At AbonoChar LLC we use a fine grade of hard-wood horticultural charcoal in "BioPreta™"
Since biochar carbon remains in the soil for so many years, we call "BioPreta™" a “Permanent Soil Restoration”. You put biochar in your soil once, and it stays there. You can add more, and it will stay there. That saves you a lot of money!
Carbon is an element that is the chemical basis of all known life. Charcoal has been known since the beginning of civilization and is a soft, brittle, lightweight, black, porous material that resembles coal. Charcoal can be made of many materials called “biomass”. The difference between charcoal and biochar is the way it is used. Charcoal is used as a fuel or as a filter among other things. Biochar is specifically used in the soil for agriculture. Because typical commercial BBQ charcoal is sometimes mixed with chemicals for outdoor cooking, it is not a good idea to put it in your soil. Biochar is carbon. Carbon is what gives healthy soil its dark color.
Biochar and charcoal are produced by heating (baking, not burning) biomass until the moisture and volatile gases have escaped. This process is more like baking in a pizza oven at 500-600 degrees F than it is like burning biomass in a fireplace. The ancient methods involved burying wood under a layer of clay and limiting the air to the burning pile.
When biochar is placed in the ground it attracts soil microorganisms, bacteria and fungus, and other valuable living things into its pores.
If biochar is applied alone it may actually attract important soil nutrients away from plants while it gets established.
That is why "BioPreta™" is a blend of biochar and VermiCompost™.
Plants inhale carbon dioxide (CO2) and exhale oxygen (O2), leaving carbon behind. (CO2 – O2 = C)
That is how carbon is captured in the plants and is one way that carbon in the soil actually increases over time. Some of the carbon, of course, leaves when we harvest our crops, and we need to put carbon back where it came from.
The story "The Mystery of Terra Preta de Indios" tells of how biochar has remained in the soil for thousands of years. This is one way we can reverse the carbon dioxide in our atmosphere. Planting trees is a great way to reduce the carbon in the atmosphere, but when trees die and decompose the carbon returns to the atmosphere. By putting carbon in the soil for thousands of years we can remove it from our atmosphere. When we burn fossil fuels and wood we add carbon to the atmosphere. Wood ash has been considered good for the soil as it reduces acidity, but burning down the forests just adds carbon to the atmosphere.