Land & Soil degradation involves the effect on biophysical environment by human-induced processes that are implied on the land. Soil is uppermost layer of the earth. Degradation is due to the loss of soil through erosion or through the loss of soil fertility. The replacement of primary vegetation (Climax) with secondary vegetation alters the composition and amount of humus in soil.
According to an estimate up to 40% of the world's total agricultural land is seriously degraded.
The plants growing on the ground forms the humus and checks the lowering circulation of the matters. It serves as barrier in soil erosion as the roots of plants hold the soil. Man can negatively affect soil and land by his harsh actions, such as clearing, reckless cutting of trees, litters raking etc.
Erosion is due to several reasons as water, wind, chemical and physical degradation. Based on human activity erosion also happens due to laying new roads which increase impermeable surfaces that would cost loss in ground. Agriculture also increases the risk of soil erosion by increase of field size, planting of one type of crop over the years, row cropping, tilling or plowing, overgrazing of animals in meadows.
The use of herbicides kills the weeds in between crops thus leaves the ground naked between each crop. The use of chemical Fertilizers rather than organic manure gradually destructure the soil. Thus the land productivity decreases because of land degradation. The immensely increasing population is causing land shortage.
Land degradation not only affects soil fertility but also it affects rivers, wetlands and lakes since soil, with nutrients and other contaminants are delivered in large quantities to environments.
Some more causes of land degradation involve Irrigation and overdrafting, Urban sprawl and commercial development, Land pollution including industrial waste and Vehicle off-roading.
Soil erosion or loss of fertility of soil decreases crop yields; increase in cost of production, land abandonment.
Soil tillage is the principle cause of degradation of cropped fields. Soil tillage causes rapid breakdown of soil organic matter. Therefore to avoid land and soil degradation soil tillage must be reduced, leave as many crop residues as possible, and replenish the nutrients removed by the crops.
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