A History of Agriculture in India v1.c8.s1.6

v1.c8.s1.6

Physical agencies operate in disintegrating soils chiefly in the form of heat. Rocks are poor conductors and hence the effects of heat and cold extend only to a slight depth from the surface. The greater expansion or contraction of the surface produces a strain which causes a layer of rock to break off. Earthquakes, hot springs and volcanoes alter even the superficial layers of the earth's surface.