Agroforestry for sustainable management of soil, water and environmental quality: looking back to think ahead.

摘要

In India, the increasing demographic pressure coupled with developmental activities are causing tremendous pressure in the utilization of the natural resources leading to various kinds of ecological problems and land degradation. The increasing frequency of these disasters and ecological problems is the outcome of excessive biotic and abiotic interferences that have resulted into considerable degradation of our natural resources. The Government of India has accorded highest priority to the holistic and sustainable development of rainfed areas and wastelands (107 million ha) through watershed development programmes. Agroforestry with the active involvement of watershed community plays an important role to meet the challenges of shortages in food, fodder, firewood, timber, pulpwood, and employment generation and ensure sustainability of production systems. More than two decades of investment in research and extension have clearly demonstrated the potential of agroforestry for resource conservation and improvement of environmental quality. The examples are the studies on: (i) vegetation cover influence on runoff and soil loss in reforested watersheds in Doon valley in Uttar Pradesh (28% runoff and 73% peak discharge reduction) and Nilgiris in Tamil Nadu (16.0 and 25.4% reduction in water yield during first and second rotation of bluegum (Eucalyptus globulus) plantation over natural grasslands); (ii) negligible runoff (3.5-8.0%) and soil loss (2.3-3.0 t ha-1 year-1) under agrosilvopastoral system in Meghalaya; (iii) reduction in runoff (from 40 to 30%) and soil loss (from 21 to 8 t ha-1) in hedgerow intercropping in Doon valley; (iv) increase in vegetation cover and reduction in sediment load (from 320 to 5.5 t ha-1 year-1) in treated landslide and mine spoil watersheds in outer Himalayas; and (v) increased dry weather flow (from 100 to 250 days) due to stabilization of landslides in a hilly watershed. The role of agroforestry for sustenance of soil, water and environmental quality is discussed through examples from India and highlights some issues, which need to be addressed to meet the future challenges..