Maintenance of soil quality and sustainable production through implementation of conservation agriculture production systems (CAPS) in rainfed, sloping land farming of the mid-hill region of Nepal

A challenge that central mid-hills communities in Nepal face is maintaining soil fertility and health in upland terraced systems while simultaneously achieving increased productivity and avoiding soil degradation. To determine the effect of conservation agricultural production systems (CAPS) on soil quality and productivity, replicated on-farm experimental plots with a control, legume sole crop, legume intercrop, and reduced tillage treatments were established in three villages of the Trishuli River watershed area. Soil physical and chemical properties were assessed to examine inherent differences among villages that will contribute to success/failure of CAPS. The villages differed in characteristics: high %silt, Mg2+ saturation, and Mn concentration (Thumka); high Ca2+ saturation and bulk density, low porosity and %clay (Hyakrang); stoniness, high %sand, %OM, %N, and effective cation exchange capacity (Khola Gaun). Although no significant differences in yield after two years of cultivation under CAPS were present, significant differences among villages occurred, suggesting the importance of variability in soil, microclimate (e.g., PAR and rainfall), and other socio-economic factors. We expect 1) increases in available N from legume inclusion and 2) improvement in soil quality and structure from organic matter accumulation under reduced tillage; although CAPS may take several years to have direct benefits on production. Further, we expect that CAPS will work indirectly through increased household wealth (via diversification of marketable crops) leading to more livestock and compost for soil amendment. For sustainability, these practices should be paired with agroforestry to improve access to fodder, reduce erosion, and reinforce traditional linkages of communities to forest resources.