Soil Conservation on Sloping Land: Technical Options and Adoption Constraints

This chapter briefly summarizes the causes and consequences of soil erosion, before presenting examples of effective soil conservation technologies (SCT), such as contour-based cropping, cover crops, mulching and geo-textiles, and based on case studies from northern Thailand and northern Vietnam. Depending on site conditions, a soil erosion reduction of 30–60 % in the first year after establishment and up to 72–98 % by the third year was observed in these studies when compared to local farmers' practices. In north-east Thailand, maize grain yields increased from 1.5 and 3.2 Mg ha−1, to 3.8 and 5.5 Mg ha−1 under minimum tillage und relay cropping. The study in north-western Vietnam revealed that although the majority of farmers were aware of soil erosion mitigation methods, adoption rates of the promoted soil conservation technologies remained low. These technologies compete for land and labor resources with the main cropping activities, in particular highly profitable commercial maize cultivation, incurring high opportunity costs. Based on these case studies, we conclude that innovative approaches to soil conservation require a change in land use systems, not just the adoption of conventional SCT in the existing systems. The integration of plant and animal production in the uplands should be promoted that allows farmers to benefit from urban-based economic growth on the one hand, such as through the exploitation of niche markets for high-value meat, while being environmentally sustainable on the other. The improved integration of animal husbandry with plant production systems could make feed producing soil conservation options more attractive to farmers, which could be further stimulated by introducing payment for environmental services (PES) schemes.