The nature and management implications of landsliding on irrigated terraces in the Middle Hills of Nepal

In the wetter areas of the Himalaya, irrigated terraces for the growing of rice (paddy) are the mainstay of the agricultural economy. Increasing popul ation pressure is encouraging farmers to change from a single irrigated cro p to double irrigation of terraces and from rainfed (bari) terraces to irri gated terraces. This change places a premium on the efficient use of the, o ften dwindling, water supply. As this study in the Middle Hills of Nepal ha s shown, irrigated terrace risers often experience extensive slope failures . Although such failures are relatively insignificant in land degradation t erms, they are labour intensive with respect to remedial measures and creat e management problems. The results also suggest that it is the recent conve rsion of bari terraces to irrigated terraces that are experiencing most pro blems. There is also the implication that the landscape has almost reached the point where further expansion of irrigated terraces is unsustainable. I f food production is to be increased, other cropping systems will need to b e considered, with more attention being paid to the sustainable use of rain fed terraces.