Land is the most vital and heavily threatened natural resource in Sri Lanka. Degradation of land due to soil erosion is of much concern because of its consequences on agriculture, which is a major contributor to the country's GDP. It is estimated that about 5-10 mm of topsoil is lost every year. In the hill country, where several large rivers originate and critical watersheds are located, erosion is acute. Many land use practices, past and present have reduced the productive capacity of soil and land in the country. The process of soil erosion commenced in the 19th century with the expansion of human settlement and cultivation of upland rain fed crops.

This was aggravated by the changes in land use patterns during the British administration, when upper catchments of major rivers located in the central highlands were stripped natural vegetation to were stripped natural vegetation to make way for plantation agriculture such as coffee and tea. Land clearing continued even after independence primarily for the establishment of human settlements. Some direct and indirect factors that contribute to soil erosion are :

• Chena cultivation (slash and burn cultivation), practiced in about 15 percent of the total land area.

• Insecure land tenure, with rotation of cultivation by plots and by season, also causes degradation of land because land is exploited to the maximum with minimum conservation measures.

• The increasing rate of deforestation.

• The cultivation of erosive crops such as potatoes, tobacco and vegetables has led to severe erosion particularly in hilly areas.

• Sand and gem mining, construction of roads, housing projects and other infrastructure Comparative studies of erosion by zone have shown that mid country is the most prone to soil erosion. Out of 25 administrative districts of the country, in 07 the estimated land area under erosion is over 40% ( Kandy - 41%, Ratnapura - 42% , Moneragala - 42.5%, Hambantota - 42.8%, Badulla - 54.8%, Trincomalee - 55%, and Nuwara Eliya - 58%) both on site and off site impacts occur due to erosion.