1-Soil is the thin top layer on the earth’s crust comprising rock particles mixed with organic matter.
2-Pedology is the study of soils in their natural environment.
3-The soil is formed by the breaking down of rocks by the action of wind, water and climate.
4-If soil contains greater proportion of big particles it is called sandy soil.Water can drain quickly through the spaces between the sand particles. So, sandy soils tend to be light, well aerated and dry.
5- If the proportion of fine particles is relatively higher, then it is called clayey soil.Clay particles, being much smaller, pack tightly together, leaving little space for air. Unlike sandy soil, water can be held in the tiny gaps between the particles of clay. So clay soils have little air
6-Clayey and loamy soils are both suitable for growing cereals like wheat, and gram. Such soils are good at retaining water.
7-For paddy, soils rich in clay and organic matter and having a good capacity to retain water are ideal.
8-Loamy soils, which drain water easily, are required for lentils (masoor) and other pulses
9-Sandy loam or loam, which drain water easily and can hold plenty of air, are more suitable for Cotton.
10-A vertical section through different layers of the soil is called the soil profile.
11-A soil horizon is a layer generally parallel to the soil surface, whose physical characteristics differ from the layers above and beneath.
12-Soil texture refers to the proportion of the soil separates that make up the mineral component of soil.
These separates are called sand, silt, and clay. These soil separates have the following size ranges:
Sand = <2 to 0.05 mm
Silt = 0.05 to 0.002 mm
Clay = <0.002 mm
13- Sand and silt are the inactive part of the soil matrix, because they do not contribute to a soil’s ability to retain soil water or nutrients