadas and locusts.

Though the process is patented, there is no law stopping me from doing this at home.This greatly intensified my interest in worms! Killing larval stages of fungus gnats and root aphids with worm castings!

So I'm thinking about worms, and the use of them for fighting disease and it occurs to me the healthiest orchards I've been in left the leaf litter on the ground. Worm food, complete with any and all problems the leaves may have incurred the previous season.

I'm also looking at bio-remediation, utilising bacteria and fungal symbionts to accelerate the 'organic properties' of badly abused land. This I believe can be enhanced by char amendment, and if the char addition contains the symbiotic bacteria fungi etc needed for enhancing soil biology, it could make it a one step process.

So out comes the mortar and pestle, and some nice char which is pine hardwood and avocado pits gets ground to dust and added as carbon for the worm farm.

Results will have to wait, and it's just me in my yard.

But others could try this. I imagine it will only take a small amount of these castings to make big changes to soil structure.

Of course, the castings need to be good. That is, displaying the range and speciation desired for soil restoration. Bacteria, fungi, protozoa, nematodes. These castings can be tilled in or spread, and also used in compost teas to 'breed' multitudes of micro-herd in a short space of time for soil and foliar application.
With worm castings said to retain 10 times the nutrition of compost it makes sense to me to process char in worm farms and then apply it.

My hope is that this will alleviate the nutrient drain seen in some soils as the char will be 'full'. Also, the setting up of correct biology for organic systems. Terra Preta does not require fertiliser, mulching and compost should be all that is required, recycling the lands wastes, very minimal addition. Soils that don't require inorganic fertiliser have a complete soil food web.

So, instead of loading the char with fertiliser, inorganic or organic, I'll load it with a microherd full of chelated ready to go organic nutrients.

Can also merely change the worms diet to alter nutrient profile of the castings.

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