Long-term Piliostigma reticulatum intercropping in the Sahel: Crop productivity, carbon sequestration, nutrient cycling, and soil quality

•Without fertilizer, millet yield was 105% greater with shrubs from 2011 to 2015.•Increases in rainfall water use efficiency (WUE) crop yield (kgmm−1) with shrubs.•Decreases in rainfall WUE crop yields without shrubs.•Differences in temporal water use by crops and shrubs explain lack of competition.•P. reticulatum significantly enhanced soil quality: both carbon and nutrients.