Fig. 2. Mean soil phosphorus content. Shown from urban (n = 8) and nonurban (n = 5) sites are: (a) mean water-soluble P content, (b) mean acid-soluble phosphorus content, (c) mean base-soluble P content, and (d) mean total P content. Dots indicate range of variation; whiskers indicate 5th and 95th percentiles; solid lines indicate median values; and dashed lines indicate means. Median values between urban and nonurban samples were significantly different in (a) water-soluble P contents and in (b) acid-soluble P contents for both the A and B horizons (p < 0.05).