Soil structure and soil organic matter are influenced by the crops grown the residue or manure returned, and the tillage-planting system. The objective of tillage operations is to prepare a fine, firm seedbed capable of rapidly warming under sunshine, and once achieved there is no advantage to additional tillage. The conventional answers to the objectives of tillage may include such reasons as the burial of trash, to loosen soil, reduce kill weed lump size, destroy hardpans, increase moisture infiltration, improve appearance, increase soil temperature, incorporate chemicals, and avoid condemnation by peers. Some of these reasons are sound; others are not.