Fig. 3: Yield, nitrogen (N) input and N balance across 32 rice cropping systems.

Panels show average rice yield (expressed as percentage of yield potential) versus A total N input (from fertilizer, manure, and fixation), B N balance calculated as N input minus N removal, and C yield-scaled N balance. Symbol type and color are used to distinguish tropical versus non-tropical regions (circles and squares, respectively) and irrigated versus rainfed systems (blue and yellow, respectively). Pearson’s correlation coefficient (r) is shown only when the association between variables is significant (two-tailed Student’s t-test; p < 0.01; n = 32 cropping systems). Cropping system codes are shown in the caption to Fig. 1. Data are provided in Source Data.