ABSTRACT
This paper summarizes the status of soil degradation in Sri Lanka. Considerable areas of soils are degraded through commercial agriculture alongside natural phenomena such as rainfall and topography. A major cause of land degradation is soil erosion by water, aggravated by land clearance and cultivation of crops at higher elevations. About 30 cm of topsoil have been removed from mid- and up-country regions during the past century. In the Wet Zone of the country, soil acidification has occurred because ammonium sulphate has been applied as a fertilizer to tea. Nutrient leaching and intensive cropping have also led to soil fertility decline and high Al-saturation and pH values below 4.0 are common. Some soils along the coast of southwest Sri Lanka have problems with acid sulphate conditions. Iron toxicity with paddy rice is observed in valley bottoms in the low-country Wet Zone. Salinity is confined to lower parts of irrigation tracts in the Dry Zone and the coastal belt. Inland salinity patches are seasonally regenerated by monsoon rains and cleaning of drainage systems. Legislation has been introduced for the protection of soils, and despite implementation constraints, an awareness of the need for soil protection is increasing among citizens of Sri Lanka.
