ABSTRACT
Early immigrants to North America settled mainly near the eastern coast where precipitation generally was favorable for crop production. A major drought in the US Great Plains and the adjacent Canadian provinces in the 1930s led to widespread soil erosion by wind. Overall goals of soil management regarding water conservation are to promote water entry into soil, reduce evaporation, and use the water to grow crops. Tillage influences water conservation through its effects on soil conditions that retard runoff, enhance infiltration, suppress evaporation, and control weeds. Evaporation is suppressed by insulating and cooling the soil surface, reflecting solar energy, decreasing wind speed at or near the soil surface, and providing a barrier against water vapor movement. Water conservation with clean tillage results primarily from disrupting soil crusts, providing for temporary water storage, and controlling weeds. Tillage-induced soil loosening can increase water storage in the tillage layer.
