Effect of deferred grazing during summer on white clover content of Waikato dairy pastures, New Zealand

Abstract New Zealand dairy pastures rotationally grazed at intervals of 25 to 30 days to low residual herbage masses (<1400 kg DM ha −1 ) over summer often suffer white clover death. An experiment was conducted over 1994–1997 in mixed perennial ryegrass/white clover dairy pastures to examine the effects of deferred grazing, the practice of holding over pasture in situ for 50, 75, or 100 days over summer, on white clover growth compared with a more common 25‐day grazing interval. Additional pasture cover built up in 100‐day deferred (100D) plots resulted in significantly ( P < 0.05) lower soil temperatures and higher soil moisture levels than in the 25D treatment. Clover stolon survival was up to 63% higher in deferred pastures than the 25D treatment. This, combined with higher clover seedling density, resulted in significantly (P< 0.05) higher clover contents in pastures following deferral compared with the 25D grazed pasture. These differences did not persist through to the following spring. Deferred grazing also resulted in small increases in total herbage accumulation but had little effect on ryegrass tiller density.