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www.GOALias.blogspot.comthis layer is the bedrock, which is hardand difficult to dig with a spade.9.3 S9.3 SOILTYPESAs you know, weathering of rocksproduces small particles of variousmaterials. These include sand and clay.The relative amount of sand and claydepends upon the rock from which theparticles were formed, that is the parentrock. The mixture of rock particlesand humus is called the soil. Livingorganisms, such as bacteria, plant rootsand earthworm are also important partsof any soil.The soil is classified on the basis ofthe proportion of particles of varioussizes. If soil contains greater proportionof big particles it is called sandy soil.If the proportion of fine particles isrelatively higher, then it is calledclayey soil. If the amount of large andfine particles is about the same, thenthe soil is called loamy. Thus, the soilcan be classified as sandy, clayey andloamy.The sizes of the particles in a soilhave a very important influence on itsproperties. Sand particles are quitelarge. They cannot fit closely together,so there are large spaces between them.These spaces are filled with air. We saythat the sand is well aerated. Water candrain quickly through the spacesbetween the sand particles. So, sandysoils tend to be light, well aerated andrather dry. Clay particles, being muchsmaller, pack tightly together, leavinglittle space for air. Unlike sandy soil,water can be held in the tiny gapsbetween the particles of clay. So claysoils have little air. But they are heavyas they hold more water than the sandysoils.The best topsoil for growing plantsis loam. Loamy soil is a mixture of sand,clay and another type of soil particleknown as silt. Silt occurs as a depositin river beds. The size of the silt particlesis between those of sand and clay. Theloamy soil also has humus in it. It hasthe right water holding capacity for thegrowth of plants.I want to know:What kind of soil should beused for making matkas andsurahis?Activity 9.3Collect samples of clayey, loamy andsandy soils. Take a fistful of soil fromone of the samples. Remove any pebbles,rocks or grass blades from it. Now addwater drop by drop and knead the soil[Fig. 9.4 (a)]. Add just enough water sothat a ball [Fig. 9.4 (b)] can be made fromit, but at the same time it should not besticky. Try to make a ball [Fig. 9.4 (c)]from this soil. On a flat surface, roll thisball into a cylinder [Fig. 9.4 (d)]. Try tomake a ring from this cylinder [Fig. 9.4 (e)].Repeat this activity with other samplesalso. Does the extent to which a soil canbe shaped indicate its type?SOIL9999