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Grazing in the Gulf Country

Overview

The Gulf region is the largest in the tropical savannas, covering an area of approximately 425,000 square kilometres. It encompasses a great variety of environments, from the rocky uplands around Mount Isa to the rich bluegrass flats which extend from the most southerly point of the Gulf. Rainfall in the region generally decreases from north to south and east to west. There is also great variation in the growing season, from 20 weeks of the year at Normanton to only nine near Cloncurry. It straddles Queensland and the Northern Territory where the historical development of the pastoral industry has differed; evident in the disparity of lease sizes. On the Northern Territory side, property sizes are significantly larger. This is in part due to historical factors but lack of subsequent subdivision in the Northern Territory probably also reflects the poorer fertility of the country.

 

Brahman cattle like these make up the majority of the herd in the Gulf district

Variable grazing country

The gulf region is not unique in its poor fertility and very low carrying capacity and in many ways has a lot in common with less fertile areas of the Cape York and Kimberley regions. There are a great variety of soil types in the region and as a result the quality of the grazing country is highly variable throughout. Good country tends to be used for fattening while poorer areas are utilized for breeding. On the whole though this region is considered fairly poor grazing country and stocking rates are therefore maintained at a low level. Significant areas of the region suffer from floods in the wet season.

There are about 200 stations in the region, including both corporate and family run enterprises. The smallest properties in the region are to be found to the south west of Croydon, although this may be more related to historical rather than biophysical factors. As is the case throughout the tropical savannas, corporately owned properties tend to be larger.

Markets

While breeding is an important earner for producers in the Gulf region, supplying cattle to the live export trade has been growing in significance, with the proportion of properties participating more than doubling between 1996 and 1997 (ABARE 1998). The port of Karumba is used by the majority, and more than 50,000 head were exported in 1996. Producers on the Northern Territory side of the border tend to export live cattle out of Darwin. Numbers of live cattle exported from the Gulf region are expected to rise and this has important implications for herd management in the region. However the turn off of cattle to domestic store markets, or to affiliated properties for corporately owned enterprises, will continue to be a major earner for producers in the Gulf region.

Land systems

Some of the most productive and resilient grazing country in the Gulf region can be found at the base of the Gulf, following the major rivers that empty at that point: the Norman, Alexandra, Leichardt, Nicholson and Flinders. This area consists of floodplains with alluvial cracking clay soils. The relatively good soil fertility results from run-on water, sediments and nutrients, and supports areas of Flinders (Iseilema spp.) and Mitchell (Astrebla spp.) grass. To the east there are broad sandy plains supporting a vegetation of low paperbark and wattle woodlands and areas of stringybark and bloodwood. The south east inland sector of the region has similar tree cover but also has many top feed species such as whitewood, bean tree and vine tree. This explains the slightly higher stocking rates in the area.

The region between Camooweal and Cloncurry, known as the Mount Isa highlands, consists of rugged stony hills and mountains. The vegetation includes low trees of snappy gum, box wood and blood wood, and the dominant pasture species is spinifex (Triodia spp.). The area has very low fertility, in particular extremely low available phosphorous, and one of the most conservative stocking rates in the region. South of Cloncurry is arid, short grass country, again mostly spinifex growing on infertile stony soils.

South of the Mitchell River

The richest grazing country in this part of the Gulf region is on the frontages of the Mitchell and Gilbert rivers and floodplains. Marine plains that are dominated by marine couches, with wild rice and watergrasses around the lagoons also provide better grazing areas. Fire is used in this part of the Gulf as a mustering tool to encourage cattle to areas of green pick, to spread cattle to lighter country and to prevent late dry season fires. Rubber vine (Cryptostegia grandiflora) is becoming a major concern, along with stinking passion flower (Passiflora foetida). As a result of their proximity to port of Karumba, producers in this region compared to those further north stand to benefit significantly from the live export market.