But in agricultural lands, only one kind of plant is returned to the system. This means the set of food resources is limited for bacteria and fungi in the crop field. After a single plow event, with only one plant species returned to the system, a few species of fungi and bacteria do go extinct locally, because the food they need is no longer put back into the soil. But for the most part, all the suppressive organisms, all the nutrient cyclers, all the decomposers, all the organisms that re-build good soil structure are still present and continue to try to do their jobs. Because a good savings account of organic matter had been built up in native grassland or forest soil.
Disturbance is a part of every system, and the system has a way to manage after disturbance.
But agriculture continues to mine soil organic matter, and kill fungi, by tilling. The larger predators are crushed, their homes destroyed. The bacteria go through a bloom, and blow-off huge amounts of that savings account of carbon. The predators that keep bacteria, fungi and root-feeding organisms in line are lost. Disease-suppression declines, soil structure is lost, water infiltration decreases because mineral crusts form, and water infiltration is reduced.