Compost is vital for nutrient depleted soil, however in the tropics, nutrients tend to leach out dramaticaly and the addition of any kind of fertilizer is highly inefficient.
Therefore charcoal aka pyrogenic carbon, biochar is vital in tropical soil systems.
Charcoal can be added directly to soil or into the compost heap itself. First we beat the charcoal to get it to small particles of no more than 1cm in diameter, then we mix about three sacks or more into into the compost pile. The compost pile also consist of vegetation, kitchen scraps and animal manure. We also add two layers of calcium and two layers of phosphorus rock dust. This mixture is mixed well with added water to get the optimal moisture for decomposition and placed in a one meter by one meter wide compost pile maintained by sticks (picture coming soon)and piled about 1.5 m high. The compost is checked for temperature and moisture periodicaly and and only mixed and re-moistened if deemed necessary.
Temperature is important and I like to make sure it gets very hot especialy when using manure (from our farm). By monitoring the temperature I can determine what stage the compost is in. I monitor it by inserting a machete into the heap and leaving it there for a while. Once I remove it I consider it hot (thermophile stage)when it is so hot that I have to remove my hand quickly, and I consider it warm (active stage) when the machete doesn't feel burning hot but comfortably warm to the touch.
Idealy when the heap cools down it is inocculated with beneficial bacteria (more on that later) and worms. Finding worms in my area has been a challenge so that is something I have been able to do yet.
Here I post a picture I took a few days ago when I sent my soil to be tested. I have two samples, one is virgin soil from our farm that has not been manipulated, and the other is treated soil (two years old), with carbon and organic fertilizer. It has only been fertilized twice in the last two years.
