Fig. 2: Scale-dependent effects of land system on the risks of antibiotics in soil.
a–d Number of analyses (20 full-parameter analyses with different datasets: segments from the upper and lower limits of the same data were excluded) with significantly positive (+, red) or negative (−, blue) or nonsignificantly positive (+, light red) or negative (−, light blue) relationships with antibiotic pollution risks based on linear regressions. The two-sided p values estimated by the t-statistic are used to identify the statistical significance when their values are less than 0.05. Land use was measured by the area proportions of arable, built-up, and natural lands. Land management was measured by manure application rate and irrigated area. The average R2 values for 20 full-parameter analyses are presented. e–h Contributions of arable land use and management to soil antibiotic pollution risks; the columns and error bars indicate mean contribution and standard deviation (n = 20 subdatasets). The points on the columns show the data distribution. The plots from left to right are the results of watershed level 1, level 2, level 3, and level 4. Level 1 corresponds to large watersheds.
