ABSTRACT
Conservation tillage has been called the greatest soil conservation practice of the 20th century. Conservation tillage reduces the intensity of tillage operations and allows farmers to manage crop residues on or near the soil surface. The organization of the Soil Conservation Society of America in 1945 further enhanced awareness of the need for conservation tillage research. A variety of planters and drills were manufactured in the 1970s that made it easier to plant into heavy residues as well as into dry, hard soils. The feasibility of planting into unplowed soil and leaving residues on the surface were especially enhanced by the development of these new herbicides which provided alternatives to cultivation for controlling weeds. Conservation tillage methods, when compared to inversion tillage methods, usually reduce soil erosion losses from agricultural lands but not necessarily the volume of runoff. Soil erosion is a function of erosivity and erodibility.
