Micro-organisms decompose rock-dust from the surface of tiny particles and combine this with organic matter to form humus. The rejuvenated soil supports an enormous variety of soil organisms, some of which capture nitrogen from the air and make it available to plants. The plants grow nutrient-rich and withstand pest and disease infestations much better. Because the plants develop an extensive feeder root system, they are also better able to withstand dry spells.
By utilising the soil organisms, it's a natural renewable energy source to process nutrients for plants. Sustainable farming makes use of on-farm resources and natural biological processes.