Sodicity‐induced land degradation and its sustainable management: problems and prospects

作者：Manzoor Qadir, Andrew Noble, Sven Schubert, Richard J. Thomas, A. Arslan · 发表于：Land Degradation and Development · 年份：2006 · DOI：10.1002/ldr.751 · 被引用次数：259 · 研究领域：Rice Cultivation and Yield Improvement、Soil Carbon and Nitrogen Dynamics、Agricultural Science and Fertilization

Abstract Currently at least 20 per cent of the world's irrigated land is salt‐affected. However, projections of global population growth, and of an increased demand for food and fibre, suggest that larger areas of salt‐affected soil will need to be cropped in the future. About 60 per cent of salt‐affected soils are sodic, and much of this land is farmed by smallholders. Ameliorating such soils requires the application of a source of calcium (Ca2+), which replaces excess sodium (Na+) at the cation exchange sites. The displaced Na+ is then leached from the root zone through excess irrigation, a process that requires adequate flows of water through the soil. However, it must now be recognized that we can no longer conduct sodic soil amelioration and management solely with the aim of achieving high levels of crop productivity. The economic, social, and environmental impacts of different soil‐amelioration options must also be considered. A holistic approach is therefore needed. This should consider the cost and availability of the inputs needed for amelioration, the soil depth, the level to which sodicity needs to be reduced to allow cropping, the volume and quality of drainage water generated during amelioration, and the options available for drainage‐water disposal or reuse. The quality and cost of water available for post‐amelioration crops, and the economic value of the crops grown during and after amelioration should also be taken into account, as should farmers' livelihoods,...