To correct initial soil deficiency. To replace cultivation saving labor and time. Today we are witnessing levels of soil degradation worse than any time in human history. Though there are many causes, the most damaging include deforestation, desertification, urbanization, loss of fertility from mismanagement of agriculture systems, salinization, pollution from chemicals and herbicides, and the effects of wind and water erosion on abused soils. We see ample evidence of these adverse effects on soil all over the world.
Sheet erosion occurs on the surface of soils where wind and water erosion come heavily into play.
Typically, after rain storms you will find pebbles and sediment on the soil surface appearing clean and exposed, as the top-most layer of soil has washed been washed away . Usually sheet erosion requires slope. Rill erosion is more pronounced than sheet erosion. Rill erosion results when a snow covered or frozen soil surface is rained on heavily. The topmost unfrozen fraction of the soil has nothing to hold it in place and is washed away leaving verticle grooves and ditches.