Overview
Our two experiments both measured aboveground plant biomass at regular intervals during the growing season at a relatively uncommon level of temporal detail. From these measurements we could calculate daily RGR per species throughout the growing season, which provides unique insight into growth rates and their temporal changes (in contrast, most studies lack a temporal dimension and measure biomass only at harvest). We used these measures of RGR to identify when, during the growing season, differences in RGR best predict competitive outcomes in mixtures, comparing the high and low fertility treatments in each study. The first data set comes from a competition experiment with five European perennial grass species grown under nutrient-limited unproductive and nutrient-rich productive conditions in the experimental garden of the University of Zurich, Switzerland (47° 23’ N, 8° 33’ E, and 546 m height a.s.l.). The second data set lacks independent monocultures but comes from a field experiment in which nitrogen and phosphorus are added alone or in combination to a flat alpine meadow at the Alpine Meadow and Wetland Ecosystems Research Station of Lanzhou University (Azi Branch Station) in the eastern Tibetan Plateau (33°40’N, 101°51’E, altitude 3500 m a.s.l.), Gansu, China. The growing season typically starts around April 15 (~ day 106) in Zürich and around May 15 (~ day 136) in Gansu.