The effects of grazing on components of grain yield in winter barley

Abstract

A paddock-scale experiment was conducted over two seasons to determine whether winter barley will fit adequately into a farming system that requires both feed and grain, and to investigatehow grazing affects the grain yieldcomponents. The 6-row 'Illia' and 2-row 'Priver' cultivars produced 1.3-2 tlha of DM by mid August when sown in April. Grazing to ground level in August reduced grain yields by about 10%, by reducing the ear population, despite the fact that mainstem apices were below soil level at thetime of grazing. Combine harvested grain yields ranged from 2.3 to 3.6 tlha in seasons with below average rainfall.

Effects of grazing on grain yield of winter barley and triticale: The position of the apical dome relative to the soil surface

“…In practice thermal time can be influenced by sowing time and grazing time. Although there are no comparable data for triticale, Scott et al (1988) r~orded herbage production of 1720-2160 kg DM/ ha from 'Illia' barley by mid August, similar to the 1740 kg/ha recorded here. These yields were all recorded in seasons with above average winter temperatures (Table 1) but in the previous experiments the plots were grazed on 5 and 17 August, at least 10 days earlier than in the present experiment It seems likely that herbage yields of 'Illia' in the present experiment could have been increased to over 2000 kg DM/ha by sowing earlier than 28 April.…”

“…Both barley and triticale produced similar grain yields and although triticale produced a higher herbage yield at grazing, animal in takes were simi lar confirming the high palatability of 'Illia' winter barley (Scott 1984;Scott et al 1988). A third possible use for these species could be silage production in mid spring (Anon.…”

“…Differential responses to grazing may be related to soil type as on shallow stony soils both Martin & Knight (1987) and Scott et al (1988) reported yield reductions of about 10% when Aprilsown "Illia" was grazed at about the 6-8 leaf stage. On more moisture-retentive soils there was no grain yield reduction when • Illia' barley was grazed (Scott 1984), a result similar to that reported here.…”

“…These yields were all recorded in seasons with above average winter temperatures (Table 1) but in the previous experiments the plots were grazed on 5 and 17 August, at least 10 days earlier than in the present experiment It seems likely that herbage yields of 'Illia' in the present experiment could have been increased to over 2000 kg DM/ha by sowing earlier than 28 April. Unusually dry conditions in April delayed sowing time beyond the normally recommended mid-April period (Scott 1984;Scott et al 1988). This sowing time is a compromise between the need to sow early to accumulate thermal time and the likelihood of the crop becoming severely infected with the aphid transmitted Barley Yellow Dwarf Virus (BYDV) when sown in early April (Smith & Allen 1962).…”

“…Even though cereals grown for grain production are not commonly grazed in New Zealand now, early sowing in autumn offers the opportunity to graze (Gallagher et al 1983) although the effects on grain yield are variable (Scott 1984;Martin & Knight 1987;Scott et al 1988).…”