As the plants grows, the soil microbes work with the plant to support, feed and protect the plant. Once it is finished its growing cycle, or there is a disruption to its growth, (damage, excess moisture, application of fungicides, herbicides, etc.) the soil microbes become the clean up crew and decompose the plant tissue. Current agronomy often looks at specific microbes and the numbers associated with those microbes, whereas we look at the soil health and resilience. 

Healthy soil with Air, microbes and carbon will recover faster than soil condition that lack these characteristics.