The Loess Plateau in northwestern China constitutes one of the most vulnerable semi-arid regions in the world due to long-term decline in forest cover, soil nutrient depletion by agricultural use, and attendant soil erosion. Here, we characterize the significance of N 2 -fixing Robinia pseudoacacia L. and non-N 2 -fixing Juglans regia L. for improving nutrient availability and water retention in soil by comparing a range of biological and physicochemical features in monoculture and mixed plantations of both species. We found that N 2 -fixing Robinia facilitates the nitrogen and phosphorus composition of non-N 2 -fixing Juglans in the mixed stand as a consequence of improved soil nutrient availability, evident as higher levels of nitrogen and labile carbon compared to mono-specific stands. This demonstrates that intercropping N 2 -fixing Robinia with non-N 2 -fixing woody plants can greatly improve soil carbon and nitrogen bioavailability as well as whole-plant nutrition and can potentially mediate water retention with additional sequestration of soil organic carbon in the range of 1 t C ha−1 year−1. Thus, intercropping N 2 -fixing woody species (e.g. Robinia pseudoacacia or Hippophae rhamnoides L.) with locally important non-N 2 -fixing tree and shrub species should be considered in afforestation strategies for landscape restoration. Unlabelled Image • Intercropping of N 2 -fixing Robinia with non-N 2 -fixing Juglans improved soil N and labile C availability of the mixed stand • Intercropping with N 2 -fixing Robinia improved plant nutrition and water status of non-N 2 -fixing Juglans • Intercropping with N 2 -fixing Robinia mediated additional SOC sequestration compared to Robinia and Juglans monocultures • Intercropping of Robinia with Juglans seems a feasible afforestation strategy for landscape restoration [ABSTRACT FROM AUTHOR]