干旱区生态环境知识资源中心

The natural resource base of land, water and vegetation in arid and semi arid areas is highly fragile and extremely vulnerable to degradation. Increasing population along with the demand for more food, fodder and fuelwood has given rise to a chain of interrelated economic, social and environmental issues associated with the land degradation. Desertification is essentially a result of soil degradation. A variety of natural and human factors are contributing to desertification, including drought, overgrazing, over exploitation of land and water resources, over cultivation of marginal lands, deforestation, soil erosion, water logging and salinity and the use of inappropriate agricultural technologies. The consequences of this are: abandoned croplands, affected by waterlogging and salinity; abandoned villages, traditional irrigation systems and croplands desertified by deteriorated groundwater aquifers or lowering of the water table; siltation of rivers, irrigation systems and reservoirs; landslides in hilly areas. The desertification leads to agricultural productivity losses and enhance poverty. It also causes significant reductions in carbon storage in soils, contributing to global warming, and loss of biodiversity. Various approaches are being applied to combat the menace of desertification. Introduction of rapid growing exotic species of trees and grasses for stabilization of shifting sand dunes; creation of microclimates through shelterbelt plantation have proved highly successful towards the control of desertification. Sustainable land management (SLM), soil and water conservation, afforestation and rehabilitation of degraded land, repetitive high resolution satellite images, delineation and mapping of affected areas, remote sensing and geographic information systems (GIS) arc likely to be suitable strategies for combating desertification in Pakistan. The efforts already underway to combat desertification need to be strengthened and integrated through a nationally supported, coordinated and monitored system.