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What is soil pollution?
The contamination of soil with solid waste, chemicals (through industrial wastes or acid rain), fertilisers and pesticides, reducing its fertility, is called soil pollution. Also Read Chemistry Formulas
Types of soil
Soil is broadly classified into the following three types :
- Sandy soil: It contains more sand (90%) and less clay (10%). It is permeable to air and water due to large pore spaces, which dry up very easily. It is suitable for fruits and vegetables.
- Clayey soil: It has a high proportion of clay. It becomes sticky in water. It is not aerated (air spaces). Roots find difficulty in penetrating, and it gets waterlogged in high moisture. It becomes suitable for farming by adding sand over time.
- Loamy soil: It is a mixture of sand and clay together with silt and humus. It is most suitable for plant growth.
Why is tilling of soil important?
- Allows the roots to penetrate deep into the soil.
- Allows easy breathing of roots.
- Tilling loosens the soil, which helps in the growth of earthworms and other microbes, which further turn and loosen the soil.
- Adds humus to the soil.
- Brings about nutrient-rich soil to the top, so that plants can use these nutrients.
Sources of soil pollution
The main sources of soil pollution include:
- Solid wastes: The solid wastes coming from residences, cattle sheds, industries, etc. make the surroundings dirty and pollute the soil.
- Chemicals: The industrial wastes consisting of a lot of chemicals are generally dumped in vacant sites, and they pollute the soil. Some chemicals discharged into the air eventually come down as dry deposition or as acid rain and pollute the soil.
- Excess of fertilisers and pesticides: Fertilisers and pesticides, when used in excess in agricultural fields, pollute the soil. From the soil, many non-biodegradable chemicals (e.g., DDT) even enter the food chain and show biological magnification.
Harmful effects of soil pollution
- Soil pollution reduces the fertility of soil, leading to a reduction in crop yields.
- Solid waste makes the surroundings dirty and also emits a foul smell due to their decomposition.
- Soil pollution may kill and reduce the diversity of organisms living in the soil, including the earthworms, micro-organisms, etc., which are instrumental in making the rich humus.
SOIL EROSION
Soil is a complex mixture of non-living materials and living organisms. It provides anchorage to plants and is also a source of nutrients and water to the plants. The majority of the plants, thus, grow in the soil. The top layer of soil is very fertile and is often carried away by environmental agencies.
This removal of the top layer of the soil from one place to another by certain agents such as strong winds or fast-flowing water is called soil erosion.
Causes of soil erosion
The various causes of soil erosion are:
- Strong winds: Strong winds carry away the loose topsoil when it is uncovered.
- Heavy rains: Heavy rains or frequent floods wash away unprotected topsoil down into the streams, rivers, etc.
- Improper farming and suspended cultivation: Farmers loosen the topsoil of agricultural fields for cultivation or for removing the weeds. Sometimes, due to certain reasons, when these fields remain uncultivated for a long time, it becomes prone to erosion.
- Human activities: Large-scale deforestation by humans leads to soil erosion.
Effects of soil erosion
The various effects of soil erosion are loss of fertility, desertification, landslides, floods, etc.
Prevention of soil erosion
Certain measures can effectively reduce soil erosion. These include intensive cropping, sowing grasses in uncultivated land, terrace farming along the slopes of hilly areas, making embankments along the river banks, etc.
Soil Pollution: Important Information
| Aspect | Details |
|---|---|
| Definition | Soil pollution is the contamination of soil by harmful chemicals, waste materials, and pollutants that adversely affect its quality, fertility, and ability to support life. |
| Meaning | It occurs when toxic substances accumulate in the soil, making it unhealthy for plants, animals, and humans. |
| Main Causes | Excessive use of pesticides and fertilizers, industrial waste, mining activities, plastic waste, sewage disposal, oil spills, and improper waste management. |
| Major Pollutants | Pesticides, herbicides, chemical fertilizers, heavy metals (lead, mercury, cadmium), plastics, industrial chemicals, and radioactive substances. |
| Sources of Soil Pollution | Agriculture, industries, urban waste, landfills, mining operations, construction activities, and accidental chemical spills. |
| Effects on Soil | Reduces soil fertility, destroys beneficial microorganisms, alters soil structure, and decreases agricultural productivity. |
| Effects on Plants | Stunts plant growth, reduces crop yield, affects nutrient absorption, and may lead to contamination of food crops. |
| Effects on Animals | Animals may ingest contaminated plants or soil, leading to poisoning and health disorders. |
| Effects on Human Health | Exposure to polluted soil can cause skin diseases, respiratory problems, nervous system disorders, cancer, and other health issues through the food chain. |
| Environmental Impact | Loss of biodiversity, contamination of groundwater, ecosystem imbalance, and reduced agricultural sustainability. |
| Role of Pesticides | Excessive pesticide use introduces toxic chemicals into the soil, harming beneficial organisms and reducing soil quality. |
| Role of Industrial Waste | Industrial effluents and chemical waste release hazardous substances that accumulate in the soil. |
| Role of Plastic Waste | Plastics do not decompose easily and remain in the soil for hundreds of years, affecting soil health and water movement. |
| Prevention Measures | Proper waste disposal, recycling, organic farming, reduced use of chemical fertilizers and pesticides, afforestation, and treatment of industrial waste before disposal. |
| Control Methods | Bioremediation, phytoremediation, soil reclamation, composting, and sustainable land management practices. |
| Importance of Soil Conservation | Conserving soil ensures food security, environmental sustainability, biodiversity protection, and healthy ecosystems. |
Quick Facts About Soil Pollution
| Fact | Information |
|---|---|
| Type of Pollution | Land Pollution |
| Most Common Cause | Excessive use of chemical fertilizers and pesticides |
| Major Effect | Loss of soil fertility |
| Affected Resources | Soil, groundwater, crops, and ecosystems |
| Best Prevention Method | Sustainable agriculture and proper waste management |
| Environmental Concern | Threatens food security and biodiversity |
Key Points to Remember
| Point | Explanation |
|---|---|
| Soil is a vital natural resource. | It supports plant growth and food production. |
| Polluted soil affects the food chain. | Toxic substances can enter crops and reach humans and animals. |
| Industrialisation increases soil pollution. | Improper disposal of waste leads to contamination. |
| Organic farming helps reduce pollution. | It minimizes the use of harmful chemicals. |
| Soil conservation is essential. | Healthy soil is necessary for sustainable development. |