Wednesday, June 25, 2008

Garden Char Processing

I've added some photos to Flickr on how I currently prepare my charcoal for add ing to garden soil. This is in support of the Biochar for Gardeners FAQ.

I am lightly soaking (shallow soak, lots of turning to keep surfaces moist) my charcoal to precondition it for a crush-and-chop reduction and then screening. To soak, I add soluble mineral fertilizer and fish emulsion. Once in the soil, these will stimulate biologic conditioning and will help prevent stalled plant growth due to induced N deficiency, a concern with direct use of fresh char in the garden.

Also, regarding the mineral fertilizer, I have it in the back of my mind that adding ammonium sulphate (a common ingredient in off-the-shelf soluble fertilizer formulations) to the soak water will boost water penetration. I am thinking this might help because ammonium sulphate is used hold farm chemicals on waxy plant surfaces (like thistle), and because saltier water generally tends to penetrate further and faster into problem soils. I am encouraged to think that ammonium sulphate helps to overcome fresh charcoal's water repellency, even if only to a slight degree.


Anonymous said...

A bit off topic but biochar:

Along a good part of Montana's Interstate 90 are a lot of dead or dying trees and a lot of burnt snags in fire areas across the National Forests. It looks like about half of the evergreens on the Continental Divide are dead.

Could those be converted to biochar, using transportable equipment, which then could be applied back on the soils? On many of those slopes getting the biochar into the soils would be a challenge.

Wouldn't this markedly reduce the release of CO2 to the atmosphere that will occur if these dead trees fuel uncontrollable forest fires, which is very likely given recent fire history, or if they decay, which is otherwise inevitable? And wouldn't biochar improve these soils?

Philip Small said...

Makes sense, especially for rebuilding ultisols (ie very mature, highly weathered) which have been degraded by erosion or acid rain. Makes the least sense for sites where soils are not degraded and which support sensitive, threatened or endangered plant species. For instance, extreme example, you wouldn't put char in a forested wetland which supported flytrap and pitcher plants. There are comparable upland plant-soil configurations one wouldn't want to mess with. That's why more manipulated environments (and some forestry environments are highly manipulated) tend to lend themselves better to char application.

Anonymous said...

Would biochar be more optimal processing for cattle manure solids and other livestock-origin feedstuffs than composting?

From a superficial perspective, that process would likely reduce the likelihood of transmission of the tougher infectious agents like prions far more than composting.

Anonymous said...

From the Oil Drum blog DrumBeat: August 22, 2008

Making Terra Preta Soil: Ramona's Recipe for Home-Made Dirt August 21, 2008 at 19:31:34
Making Terra Preta Soil: Ramona's Recipe for Home-Made Dirt