While prairie and grazing brome grasses are more similar than they are different, there are some key differences between species and varieties. Prairie grasses have a higher yield potential than grazing bromes, but do need higher fertility and more rainfall or irrigation. Grazing bromes, while lacking in the top end yield potential, will tolerate lower fertility soils and persist in zones with lower annual rainfall and tolerate set stocking better than prairie grass. Table 2 summarises some of the main differences already mentioned to some key prairie and brome grass varieties.
Table 2: Characteristics of key prairie and brome grass varieties.
|Variety||Min. Rainfall (mm)||Sowing rate (mixes)||Sowing rate (straight)||Comments|
|Atom prairie grass||850+ or irrigation||5-30kg/ha||30-50kg/ha||Tiller dense, Year round production, Well drained soils, Rotational grazing preferred|
|Gala grazing brome||600+||5-20kg/ha||25kg/ha||Winter active, slightly acidic well drained soils|
|Exceltas coloured brome||650+||5-20kg/ha||25kg/ha||Less winter activity, slightly acidic well drained soils|
There is some variation in the sowing rates of both species in mixes listed in Table 2. The actual amount of prairie or brome grass needed in a specific pasture mix will vary depending upon a number of important factors, including:
In general, rates of 5–10 kg of prairie or brome grass is adequate for mixes that contain other grass species such as cocksfoot, ryegrass or tall fescue. Higher rates are used where prairie or brome are the sole grass in a mix, combined with clovers and herbs. For specific recommendations on what rate to use talk to your local agronomist, AusWest Seeds or Stephen Pasture Seeds representative.
Agricom; Agrinote; Ceres Atom Prairie Grass; www.agricom.com.au
Hackney B, Harris C, Dear B; (2007); Perennial brome grasses, NSW DPI Primefacts. Primefact No. 383
Prairie grasses have a wide leaf which is high quality and palatable to all grazing livestock. Brome grasses have a somewhat narrower leaf, but still of high quality and stock acceptance. Both plants have an erect growth habit making them friendly to companion species such as legumes, herbs and other grasses. They produce high quality feed that is comparable to ryegrass, but with greater heat tolerance. Unlike most grass species, feed quality is maintained when the plants go reproductive during spring / summer. In pasture mixes prairie grasses and bromes improve the amount and quality of feed on offer during periods when other species are reproductive and/or struggling with heat. Outside of the tropics and sub-tropical areas, prairie grasses and bromes do lack the winter growth of ryegrass, but respond well to gibberellic acid. Winter growth can be enhanced to give similar winter yields to ryegrass under favourable conditions with the use of gibberellic acid and nitrogen fertiliser. Table 1 shows the relative drymatter production of common prairie and brome grass varieties relative to a common perennial ryegrass. Across all three sites in this study the prairie grasses were close to or better than the yield of the perennial ryegrass. The grazing bromes were a little more varied, without the top end yield of the prairie grasses.
|Average annual rainfall (mm)||600||620||750|
|Exchangeable aluminium (%)||5||5||25|
|Variety||Herbage Production (t/ha)|
|Kangaroo Valley (Perennial ryegrass)||5.5||3.8||9.3|