Intercropping of maize, millet, mustard, wheat and ginger increased land productivity and potential economic returns for smallholder terrace farmers in Nepal

•A menu of legume intercrop options for subsistence farmers in Nepal was tested.•Maize + cowpea, millet + soybean, wheat + pea, mustard + pea, and ginger + maize – soybean appeared to be productive.•Seasonal intercropping increased yield by 16–30% and potential income by 15–288%.•Ginger + maize – soybean was an innovative year-round option in the mid-hills.•Intercropping appeared to be a viable option to intensify terrace agriculture.