The multiple land degradation effects caused by land-use intensification in tropical steeplands: A catchment study from northern Thailand

摘要: The strongly incised mountain landscape of northern Thailand has changed dramatically during the last few decades due to increased population pressure, agricultural commercialization, limitation use old fallows and reforestation upper catchments. traditional shifting cultivation with fallow periods 7 years longer was gradually replaced by 1 4 year periods. As a result, in high areas became dominated fields planted rainfed upland crops, wetland rice terraces, vegetation, patches secondary forest. This new land-use system seems have triggered land degradation processes that are easy observe when travelling through this landscape. objective research assess multiple effects intensification tropical steepland environment on processes. A case study conducted at Pakha village (located Thailand's most Chiang Rai province), which is average slope gradients ranging from 30 70%. Soil erosion were monitored selected catchment for 2 years, informal interviews elucidate farmers' perceptions regarding rapid changes Dze Donglo (164 ha) resulted severe accelerated degradation, including tillage (386 ton/year), inter-rill rill (502 gully (423 landslides (7572 ton 1994). Water common intensively farmed areas. combination runoff-generating areas, runoff-concentrating features connectivity led extensive erosion. Landslides steep terraces along incising streams. Many these interacted each other (i.e. rills erosion, water gullies landslides). observed matched very well perceptions. enabled identify potential hotspots indicates necessity analyze holistic way. (Resume d'auteur)