Fig. 1: Nutrient addition effects on leaf litterfall in Budongo Forest Reserve, Uganda. | Nature Geoscience

Fig. 1: Nutrient addition effects on leaf litterfall in Budongo Forest Reserve, Uganda.

From: Response of tropical forest productivity to seasonal drought mediated by potassium and phosphorus availability

Fig. 1

a–f, Box plots (25th quartile, median and 75th quartile) and whiskers (1.5 × interquartile range) of annual leaf litter production (a–c; n = 16 plots) and cumulative leaf litterfall (d–f, mean ± standard error of the mean (SEM); n = 16 plots) measured bi-weekly from May 2018 to April 2021, pooled for plots with or without nitrogen (+N vs −N; a,d), phosphorus (+P vs −P; b,e) and potassium (+K vs −K; c,f). b–c and e–f show the reduction effects of P addition in the first year and of K addition in the three-year experimental period on leaf litterfall. The y-axis breaks in panels a–c represent the omitted range (1–5) of a continuous scale to improve the visualization of data points. Statistical analysis was based on a full factorial N–P–K experiment. Treatments +N (N, NP, NK, NPK) and −N (control, P, K, PK) are pooled in a and d. b,c,e,f follow a similar pooled approach. Grey shades represent the dry season (≤100 mm rainfall per month) whereas the vertical dashed lines indicate dates of fertilization.

Back to article page