Why are there different kinds of soil?

Different soil - the basic materials of the surface of the earth is solid rocks and the surface of the landscape we see is nearly always the result of weathering the action of sun, wind, frost, rain, ice or snow. Therefore there are many kinds of soil depending upon the climate and the type of parent rock. There is also a third factor which influences the kind of soil formed. This is the vegetation. The first step in weathering is the breaking down of the rock. Water plays an important part at this stage either by freezing and shattering the rock as it expands or by washing away some of the mineral of which the rock is composed thereby loosening its particles. The climate is also important for most rocks contain much quarts as well as silicates. In a cold climate, the crystals of the silicates are dissolved more quickly than the quartz. In a hot moist climate however, the quartz is washed away and the silicates left behind. Every intermediate stage can be found between this two extreme types of soil. Vegetation also plays its part by splitting rocks with its roots. Also dead branches and leaves fall on to the ground, decay and add a layer of humus to the soil rich in nutrients which enable larger plants to grow. These larger plants support animals some of which help to mix the soil still further. There are other types of soil such as those formed the silt deposited by rivers alluvial soils or where bogs and marshes occur. But one thing is common to all soils. They are very unstable if the vegetation which covers them and aids in their formation is removed. Then they are easily washed away and the result of centuries of slow development is lost.