Participatory-land use allocation in Besitang watershed, Langkat, North Sumatra, Indonesia

This study was conducted to develop a framework for participatory and improved land use decision-making in Besitang Watershed, Langkat, North Sumatra, Indonesia. Specifically, it aimed to: assess land uses changes, estimate soil erosion under different land uses, analyze the actual and potential suitability of the lands for several annual, estate and silvicultural crops, determine the current and potential land use suitability with stakeholder participation and develop a spatial participatory land use allocation based on integrated approach to ensure sustainability. Socio-economic information and physical data were derived from interviews and field survey. Collective opinion was derived from the workshop with stakeholders. Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) were used for land use allocation. The Universal Soil Loss Equation (USLE) was used to determines soil erosion in each land system. Remarkable land use changes occurred from 1990 to 2006. Large portion of primary forest (82%) were converted to secondary forest, followed by conversion of mangrove forest into fish pond (30%). The mean soil erosion is classified as Class 2 and large areas are under suitable land uses based on erosion index. Land capability of Besitang Watershed ranges from Class 2 to 6. The majority of land is under the land capability Class 3. Land systems with very steep slopes were not suitable for several annual and estate crops and silvicultural species. In general annual and estate crops as well as silvicultural species are not suitable (N) in the lower stream of the watershed, due to drainage and flooding hazard. Alternative for forestry in Besitang Watershed based on integrated approach has very high suitability (63%). Agriculture use has high (63%) to very high (37%) suitability. Settlement area has low (23%) to moderate (77%) suitability. Fishery use has low (47%), moderate (18%), and high (35%) suitability. Industry has a very low suitability in all decision zones (100%). Based on allocation for multiple-use, Besitang watershed has very high potential suitability for forestry (63%) and agriculture (37%) land use. The most significant contributions of integrated approach using GIS and AHP in facilitating land use decision-making were: as a tool for land use allocation and policy formulation, as well as for scientific investigations. This approach provides participatory involvement of stakeholders in land use allocation. This approach is efficient and reliable land use allocation for watershed management, since it involves the physical components as well as participation of stakeholders to ensure sustainability.