How does conservation tillage conserve soil, and how effective is it?
With conventional tillage (complete turning over of the soil), the bare soil is exposed to the erosive action of water, which, in many areas is the major route of soil loss. Under conservation tillage, the crop residue buffers the raindrops’ energy, so water has less erosive force when it reaches the soil. This protection by residue, along with the rougher surface provided by the residue facilitates infiltration and decreases runoff — runoff that carries soil and nutrients with it. In addition, macropores, which are the major route for water movement through soil, get disrupted in the surface 15-20 cm of soil by conventional tillage, but remain intact under conservation tillage. Improved macropore development also enhances water infiltration and decreases water runoff. Conservation tillage thus can also conserve water and fertilizers. In the midwestern US, farmers get consistent reductions of about 75% in soil loss when corn residue is left on the surface compared to losses under conv
