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Fig. 3 | BMC Biology

Fig. 3

From: Stomatal conductance limited the CO2 response of grassland in the last century

Fig. 3

Long-term changes in physiological parameters at the Park Grass Experiment. Intrinsic water-use efficiency-change (Wi-change) (a), hay yield-change (b), δ18Ocellulose-change (c), and nitrogen acquisition-change (d) during the last century. Changes were calculated as the difference between period 2 (2004–2018) and period 1 (1917–1931). Results are presented for each fertilizer treatment (in the order of the treatment effect on the long-term δ18Ocellulose-change), the mean of all dicot-rich and grass-rich treatments, and all treatments combined. Bar plots and error bars represent the calculated difference ± SE (SE calculated as SE from period 1 + SE from period 2; n = 11–15 in each period for each treatment depending on data availability; see Additional file 1: Table S1 for details). t tests were used for determining if the long-term changes were statistically significant and significance is presented when P < 0.05. Significance levels: *P < 0.05; **P < 0.01; ***P < 0.001. Significant differences between grass-rich and dicot-rich treatments are designated with different capital letters

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