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

New Zealand dairy pastures rotationally grazed at intervals of 25 to 30 day s to low residual herbage masses (<1400 kg DM ha(-1)) over summer often suf fer white clover death. An experiment was conducted over 1994-1997 in mixed perennial ryegrass/white clover dairy pastures to examine the effects of d eferred grazing, the practice of holding over pasture in situ for 50, 75, o r 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 defer red (100D) plots resulted in significantly (P < 0.05) lower soil temperatur es and higher soil moisture levels than in the 25D treatment. Clover stolen survival was up to 63% higher in deferred pastures than the 25D treatment. This, combined with higher clover seedling density, resulted in significan tly (P < 0.05) higher clover contents in pastures following deferral compar ed with the 25D grazed pasture. These differences did not persist through t o the following spring. Deferred grazing also resulted in small increases i n total herbage accumulation but had little effect on ryegrass tiller densi ty.