Central Queensland cattle producers Sam and Laurice Morris are trialling legumes on their Baralaba cattle operation in a bid to curb the growing problem of buffel grass rundown, as this case study from Meat and Livestock Australia's explains…

The problem of buffel grass rundown has crept up on Sam and Laurice Morris. It has slashed their property's carrying capacity by up to 30pc in the past 15 years.

Buffel grass covers about 80pc of their property. They first noticed its declining productivity in the early 1990s with the appearance of reddening on leaf tissue, mainly in the Gayndah and US cultivars.

Small areas of buffel grass started dying across paddocks over several years. Initially, weeds dominated these areas, but over time, other palatable grasses have re-established.

Sam said that buffel grass deterioration had accelerated in the past decade, six years of which had received below-average rainfall.

Sam and Laurice operate a beef cattle breeding and fattening enterprise based on Droughtmaster and Charolais-cross composites. Steers are sold at about 300kg over the hook and cull heifers are sold at about 260kg dressed weight.

They have cut livestock to 500-600 head on the back of reduced carrying capacity. Sam estimated the property's carrying capacity had dropped 30% since the early 1990s, when buffel production and soil fertility were at their peak.

Trialling legumes

In an attempt to boost soil fertility, Sam considered using legumes. In 1996, he trialled 10ha of buffel mixed with Caatinga stylos (Primar and Unica cultivars) and sowed a small area of desmanthus. A 10ha plot of buffel grass was monitored to compare with the legumes.

The trial assessed the ability of the legumes to establish, persist, increase soil fertility and lift animal production in an environment of unreliable rainfall.

In the first five years, Sam said the legume pasture was visibly better than the buffel. The stylos and desmanthus produce, thick, thigh-high green pasture compared to the patchy, ankle-high buffel in the control plot.

Soil test results indicate that soil nitrogen levels in the legume and buffel plots are similar, and organic carbon levels are only marginally higher in the legume plot.

Sam said his gut feeling was that the legumes were improving soil fertility, and that looking at individual soil samples would probably better illustrate this, rather than the current practise of mixing soil samples from across the whole plot.

He said he believed more widespread planting of legumes on his property would enable him to run more cattle per hectare, and he hoped to collect grazing production data from the legume plot in coming years.

Sam said his next step might be to establish strips of legumes in paddocks to use in conjunction with mechanical renovation of buffel in the inter-rows.

Source: Meat and Livestock Australia