Effect of growth stage at cutting on yield and quality of lucerne cultivars from different dormancy groups in northern Victoria

Abstract

At Kyabram, Victoria, the effects of growth stage at cutting on dry matter (DM) yield and quality of lucerne was determined during the warm season haymaking period for cultivars with contrasting winter dormancy characteristics. Growth stages at cutting were pre-flower bud, flower-bud, 10% bloom and full bloom. Cultivars were winter non-dormant CUF 101 and Pioneer Brand 572, semi-winter dormant Pioneer Brand 581 and winter dormant Pioneer Brand 545. Cultivar responses or interactions between cultivar and growth stage at cutting were not significant (P>0.05) for dry matter yield, crude protein or in vitro digestibility. Cutting of the pre-flower bud stage, compared with cutting at the 10% bloom stage, reduced DM yield by 18% (16.4 v. 13.5 t/ha), but increased crude protein content of the lucerne from 19.3 to 24%. The total protein yield per hectare was not affected by cutting stages from pre-flower bud stage to 10% bloom. Cutting lucerne at the flower bud stage rather than at 10% bloom gave increased protein content and digestibility with only a moderate yield decline. However, more frequent cutting was unsatisfactory as it decreased the density of the stand and increased the proportion of weeds and so could not be recommended.