AGRICULTURE NEWS - In the early days of agriculture across the world, when soil was tilled for the first time, it tended to have a considerably higher humus content than today.
Cultivation aerated the soil, stimulating microbial life.
The energy source of these microbes was the organic carbon which, when digested, released nitrogen into the soil solution for use by crops. At the same time, carbon was released into the air.
All a farmer had to do was add any other nutrients that might have been lacking, such as potassium, phosphorus or calcium.