Means and ways of engaging, communicating and preserving local soil knowledge of smallholder farmers in Central Vietnam

Increasing interest in farmers’ local soil knowledge (LSK) and soil management practice as a way to promote sustainable agriculture and soil conservation needs a reliable means to connect to it. This study sought to examine if Visual Soil Assessment (VSA) and farmer workshops were suitable means to engage, communicate and preserve farmers’ LSK in two mountainous communes of Central Vietnam. Twenty-four farmers with reasonable or comprehensive LSK from previously studied communes were selected for the efficacy of VSA and farmer workshops for integrating LSK into a well-accepted soil assessment tool (VSA). In field sites chosen by the farmers, VSA was independently executed by both farmers and scientists at the same time. Close congruence of VSA scores between the two groups highlighted that farmers could competently undertake VSA. Farmers’ VSA score was compared with their perception of field’s soil quality. For the majority of farmers’ perception of soil quality was consistent to their VSA score (62.5%), while the remainder perceived their soil quality was lower than their VSA score. For most farmers their assessment of soil quality using VSA valued their LSK, and the two measures were well aligned. Soil colour and presence or vulnerability to erosion were common soil characteristics mentioned by farmers and affected the final VSA score. Farmers’ participation in VSA and workshops strengthen farmers’ confidence in their LSK and provided guidance on the impact of their soil management on soil improvement and conservation. © 2022, The Author(s).