Effects of sheep grazing management on cocksfoot herbage mass and persistence in temperate environments

Abstract

Cocksfoot (Dactylis glomerata L.) is among the most important perennial grass species sown in temperate Australia. Newly sown cocksfoot pastures were established on 5 commercial farms (sites), in the temperate high-rainfall (>600 mm annual rainfall) zone of eastern Australia. Experiments were located on these commercial farms, and were measured from September 1993 to August 1996, to compare the effect of seasonal sheep grazing management strategies with continuous grazing (control treatment) on cocksfoot herbage mass and plant frequencies. Each experiment had 8 common grazing treatments and up to 5 local treatments, with 2 replicates and 2 years of start for treatments.

Cocksfoot herbage mass under continuous grazing declined at 2 sites, remained stable at 2 sites and increased at 1 site. No single grazing strategy had a significant linear (time) effect on cocksfoot herbage mass across sites and at the completion of monitoring in 1996 there were few treatments with a significant increase in fitted values for cocksfoot herbage mass compared to the continuously grazed control.

Under moderate grazing pressure (8–10 dry sheep equivalents) cocksfoot pastures appeared to be relatively stable and unresponsive to grazing management and therefore continuous grazing seems to be appropriate. High grazing pressure in summer (herbage mass below 1000 kg/ha) can reduce cocksfoot persistence and in drought stock should be removed from cocksfoot pastures. Summer seasonal closure increased cocksfoot frequency at all sites, except Four Mile Creek and Dundee. These studies have shown it is possible to improve cocksfoot herbage mass through the implementation of strategic grazing practices, particularly over summer and early autumn.