Nature and Causes of Soil Pollution

Agricultural Soil Pollution

Pollution of Surface Soil

Includes disturbance of surface soil in terms of its structure, chemical properties and biological activities due to agricultural activities such as cultivation of crops, irrigation, application of fertilizers and pesticides.

Such pollution has created problems such as

Salinity of Soils

Indiscriminate use of irrigation coupled with imbalanced use of fertilizers and poor drainage has caused salinity in more than 1 million hectare of agricultural land. This has rendered the soil unfit for production. Excess salts of sodium (NaCl, Na₂SO₄, Na₂CO₃), calcium (CaCl₂, Ca₂SO₄, CaCO₃) and magnesium (MgCl₂, MgSO₄, MgCO₃) are deposited in soil surface due to faulty agricultural activities and they do not allow the soil to function in normal way. Such soils cannot support the growth of crops.

Loss of Fertility

Continuous addition of fertilizers without any regard to its dosage, balance between nutrients and requirement of crops has caused loss of fertility - although fertilizers are supplied to improve the nutrient status of soil. Soil has been rendered by modern method of fertilizer usage as a mere physical media to supply the nutrients - whenever nutrients are added by fertilizers. But, in its natural condition, soil is a combination of physical, chemical and biological media - where in an equilibrium is established between physical structure, chemical nature and biological activities of soil. Continuous application of fertilizers and pesticides has damaged the soil structure, altered the chemical reactions and disturbed the biological activities to create imbalance. Hence, in long run the soil has lost its inherent capacity to produce and supply the nutrients.