When standing water covers soil, any oxygen in the water is used rapidly, and then the aerobic bacteria go dormant. Anaerobic bacteria use ferric iron (Fe 3+) in goethite and hematite as an electron acceptor in their metabolism. In the process, iron is reduced to colorless, watersoluble ferrous iron (Fe 2+ ), which is returned to the soil.
Tillage was used for seedbed preparation, weed suppression, soil aeration, turning over cover crops and forages, burying heavy crop residue, leveling the soil, incorporating manure and fertilizer into the root zone and activating pesticides. The effect of tillage on soil However, tillage has all along been contributing negatively to soil quality.