Improving soils through biochar: the water bed method

The daffodils are blooming everywhere here in the Delta. Spring is coming, but the winter rains are hanging on, keeping us from doing much in the garden–except making biochar.

Biochar is the most revolutionary change in farming since organic methods. Biochar improves soil health by improving soil structure, increasing organic matter, reducing soil acidity, reducing the need for chemical and fertilizer inputs and increasing drought resistance. Most importantly to farmers, biochar increases productivity and crop yields. If you aren’t familiar with biochar, read this article and you’ll want to try it.

Comparison of traditional rainforest soils with biochar plot. Source:

We especially like it down here in the Delta because our soils are much like those where biochar was first found. Five hundred years ago Spanish explorers, winding their way through the Amazon River Basin of South America, came upon an interesting phenomenon.  Due to high rainfall, most rainforest soils are leached of plant nutrients and organic matter.  However, periodically the explorers would find small patches of black, highly productive soils.  Upon further investigation they found that these patches were created by local Indian tribes using the partial burning of biomass.  They made these soils from biochar (charcoal).

There are fancy ways of making biochar using pyrolysis in closed containers, but we like quick, easy ways that don’t require any equipment except our trusty shovel, rake and pitchfork.

Water stands on our soils nearly all winter. We have to build them up in raised beds if we want to get any early crops in. Since we have plenty o’trees growing on our property, biochar is the perfect method for us.

We have developed a unique method which might also work for you if you have wet soils and trees you need to thin out. We call it the water bed method because it uses our plentiful winter water and beds.

We start by double digging the soil in dry weather (digging in wet weather just leaves huge clods). We dig down about a foot. We pile all the topsoil in one bed leaving a ditch beside the bed. The ditch fills with water in the wet winter.

As we are cutting firewood in the winter, we haul the branches over next to the new ditch. Then, on a nice still, cold day, we light the brush pile on fire. We enjoy the warmth of the bonfire, but don’t let it get too fierce. We don’t want all the wood to burn up, we just want to turn it into charcoal. When one section of the brush pile has burned down to charcoal, we push it into the water filled ditch. The pleasant sizzle of hot charcoal hitting water means the wood has quit burning and we have just contributed a little biochar to our next bed.

When the winter rains lessen in Spring, we cover the now biochar filled ditch with soil from the side of the plot where we burned the branches. Since it was burned, it has no grass or weeds to deal with. Nice clean soil for our next bed is what we are putting on top of the biochar filled ditch. And we are creating a new ditch for our next biochar prodution phase.

It’s a simple easy method for us. And fun. We have an excuse for nice bonfires in the winter when everything is cold and wet. And we know we’re doing something productive with all that wood waste. It will be soil in the Spring. A resilient soil which can be planted early.

If you create biochar, you’ll be creating the most resilient soil system. As shown in the rainforest plots in the Amazon Basin, biochar appears to sequester carbon for hundreds if not thousands of years.  It is resistant to the microbial breakdown that is common with crop residues and other types of soil organic matter.  Crop residues break down in a couple of years and humus oxidizes in less than 25 years.  So, biochar is not subject to the “leakage” that is a concern for carbon sequestered with no till farming and the carbon capture and sequestration of fossil fuel carbon emissions 

You’ll be countering global warming. Biochar has been shown to reduce the soil emissions of nitrous oxide (as a greenhouse gas, it is 310 times more potent than carbon dioxide) and improve the uptake of methane (21 times more potent than carbon dioxide).

Biochar has a unique ability to reduce atmospheric carbon levels. 
Biochar production takes plant based carbon that originated from the atmosphere through photosynthesis and sequesters it in the soil. 

Plus its a great way to spend a clear winter day when you want to be outside and you want to be warm. Start a fire and make biochar!

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