Effects of Grazing Management on Grass Tiller Density Characteristics of Ryegrass-White Clover Dairy Pasture

The characteristics of pastures receiving different systems of grazing management during September-May were examined over 3 years from September 1989. Three farmlets (each 10 0.8-ha areas) represented (i) rotational grazing every 30 days (September-May) (RG), (ii) fast rotations during spring (September-November) (SFR) and (iii) fast rotations during spring, summer and autumn (September­May) (SSFR). Pastures were predominantly perennial ryegrass (Lolium perenne L.) and white clover (Trlfolium repens L.) grazed by dairy cows. Large increases in grass tiller density occurred in SFR and SSFR areas after the first year compared with the rotationally grazed pastures, which have been maintained throughout the experiment, Responses to SFR and SSFR were similar for most measured parameters. Perennial ryegrass made the greatest contribution to total tiller density (2000-4500 tillers/m2), Poa annua contributing I 500- 1700 tillers/m2 at September assessments. Overall grass tiller densities were low (maximum ca. 6000/m2). There were few consistent changes in pasture botanical composition over the trial.