Blue grass alluvial plain pastures in the Kimberley

Page last updated: Thursday, 28 June 2018 - 11:48am

There are many different pasture types in the pastoral rangelands in the Kimberley region of Western Australia. The Department of Primary Industries and Regional Development (DPIRD) provides this pasture information to be used as a reference for assessing pasture condition, and as a guide for pastoral station staff and others interested in the productivity and maintenance of the pastoral rangelands.

Assessments can be used to monitor the success of management and to set goals for improving rangeland condition.

Blue grass alluvial plain pastures

These pastures are part of the Kimberley 'black' soils group of pastures, and the perennial bundle-bundle and ribbon grasses are the identifier grasses. Use the interactive key to pasture condition to help identify pasture type.

Pastoral value

Blue grass pastures in good condition are highly productive and can be used with lower quality feeds to provide year-round grazing. DPIRD recommends wet-season and post-fire spelling. Overstocking may cause soil erosion which will have long-term and significant adverse impacts on pasture condition and pastoral productivity.

Occurrence

Blue grass pastures occur on areas of black soil plains in the higher rainfall areas of the Kimberley. They are found on some of the floodplains of major rivers and in isolated pockets of black soil in basalt country of volcanic origin in the north Kimberley.

Back to top

Pasture condition

Good: In good condition, blue grass pastures are dominated by bundle-bundle or co-dominated with ribbon grass or perennial sorghum (on basalt). Other grasses may include native millet and feathertop, and black speargrass is likely to be present on basalt. There is very little bare ground visible, unless the pasture is heavily grazed, and the plants appear vigorous.

Photograph of blue grass alluvial plain pasture in good condition
Figure 1 Blue grass alluvial plain pasture in good condition in the Kimberley (photograph taken April 2010). A The area is dominated by dense, vigorous clumps of bundle-bundle; no undesirable species are obvious; there is almost complete soil cover.

Back to top

Fair: Prolonged heavy grazing reduces the density of desirable species. Intermediate species are more prominent and may make up one-third or more of the stand. The lower density and smaller size of desirable plants allows undesirable species, such as feathertop, to increase. Shrubs, such as prickle bush, may also increase. Some bare ground will be evident and loss of soil may occur on basalt country.

Photograph of blue grass alluvial plain pasture in fair condition
Figure 2 Blue grass alluvial plain pasture in fair condition in the Kimberley (photograph taken April 2010). A The density of desirable grasses, such as bundle-bundle, has decreased. B The undesirable perennial, feathertop, makes up a significant proportion of the pasture; soil cover is becoming patchy.

Poor: Blue grass pastures in poor condition have few desirable species. Bare ground will be obvious, and erosion may be evident. Undesirable species, such as feathertop, may become a significant part of the stand.

Photograph of blue grass alluvial plain pasture in poor condition
Figure 3 Blue grass alluvial plain pasture in poor condition in the Kimberley (photograph taken July 2009). A Desirable grasses, such as bundle-bundle, are widely spaced and lack vigour. B Bare ground is common, with some large patches. C Annual grasses and forbs are patchy and lack vigour.

Back to top

Associated plants

Plants associated with blue grass alluvial plain pastures in the Kimberley

Common name

(link to DPIRD species page)

Scientific name

(link to FloraBase)

Life form
Desirable species    

Bundle-bundle

Dichanthium fecundum

perennial

Ribbon grass

Chrysopogon fallax

perennial

Plume sorghum

Sorghum plumosum

perennial

Native millet

Panicum decompositum

perennial

Intermediate species    

Silky browntop

Eulalia aurea

perennial

Pan Wanderrie grass

Eriachne glauca

perennial

Wire grass, Northern Wanderrie grass

Eriachne obtusa

perennial

Black speargrass

Heteropogon contortus

perennial

White grass

Sehima nervosum

perennial

Flemings bush

Flemingia parviflora

annual

Undesirable species    

Feathertop wiregrass

Aristida latifolia

perennial

Prickle bush, mimosa bush

Vachellia farnesiana

perennial

Contact information

Matthew Fletcher
+61 (0)8 9166 4019
Kathryn Ryan
+61 (0)8 9166 4015