The use of frequency estimates in studying sward structure

Estimates of the frequency of absence of rooted perennial ryegrass tiller bases from concentric sampling quadrats of different sizes are recommended for characterizing the open space structure of perennial ryegrass swards. It is proposed that these estimates are useful for evaluating the persistence of grass species and cultivars in swards. Data on this aspect of sward structure could provide criteria for the productivity of a sward and thus for the need to reseed grassland.