Time For a Scribble.
Time For a Scribble.
From notes I wrote while listening to Dr Johannes Lehmann.
Biochar - or black carbon, has now been found all over the world. This is due to it's natural occurence via fire. however, the char differs from site to site and is nowhere found in such concentrated quantities as in the amazon basin.
Char sites globally range in age from 500 - 8000 years before present (BP). Char WILL decay. The rate of decay seems to be largely determined by the portion of labile carbon in the soil. (labile = turns over rapidly, not stable, typically new organic amendments).
That being said, char in an organic garden looks likely to have several centuries of life. The mean residence time of char, taking into account both terra preta and fire deposits, is estimated to be 2000 years.
Pyrolisation, thermal degredation, heating in the absense of oxygen. These are one and the same thing.
Cellulose, lignin and sugars become aromatic carbons during the process of pyrolisation. The original material still resembles what went in, but chemically, it is profoundly changed.
Char fresh from pyrolisation has a very low CEC around 20 mmol. But, once it has been exposed to microbes oxygen and soil the CEC has been recorded as high as 2000 mmol. Char should be amended with compost ASAP before being used in the garden.
Pyrolisation temperatures affect the pH of your char. The best temperature is 350 C. Above this causes basicity and below acidity. 350 will give you char in the pH 5.5 - 6.5 range right where you want it.
Starting with 100% biomass, you will lose approx 75% mass during pyrolisation, and then half the remaining mass will be biochar (the other half gases, so second burn them!).
Soil saturation of char is very high, with no diminshing returns recorded in up to 30% char content soils. Beginning with 5% content, char plays significant roles in soil in several areas.
Increased crops - if your soil is perfect this aint gonna happen, for most soils, char will improve yield significantly.
Increased nutrient retention. Char soaks up nutrients as well as housing microbes.
Lowered GHGases. 73% reduction in N2O, not to mention all the carbon sequestered.
Lowered nutrient runoff, with increased retention comes decreased runoff, win win for the grower and the environment.
Char is indeed inhabited by microbes and fungi grow into it, but it does not neccesarily increase microbial diversity (I'd argue this point but got too much on). It is said it does increase microbial specialisation. Sure could do with clarification on that loaded little statement.
Hope that answers a few unanswered questions.
Time For a Scribble.
From notes I wrote while listening to Dr Johannes Lehmann.
Biochar - or black carbon, has now been found all over the world. This is due to it's natural occurence via fire. however, the char differs from site to site and is nowhere found in such concentrated quantities as in the amazon basin.
Char sites globally range in age from 500 - 8000 years before present (BP). Char WILL decay. The rate of decay seems to be largely determined by the portion of labile carbon in the soil. (labile = turns over rapidly, not stable, typically new organic amendments).
That being said, char in an organic garden looks likely to have several centuries of life. The mean residence time of char, taking into account both terra preta and fire deposits, is estimated to be 2000 years.
Pyrolisation, thermal degredation, heating in the absense of oxygen. These are one and the same thing.
Cellulose, lignin and sugars become aromatic carbons during the process of pyrolisation. The original material still resembles what went in, but chemically, it is profoundly changed.
Char fresh from pyrolisation has a very low CEC around 20 mmol. But, once it has been exposed to microbes oxygen and soil the CEC has been recorded as high as 2000 mmol. Char should be amended with compost ASAP before being used in the garden.
Pyrolisation temperatures affect the pH of your char. The best temperature is 350 C. Above this causes basicity and below acidity. 350 will give you char in the pH 5.5 - 6.5 range right where you want it.
Starting with 100% biomass, you will lose approx 75% mass during pyrolisation, and then half the remaining mass will be biochar (the other half gases, so second burn them!).
Soil saturation of char is very high, with no diminshing returns recorded in up to 30% char content soils. Beginning with 5% content, char plays significant roles in soil in several areas.
Increased crops - if your soil is perfect this aint gonna happen, for most soils, char will improve yield significantly.
Increased nutrient retention. Char soaks up nutrients as well as housing microbes.
Lowered GHGases. 73% reduction in N2O, not to mention all the carbon sequestered.
Lowered nutrient runoff, with increased retention comes decreased runoff, win win for the grower and the environment.
Char is indeed inhabited by microbes and fungi grow into it, but it does not neccesarily increase microbial diversity (I'd argue this point but got too much on). It is said it does increase microbial specialisation. Sure could do with clarification on that loaded little statement.
Hope that answers a few unanswered questions.
