Local soil knowledge, sustainable agriculture and soil conservation in Central Vietnam

Efforts to support farmers living near forests to achieve sustainable agriculture and natural resource conservation have predominantly focused on services or schemes such as agricultural extension and community-based forest management, with little attention being focused on farmers' local soil knowledge (LSK). This paper provides insights into farmers' LSK, their agricultural and soil conservation practices and economic reliance on natural forests. Household survey (n = 146) and key informant interviews (n = 24) with farmers was conducted in two communes of the buffer zone of Bach Ma National Park, Central Vietnam. The results indicated that 70% of farmers had reasonable LSK, and farmers with comprehensive LSK (21%) were more familiar with their soils and the relationships between essential soil properties that reflect soil problems. Most farmers used soil colour to allocate crop types because of its association with soil fertility or plant yields. Erosion was identified as a major production constraint, yet less than a fifth of farmers had placed soil erosion control measures into practice. However, low-cost techniques, such as growing native plant cover (e.g.“lồ ô” (Bambusa balcooa)), were suggested by a few farmers to address soil loss. The Katu farmers had greater potential to secure LSK as the next generation are continuing to farm, while the Kinh farmers' LSK is threatened by a lack of engagement in farming by the younger generation. However, Katu farmers have less opportunity to use their LSK due to limitations in farm size and cropping options. These findings have raised different challenges to the succession of farmers' LSK for sustainable agriculture and natural resources conservation in the two communes. Finally, this study highlighted the importance of involving farmers' LSK in the early stages of designing and conducting research through forums or workshops to improve relevance and adoption of practices developed so they align with local people's understanding and practice.