3. What are the properties of soil?
Answers
Properties of soil are:
1. Texture of the soil
The texture of the soil depends upon the relative amount of these particles. Clay has the smallest sized particles. Because of very small size, the clay is felt smooth. Silt particles are larger than the clay particles. There size range from0.002 to 0.02mm in diameter. So silt does not feel smooth. Sand particles are largest sized particles of soil. Their diameter is more than0.02mm.
2. Absorption of water in the soil
Water holding capacity in different types of soils is different. Soil absorbs water because it is porous. Sandy soil holds less water than clay soil and loamy soil. Clay soil holds more water than sandy soil. Sand absorbs less water than clay. Some plants require more water to grow; they grow well in clay soil and loam soil, since sand hold less water, so less vegetation is found in sandy soil.
3. Moisture in the soil
Texture decides the water holding capacity of the soil. The soil has some amount of water inside it as a moisture. Water is usually present as a thin film around the soil particles. It is absorbed by the roots of the plants. The capacity of a soil to hold water is important for the growth of various crops. Even a dry soil has some water in it.
4. Colour of the soil
Soils are of different colours. They are red white and black. The red colour of the soil is due to the presence of iron oxide. The black colour soil is rich in minerals and humus. It is good for the growth of wheat and jowar
5. Soil pH level
Soil can be acid, alkaline or neutral. Some plants grow in acidic soil (pH below 7) such as potatoes and kumara. Carrots and lettuces prefer soil with neutral pH (7.0). Soil become more acidic over time as minerals are leached away.
6. Percolation Rate in the soil
When we sprinkle water on the ground, it is soon absorbed by the soil. This is because water percolates through the soil. The process in which water passes down slowly through the sol is called percolation of water. But water does not percolate at the same rate in all types of soils.
Sandy soil allows maximum percolation of water and clay soil allows minimum percolation of water. Rainwater percolates through the soil and collects above the bedrock. This level of groundwater is called water table. Sandy soil is quite loose, so the percolation rate of water is highest in sandy soil but lowest in the clay soil because it is very compact.
Paddy (rice crops)is planted in standing water in the fields. Hence, the soil with a low percolation rate of water would be the most suitable for growing paddy because it will allow the water to remain in the fields for a much longer time.
7. Soil contains air
Air is present in the space between the soil particles. This air provides the oxygen required for respiration by roots of plants and other organisms. Sand particles are quite large. Sand particles cannot fit closely together, so there is large space between sand particles.
The large space between sand particles is filled with air. Due to this, sandy soil provides much more air to the plant root. But clay particles pack tightly together leaving little space for air. So, clayey soil provides much less air to the plant root which grows in it.