Farming system changes in the Vietnamese uplands - using fallow length and farmers' adoption of Sloping Agricultural Land Technologies as indicators of environmental sustainability

摘要

The environmental sustainability of the farming system changes during the 1990s of two villages in the northwestern Vietnamese uplands was assessed by an analysis of changing fallow length practice and farmers' adoption of Sloping Agricultural Land Technologies (SALT) in relation to slope steepness. The fallow length change detection involved an identification of the vegetation succession stage of the fallow vegetation at the time of clearance and was based on high resolution satellite image classifications. The use of SALT was surveyed by ground registration and overlaid with a digital elevation model. The results were coupled with an assessment of farmers' ability and willingness to adopt SALT in order to detect changes in attitude and perceptions amongst the farmers regarding their future agricultural strategies, and a discussion of the level of livelihood diversification in the villages. The study illustrates the complexity of the development situation in the Vietnamese uplands and emphasises the importance of locally adapted development strategies, suited to the traditional farming systems of the ethnic upland communities. The methodology for the analysis of changes inrnfallow length based on satellite images offers promising potential for the use of remote sensing technology in the assessment of environmental sustainability of shifting cultivation systems under change.