Characteristics of Soil

Soil is a complex mixture of different types of materials and is derived from the rock, organic matter and other materials carried by geologic agents and biotic community. The soil characteristics depend upon its texture and structure.

Soil texture is dependent on the size of the original rock particles in the soil. Soil texture may be of following types:

(i) Sandy Soils : These contain loose and dry sand particles (particle size 1.00 to 0.05 mm) along with clay (10%) and silt (size 0.05 to 0.002 mm). Such soils are poorly aerated, have low water holding capacity and have low nutrients.

(ii) Clay Soils: These contain clay particles (size less than 0.002 mm) and inhibit free circulation of air and water. These are unsuitable for cultivation, since they become water logged easily. Clay soils contain sand, silt and clay in the ratio 2:2:1.

(iii) Loam Soils : These soils are most suitable for vegetation, since these have good aeration properties of larger particles. They contain nutrients and have moisture retaining ability. These contain sand, gravel, silt and clay in the ratio 2:2: 1: 1.

The manner in which different constituent particles aggregate with each other to form clumps determines the soil structure. Sandy soils have bigger particles, do not clump and so lack structure. Large clumps are formed if small clay particles stick together in closed packed manner. Loam soils are good soils and contain a balanced composition of large and small particles. They form clumps of reasonable size. Such soils crumble easily creating passage for air, water and nutrients.

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