Perennial pastures for animal production in the high rainfall areas of Western Australia

Summary

The aim of this project was to generate a better understanding of the costs of establishment, economic benefits, suitability and sustainability of perennial grass based pastures in the high rainfall areas when grazed by sheep and cattle. Perennial grasses are well suited to the high rainfall, long growing season, southern regions of Western Australia. Such pastures can provide benefits to the farming industry through:

improved per hectare returns by providing superior summer/autumn feed supply and so reducing supplementary feed costs and improving the pattern of carcase turnoff.

increased water usage and reduced soil erosion.

The use of perennials has not been extensive and a better understanding of the lack of producer confidence in their use is important if the value of these pastures is to be exploited.

This project commenced in 1992 and was cornpleted in December 1996. It has been conducted on 23 farm locations spread across the >600 mm rainfall areas of the south and west coasts of WA and has incorporated 3 types of activity.

On-farm monitoring sites where animal and pasture performance was assessed on an existing perennial pasture.
On-farm demonstration sites where we established a perennial pasture as part of the project and cornpared it with an adjoining annual sward.
Three grazing experiments incorporating different perennial pasture species, grazed by either sheep or cattle The perennial grasses examined were basically cocksfoot, phalaris, tall fescue, perennial ryegrass and Kikuyu grass.
Amidst many problems associated with long term grazing work on farms, changing agriculture plus 3 very dry summers, the main outcomes have been:

With satisfactory control of annual weeds (nb grasses) and insects (nb RLEM) temperate perennial grasses can be established in atumn and Kikuyu grass in spring.

Perennial grasses increased $/ha returns in 75% of comparisons with annuals when grazed by catlie

Persistence of perennial grasses is harder to achieve when they are grazed by sheep rather than by cattle. On farm stands of temperate grasses all declined severely when grazed by sheep, but not the sub-tropical kikuyu grass.

Well established perennial grasses complernent subterranean clover, limiting the invasion of broadleaf weeds (egCapeweed).

The number of ternperate perennial plants in the first year is the highest that will exist in that sward.
The rnain costs when establishing perennial pastures is seed ($30 to $50/ha) and the grazing foregone in the year of establishrnent (up to 60% of grazing days).

Estimated number of years to break even when establishing perennial pastures ranges from 2 to > 10 years depending oncirumstances.

The value of perennials should be looked at in a whole farm context'especially in cropping areas and on the sandplain

The benefits of Kikuyu grass on the south coast is its tolerance to heavy grazing while reducing erosion risks on fragile soils.

Data from many of the sites have been used by Dr A Moore and Dr J R Donnelly of CSIRO to help validate GRASSGRO. All producers in the high rainfall areas of the south and west coasts of Western Australia have been notified of the work and the basic outcomes. At the same time they were offered a free copy of the booklet we have prepared as a result of this project "Perennial Grasses for animal Production in the High Rainfall Areas of WA", if they request it. This bulletin outlines the Cost analysis of establishing and growing perennial grasses as well as establishment techniques, rnanagement strategies and suitable species for different locations. This will assist farmers that are contemplating establishing perennial grasses as well as those seeking more information on managing existing stands. Cattle farmers can benefit from the' use of perennial pastures immediately if they are contemplating renovating a deteriorated pasture.

In this case it is likely to take 3 to 4 years to cover establishment costs whether they sow a perennial pasture or resow an annual pasture. However if a good annual pasture is to be replaced it would take at least 6 years to pay back establishment costs from the benefits of the perennial stand. Producers have to be convinced of the persistence of perennial grasses. Kikuyu ~rass is likely to be the species of perennial most likely to benefit the sheep industry, in terms of the fibre strength of the wool and better control of soil erosion, especially on the south coast sand plane. Kikuyu pastures can be grazed more heavily than annual pastures with a reduced risk of wind erosion. The break even period when establishing kikuyu grass is similar to that for temperate grasses outlined above. At the four demonstration sites where we established temperate perennials grasses while grazing with sheep, the perennial grasses did not persist.

This effect was exacerbated by the 3 very dry years with associated late starts to the growing seasons. The depressed state of the animal industries in recent years together with 3 very dry years on the south coast of WA has stretched the resources of many producers who traditionally rely on grazing enterprises. The rapidly increasing woodchip industry is targeting these high rainfall areas with the planting of bluegums in direct competition with the grazing industries. Initial work with kikuyu grass in this project has stimulated interest in its value for using ground water outside the normal growing season. Projects are now under way in the Sustainable Grazing Systems Program to investigate further the effects of increased water use by kikuyu in water recharge areas, both in the presence and absence of trees.