The multiple land degradation effects of land-use intensification in tropical steeplands : A catchment studty from northen Thailand

Turkelboom Francis, Poesen Jean, Trébuil Guy. 2006. The multiple land degradation effects of land-use intensification in tropical steeplands : A catchment studty from northen Thailand. In : Conference "Environmental change, geomorphic processes, land degradation and rehabilitation in tropical and subtropical highlands, 19-25 September 2006, Mekelle, Ethiopia. s.l. : s.n., 30 p. Conference on Environmental Change, Geomorphic Processes, Land Degradation and Rehabilitation in Tropical and Subtropical Highlands, Mekelle, Éthiopie, 19 Septembre 2006/25 Septembre 2006.

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

Classification Agris : P36 - Érosion, conservation et récupération des sols
P01 - Conservation de la nature et ressources foncières

Auteurs et affiliations

• Turkelboom Francis, ICARDA (SYR)
• Poesen Jean, Physical and Regional Geography Research Group (BEL)
• Trébuil Guy, CIRAD-TERA-UPR GREEN (JPN) ORCID: 0000-0002-1370-4731

Source : Cirad - Agritrop (https://agritrop.cirad.fr/538627/)

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