Degraded Soils

Abstract

Soils are used in many different ways including agriculture, horticulture, forestry, agro-forestry, pasturing, foundation engineering, mining, ceramics, pottery, medicine, and in many other purposes. Agricultural soils are used for cropping, livestock rearing, and other types of biomass production. In whatever way the soils are used they need some sort of management; and we often mismanage soils while doing so. Misuse and mismanagement of the soil include cultivation of marginal soils, inappropriate tillage, use of heavy machinery for cultivation and harvesting, faulty irrigation and drainage systems, improper use of agrochemicals including fertilizers, lime and pesticides, removal of crop residues, continuous cropping, deforestation, overgrazing, etc. Misuse and mismanagement of soils lead to soil degradation and desertification. Although soils have some capacity or resilience to return naturally to their original state if some minor changes have occurred, soils suffering from human induced degradation cannot usually regain their productive capacity without some sort of conservation and rehabilitation efforts. So, soil degradation needs to be prevented well ahead of its reaching to an irreversible state. Where degradation is moderate, rehabilitation of the soil can be technically and economically feasible. When irreversible degradation takes place, it is almost impossible to return it to a meaningful productive state. About 2 billion hectares of agricultural land have been abandoned due to soil degradation since farming began; these lands are now bare wastelands. Over exploitation and mismanagement have converted many drylands in arid, semi-arid and dry subhumid areas into desert-like lands. The process is popularly known as desertification. Desertification affects 3.6 billion hectares of rain-fed croplands, rangelands, and irrigated lands. However, some efforts of desrtified land rehabilitation are encouraging.