Fig. 1. Growth rate of perennial ryegrass turf with daily N additions (top) or intermittent N additions (bottom). Note the different ranges of the x-axes. Arrows indicate intermittent N additions, with long, intermediate, and short arrows representing the 32-d, 16-d, and 8-d additions, respectively. Values are means of three replicates. For clarity, error bars are absent; standard deviation averaged 7%.