Hi, sorry it took me so long to respond, but I've been kind of busy.
I'm really glad you liked my post, and you got to read it.
The truth is that this process is similar to the one you mentioned, the oven is covered with soil, and there are different ways to do it, for example the wood can be stacked vertically, also horizontally.
The carbonization process is the best, the kiln is similar to a small smoking volcano, unfortunately I couldn't take pictures of this process, but when I can go again, and if I have the possibility I will take pictures to show you.
And also as you say, some farmers use coal to enrich the soil, and good as a fuel source in places where access to natural gas is almost impossible. My family has been working with this for many years, and it is the major part of the economy of this field.
That is really cool! I thought your post was great!