In Southern Hemisphere seed production, crops often are grazed in winter and early spring. Closing date is the date of last grazing or defoliation in spring, before the crop is allowed to enter reproductive development. There are no data on the impact of grazing on first-year seed crops. Generally it is recommended that first-year seed crops should not be grazed during the establishment period to ensure that tiller production will not be compromised. However, in the North Island of New Zealand, where mild autumn and winter conditions result in early spring growth, March-sown tall fescue seed crops commonly are grazed during their first winter.

After harvest, regrowth of forage tall fescue is rapid, especially if soil moisture and N are not limiting, and this regrowth can provide excellent forage. Since the quality of tall fescue deteriorates rapidly as the plant approaches maturity (see Chapter 6, Chapter 7, and Chapter 11), it requires a strategy of frequent defoliation to maintain forage quality.

The effects of closing dates ranging from fall (March) to late spring (October) were examined in six tall fescue trials between 1982 and 1985 at Lincoln and Palmerston North in New Zealand (Brown et al., 1988). Seed yields from crops closed at the end of spring were significantly lower (270 kg/ha) than those for crops closed earlier (400 kg/ha). The authors concluded that Roa tall fescue can be closed any time between spring and mid winter.

Trials simulating closing dates in forage and turf tall fescues (Rolston and Archie, 2001, 2002) suggested that in general tall fescue crops need to be closed by the end of August in New Zealand, but there is variation among cultivars. Rolston and Archie (2002) commented that the height of the apical meristems at final grazing may be critical, and that crops grazed frequently through winter have meristems at a lower elevation and are more tolerant of later grazing in the spring.


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