About 2 billion ha in the world is affected by various forms of human induced land degradation with erosion by water being the chief contributor (1.1 billion ha). In India, out of 120.8 million ha (Mh) degraded land, 82.6 Mh is estimated to suffer with water erosion, 24.7 Mh from chemical degradation, 12.4 Mh due to wind erosion and 1.1 Mh from physical (mainly due to stagnation of water) degradation. About 6.73 Mh is adjudged as salt-affected. With developing scenarios of severe water scarcity and competition from other sectors of economy, it appears axiomatic that agriculture would have to increasingly depend upon marginal and poor quality waters. In most of the arid and semi-arid regions the ground water aquifers are saline. The groundwater surveys indicate that poor quality water utilized in different states of India ranges between 32 and 84% of the total ground water development.

To meet various diverse needs of ever-increasing human and animal population, we need to be rehabilitate all degraded lands. Many species of forest and fruit trees, shrubs, forbs, grasses and medicinal plants have been identified and evaluated for growing in problematic areas. Vast tracts of arid and semi-arid areas remain barren due to salinity or water scarcity. With use of appropriate planting techniques and salt-tolerant species these could be brought under viable vegetation cover. Auger-hole technique for sodic soils, furrow technique of tree plantation for saline soils, and ridge plantation in waterlogged fields are found quite appropriate. By applying appropriate planting and management techniques (e.g. sub-surface planting and furrow irrigation), various species of forest and fruit trees, forage grasses, medicinal and aromatic and other high value crops have been found equally remunerative. Tree-based technologies have additional environmental benefits including huge amount of carbon sequestration, biological reclamation and mitigating climate change.