- Soil helps plants in their growth by providing them with water and nutrients. There is a great importance of soil in agriculture. Agriculture helps in satisfying the need of food clothing and shelter to all.
- The survival of plants is very essential, because they are prime producers, as they can prepare their own food in the process called as photosynthesis. Animals are dependent on plants for survival. Thus animals are indirectly dependent on the soil for survival and nourishment.
- We get minerals and metals from soil.
- The soil has the capacity to hold water. Rainwater gets collected between the gaps of rocks and this water is available for us for use throughout the year.
- Thus we can say that soil is important for the survival of plants and animals that is for the survival of all living beings. Hence the soil is a natural resource.
- As soil is a natural resource and nonrenewable resource, it should be conserved.
- A disturbance in the natural balance of the various components in the soil is called soil pollution and the soil is said to be polluted. It directly affects crop production and thus indirectly affects human nutrition and the quality and utility of soil.
- Cadmium, chromium, copper, pesticide, chemical fertilizer, weed, toxic gases etc. are major soil pollutants.
Causes of Soil Pollution and Remedies:
- Chemical fertilizers are soluble in water. They react with minerals present in soil and thus causes salination of the soil. Excessive use of fertilizers and pesticides results in accumulation of these chemical substances which get mixed with groundwater resulting in water pollution. To prevent soil and water pollution the use of chemical fertilizers and pesticides should be restricted. Instead of the use of chemical fertilizers, organic manures and natural insecticides and pesticides should be used. Use of organic fertilizers increases the fertility of the soil.
- When water let out from industrial zone mixes with soil, soil pollution takes place. This can be avoided by treating the effluents before they are let out.
- Due to acid rain soil pollution takes place.
- Excessive use of water decreases fertility of the soil.
- illegal dumping of debris, electronic goods, broken plastic furniture, junk papers, polythene bags, plastic cans, bottles, wastewater, toxic waste from the hospital etc. pollute the soil. In such cases wherever possible recycle and reuse practices should be used.
- Continuous drilling in mineral oil and oil wells, continuous mining, nuclear and radioactive waste, are more dangerous activities and soil pollutants. The products of such activities should be disposed of in proper scientific manner.
- The removal of the top fertile layer of the soil from the soil is called soil erosion. It is a naturally occurring process that affects all landforms.
- It takes place in three steps first soil detachment, second the movement and third the deposition. Topsoil, which is high in organic matter, fertility and soil life from one place is relocated elsewhere at the shallow basin. Here the soil it builds up over time and fills in drainage channels.
Causes of Soil Erosion:
- Rainwater falling on the soil. The intensity of rain increases the extent and the rate of erosion. The impact of raindrops on the soil surface can break down soil aggregates and disperse the aggregate material. The lighter aggregate materials like fine sand, silt, clay and organic matter get removed by the impact of raindrop and runoff water. The rate of soil erosion is noticeable during high intensity rin pour. The soil erosion due to less intense rain is not noticeable over a short time but its effect can be seen over a long period.
- Fast current of water flowing on the soil.
- Gust of wind
- The possibility of soil erosion increases for a land which has less vegetative cover. Thus less vegetative cover is one of the main cause of soil erosion.
Types of Soil Erosion:
- Rill erosion results when surface water runoff concentrates in the region where the soil is loosely attached compared to rest of the region. Small yet well-defined channels are formed from where the soil has been washed away. These channels are called rills. When the width of the rill erosion increases it is referred as gully erosion and it becomes an alarming factor.
- Natural streams like rivers and constructed channels act as outlets for surface water runoff. Bank erosion is a progressive undercutting, scouring and slumping of these drain ways.
- When water penetrates through a soil hole created due to the decay of root, the soil disperses and is carried away with the flow to leave a small tunnel. Initially, the surface is intact but with a continuous flow of water the size of the tunnel increases. Ultimately it collapses to form gully.
Mass Movement of Soil:
- Mass movements like soil creep, earthflow, slumping, landslips, landslides and rock avalanches occur on cleared slopes in coastal and hilly areas. The soil starts moving under the action of gravity it may be slowly or sudden.
- It is most likely to occur in a region where strong winds blow over light-textured soil which has been heavily grazed.
Steps to Avoid Soil Erosion:
- Erosion of soil from baren land is more, hence the soil must be kept covered by growing grass and planting trees on it. The grass reduces the speed of flow of water and minimizes direct contact of water with soil.
- The erosion of soil on sloping land is more. Hence the soil should be arranged horizontally across the line of the slope so as to reduce soil erosion.
- Bunds should be built to stop flowing water which washes away the soil and causes erosion. Similarly, contour canal can be dug across the flow of wtaer.
- To prevent soil erosion land should be vegetatively covered. Grass and trees should be grown on barren lands. Forests should be conserved. Thus forests should be saved from destruction. To increase the forest land and to motivate common man, the government started a social forestry plan. People are motivated to plant trees in all possible places, such as borders of fields, both sides of the road, railway tracks, on banks of rivers, streams etc. Adivasis and small farmers have been given incentives to increase their participation in the scheme.
- Using these barren lands are reclaimed for agriculture. There is an increase in green cover.