The effect of the amount and frequency of precipitation on plant performance.

The effects of precipitation amount and frequency on plant performance. For each of the fourteen species (4 monocots and 10 eudicots) we consider how plant height, above-ground biomass, below-ground biomass and the ratio of above:below-ground biomass are affected by precipitation amount (70 vs 90 mm), precipitation frequency (3, 15 or 30 days), and the amount × frequency interaction. Linear mixed-effects models were used in all analyses and we report the numerator degrees of freedom (ndf), the denominator degrees of freedom (ddf), F-values, and P-values for all effects. A significant relationship (P