Figure 4. Effects of plant species richness and soil diversity on soil pools and processes . Relationship between soil functions and plant species richness were explored in each soil diversity levels at early flowering stage (pre-drought) (i), during drought (ii), and after recovery (iii). The relationship between observed plant richness and (a) ammonium, (b) nitrate, (c) phosphate, (d) rate of N mineralization, and (e) acid phosphatase activity. Significant plant richness effects were shown with regression lines.