<P> Slash - and - burn and other unsustainable methods of subsistence farming are practiced in some lesser developed areas . A sequel to the deforestation is typically large scale erosion, loss of soil nutrients and sometimes total desertification . Techniques for improved soil conservation include crop rotation, cover crops, conservation tillage and planted windbreaks and affect both erosion and fertility . When plants, especially trees, die, they decay and become part of the soil . Code 330 defines standard methods recommended by the U.S. Natural Resources Conservation Service . Farmers have practiced soil conservation for millennia . </P> <P> Contour plowing orients crop furrows following the contour lines of the farmed area . Furrows move left and right to maintain a constant altitude, which reduces runoff . Contour plowing was practiced by the ancient Phoenicians, and is effective for slopes between two and ten percent . Contour plowing can increase crop yields from 10 to 50 percent, partially as a result of greater soil retention . </P> <P> Terracing is the practice of creating nearly level areas in a hillside area . The terraces form a series of steps, each at a higher level than the previous . Terraces are protected from erosion by other soil barriers . </P> <P> Terraced farming is more common on small farms and in underdeveloped countries, since mechanized equipment is difficult to deploy in this setting . It protects the soil from its erosion . It is one of the way by which soil erosion can be stopped . </P>

What is soil conservation suggest some measures to conserve soil