Selection for grazing tolerance
No lucerne cultivar survives continuous, heavy grazing. Persistence is improved by spelling, although this does not necessarily mean a rigid rotational grazing system (see chapter 9). Winter-dormant cultivars with low crowns should survive grazing better than winter-active cultivars with more upright crowns. Wellmanaged stands of winter-active cultivars have, nevertheless, persisted well when grazed by cattle, and
perceived differences in grazing tolerance based on crown habit are not as important in cultivar selection for grazing.
Selection for disease resistance
Disease resistance is a very important factor in the selection of cultivars for grazing, and the requirements are identical to those for hay. There is less need for the highest level of resistance to colletotrichum crown rot in cultivars used in the semi-arid cropping and pastoral zone.
Selection for aphid resistance
The selection of aphid-resistant cultivars for grazing is still recommended, despite the less frequent occurrence of aphids in mixed pastures or grazing swards. It is impossible to control aphids economically using insecticides in large areas of lucerne in extensive grazing systems.
Selection for production of winter protein
Highly winter-active lucernes produce significantly more feed and, therefore, protein for winter grazing than semi-dormant cultivars in northern Australia. During winter, feed deficits are common.
Swards of winter-active cultivars with a high level of colletotrichum crown rot resistance are ideally suited to dairy cattle feeding systems employing strip grazing and a carefully planned spelling program to enhance persistence.
In extensive mixed pastures for beef cattle or sheep, winter-active cultivars are even more significant contributors to alleviating the winter-feed deficit. Grazing management in lucerne stands is usually not well controlled. Here, providing the pasture is initially lucerne-dominant, some decline in the lucerne component is acceptable. Planting both winter-active and semi-dormant cultivars in separate paddocks can provide the benefits of both dormancy categories. However, the use of only semi-dormant cultivars is no longer recommended for grazing. Their lower protein production in winter means that they provide less feed when it is most needed.
Choosing a cultivar for your needs
Table 2.1 in the article “Selecting the Right Lucerne” lists the cultivars available in Queensland in 2001. The cultivars are listed according to winteractivity level and each cultivar is given a rating for winter activity and resistance to the three lucerne aphids, the main root and crown diseases, and leaf diseases. Root disease susceptibility is rated and those with low resistance are only recommended for well-drained soils. From this table, the cultivar can be chosen
that best suits the farmer’s needs. If cultivars have similar characteristics, the choice comes down to either local experience or personal preference.
This list is updated regularly and is available in two DPlnotes:
Lucerne for Irrigated Hay and Dairy Production — Cultivar and Management Suggestions
Lucerne in Dryland Farming Systems — Cultivar and Management Suggestions
These are available from the DPI website www.dpi.q1d.gov.au and on DPI Prime Note CD-ROM, which can be
accessed at DPI Information and Client Service Centres throughout Queensland.
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