Rehabilitating degraded land

Success stories in land management are well documented: agroforestry, conservation agriculture, soil fertility management, regeneration and water conservation. In fact, the new report states that the economic case for land restoration is strong, with benefits averaging ten times the costs, even when looking at very different types of lands and communities of flora and fauna. A common feature of many of these success stories is major involvement by indigenous populations and local farmers.

And yet these achievements remain far short of the scope of the problem. Significant obstacles remain – including, according to the report, increasing demand for land, lack of awareness of the extent of land degradation, fragmented decision-making within and between countries, and increased costs of restoration as time goes by.

Most countries are experiencing serious land degradation, directly or indirectly associated with deforestation, drought, floods, cultivation of marginal land, overgrazing and poor range management, overpumping of aquifers, alkalinization of soils, volcanic eruptions, and a number of other occurrences that remove, impair or render useless soils and their beneficial vegetation and organisms. Desertification, erosion, siltation, land subsidence and climatic changes may follow.

This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities. Agenda 21 recommends rehabilitating degraded land as part of an overall programme of land conservation and rehabilitation.

Soil is the depending factor in land rehabilitation. Once vegetation has been removed the incoming sunlight and rain remain in place. As soil varies from place to place the specifics of each place have to be considered. In areas where only a few centimetres of top soil hold all the mineral nutrients, once this has been blown away or eroded then seedlings can only be established with great difficulty and intensive care. Other lands with fertile soil hundreds of metres thick revegetation will prove to be easier. If salt has been brought into the root zone rehabilitation will depend on plants that can tolerate salinity. Where there is moving sand the plants which are needed to halt the sands will be different from those which will flourish best when the land surface has stabilised.

The international township of Auroville, India has been developed on a severely eroded coastal plateau, the result of two hundred years of deforestation, bad land management practices and over-grazing. When the community commenced its restoration settlement in 1968, the land was visibly dying -- deeply scarred with gullies and ravines, depleted topsoil and with virtually no vegetation. Initially thousands of kilometres of bunds (raised earth banks) and ditches were built to catch and hold rain water and control runoff, thus encouraging percolation and recharging of the underground aquifers. Check dams were built to catch the remaining runoff and existing catchment ponds were desilted and enlarged to augment the area's water holding capacity. Over the years the bunding became more systematic and comprehensive and was increasingly determined by local watershed patterns.

Auroville's tree planting programme took off in earnest in the early 1970s. Tree species were eventually selected for such characteristics as drought resistance, rapid growth, capacity for soil enrichment, economic viability and, in the case of ornamentals, shade and beauty. Hundreds of different species of timber, ornamentals, fencing shrubs, firewood, fruit and fodder trees, including many exotics, were introduced. Special methods of plant raising and care were developed, particularly protection of young plants from grazing animals and foragers using living thorn fences and human patrols. As the trees grew and micro-climates formed, many species of migratory and resident birds returned, also accelerating natural seed dispersal. Over two million trees now occupy the 1,000 hectare site.

1. Vast areas of land have been so misused in the past that they are no longer capable of growing food and fuel for the people that live there. In such critical situations trees have a significant contribution to make to land rehabilitation; in many cases their contribution will be decisive. This is about the most important job trees have today.

2. No land rehabilitation programmes can succeed without land redistribution. A precondition of rehabilitation methods to be effective is that the rural landless and the small peasants have an enduring stake in the land.