An evaluation of lucerne for persistence under grazing in New Zealand

B.M. Harvey, K.H. Widdup, B.A. Barrett - Proceedings of the New Zealand Grassland Association 76, pages 111-116

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

New Zealand and Australia show similar climates due to close proximity so this study on lucerne for persistence under grazing conditions will be useful for Australian farmers.

What is the problem?

The on-farm use of lucerne (Medicago sativa) for grazing and conserved feed has increased in New Zealand over recent years, with new cultivars coming onto the market, including more winter-active ones. The extent to which the winter active types contribute to annual feed production, and the relationship to critical traits like persistence, has not been systematically tested.Trials were used to evaluate a range of lucerne cultivars and elite experimental populations.

What did the research involve?

Two concurrent trials over a 4-year period were done ranging in dormancy from 2 to 10 under a contrasting grazing regimes near Lincoln, New Zealand.

What were the key findings?

More winter-active cultivars in the higher fall dormancy (FD) classes had similar growth to lower FD classes in all seasons except autumn, where they exhibited 18% greater yield than the lowest FD entry. However, these higher FD populations do not persist as well under heavy grazing, with a reduction in ground cover of up to 90% after four years, compared with only a 25% loss in lower FD classes. There was a negative correlation between FD and persistence measured as plant survival over 4 years (R2=0.73). However, one high FD entry showed increased survival under grazing, suggesting there is scope for selection of types with improved cool season growth and grazing tolerance. The concurrent lucerne trial subjected to a low-frequency grazing/ cutting regime showed faster recovery from defoliation than the adjacent hard grazed regime, suggesting stored underground reserves were more available for regrowth.

Final Comment

The researchers concluded that lucerne cultivars with FD ratings in the 3 to 5 range are most suitable for yield and persistence under grazing in these conditions. There is also scope for breeding to improve plant survival and dry matter yield within FD class.

2014 - New Zealand - B.M. Harvey, K.H. Widdup, B.A. Barrett - Proceedings of the New Zealand Grassland Association 76, pages 111-116
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