Annual mowing, a main management strategy of grasslands, would reduce primary productivity, though might increase plant diversity. Nitrogen (N) fertilization is widely used to raise productivity in global pastures, but always results in biodiversity losses. It is thus a challenge to balance the divergent impacts of mowing and N fertilization on biodiversity and productivity. Here, we examine 9-year responses of aboveground net primary productivity (ANPP) and species richness to mowing across a N addition gradient (0, 2, 5, 10, 20, and 50 g N m