Soil degradation is the change induced by the natural decrease in the soils' potential for productive use. It normally results in reduced yields due to lack or insufficiency of nutrients and water available for plant growth, or higher costs and decreased efficiency of added nutrients.
Improper land use and poor land management technologies have been singled out as the most important factors leading to soil degradation. However, the main contributing factors are the economic conditions of poor farmers often exacerbated by agricultural policies that discourage farmers from adopting improved procedures of management, and access to markets for their produce. Examples of policies that contribute to land degradation include commodity-based subsidies, controlled (fixed) prices on agricultural products, taxation policies that encourage the use of marginal land.
Degraded land can be rehabilitated in a cost-effective manner through improved land management practices such as ensuring soil cover with organic matter, proper fertilization, rotation, and good irrigation practices. Best estimates are that 562 million hectares (38%) of the global agricultural land area are degraded. However, severely degraded land is generally not cost-effective to rehabilitate.
At the international level, several high profile initiatives aimed at improving the use and conservation of the world's natural resource base and preserving a healthy environment, including addressing land management issues - have been taken during the last decade. The three UN Conventions resulting from the Rio Summit - on Combating Desertification, Slowing Climate Change, and Preserving Bio-diversity - have helped direct global attention to soil fertility deterioration and productivity decline as the most serious factors contributing to environmental degradation.
The World Bank has recognized the significance of land degradation and the loss of soil fertility and is mobilizing programs to correct the problem. In the recently updated Rural Development Strategy, the Bank emphasizes the critical need to urgently improve the management of natural resources, including integrated soil fertility management.
The complex challenge of preventing and rehabilitating degraded land requires technical, political and social mobilization to ensure the implementation of improved land management practices in a cost effective and sustainable manner. That requires a high level of sustained commitment by governments to address and resolve the important issues. Government should, for example promote a favorable policy/incentive environment, and encourage and facilitate the active participation of farmers and their organizations in such programs.