Economic evaluation of Matua prairie grass as a pasture species on Canterbury sheep farms

Abstract

Matua prairie grass could play a significant role on Canterbury pastoral farms as a perennial greenfeed. It should not be seen as a substitute for ryegrass/white clover pastures or for lucerne stands but rather as a complement to both. In its role as a perennial greenfeed crop, however, it competes directly with annual forage crops, cereal greenfeeds and specialist ryegrass greenfeeds. Although Matua has good winter growth potential its susceptibility to trampling and bruising at this time means that it should not be grazed during winter. Its role in the provision of winter feed lies in the fact that by using Matua in autumn during flushing and mating, it is possible to spell ryegrass pastures, allowing them to accumulate dry matter for winter consumption. Dry matter produced by Matua swards in winter may be consumed in early spring during lambing, while late spring production can be carried forward in to the summer. The rapid response to autumn rain achieved by Matua makes it a more reliable source of feed during flushing and mating than the ryegrass/white clover system. Matua will not replace lucerne as a drought resistant plant in Canterbury conditions, but will respond to any application of moisture better than ryegrasses. Because Matua must be spelled between grazings until the plant has regrown to at least 15 centimetres high, and should not be grazed during winter it must be grown in conjunction with ryegrass-based pastures which contribute flexibility to the grazing system. Trials have been successfully conducted in which 50 per cent of the farm area is sown in Matua but local farm advisors believe that 30 per cent is a more suitable proportion. At that level the grazing system is sufficiently flexible to cope with Canterbury drought conditions and there is sufficient Matua to provide useful quantities of high quality greenfeed at critical periods of the year. On fertile soils a farming system with up to 50 per cent Matua-based pastures has been shown to be more profitable than a system based on ryegrass pastures only. There is also some evidence which suggests that a system incorporating Matua is economically superior on less fertile soils but this has yet to be proved.