Fig. 2: Yield benefit for each indicator crop from crop rotational diversity (CRD) and external nitrogen (N) fertilisation.

The y-axis presents model-predicted yield benefit compared to monocultures at year = 0, based on mean-centred observations, i.e., the difference from to the long-term within-site average across all CRD treatments for each indicator crop (a–c). Yield-benefit of 0 indicates model predictions remained the same, negative values are yield losses and positive values are yield benefits as yields in monocultures at year = 0. CRD is characterized by species diversity (based on the inverse Simpson’s diversity index; top row) and functional richness (the number of functional groups included in the rotation; bottom row), and external N fertilisation is classified as low or high (left and right panel in each pair). The curves (top row) and symbols (bottom row) represent model predictions after 5, 20, and 35 years since the beginning of the experiment (dotted green lines, dotted orange lines, and solid blue lines, respectively). We chose these three time periods to represent the early-, middle- and long-term effects of time within our range of data. The 95% CIs are indicated by the shaded areas surrounding the lines (top row) and error bars (bottom row).