Sown in the 1970s and ‘80s, the Johnsons’ buffel grass pastures were becoming the limp lettuce left in the bottom of the bowl. Mike had found signs of pasture rundown and associated production losses from lower dry matter production and reduced carrying capacity. It was time for new and interesting choices.
Mike first established stands of leucaena around fifteen years ago, planting twin rows 7m apart on old cultivation country and 15m apart into pasture. He now has around 100ha planted. He said that establishing legumes required careful planning. Mike inoculates leucaena and desmanthus seed immediately prior to sowing, into carefully prepared land.
“To create the rows, I sprayed the native pasture out, deep ripped it with a Yeomans ripper and worked it with a 4m wide scarifier and harrows to prepare a fine seed bed,” he said.
“It’s important to get rid of all the buffel in the strips, because until it is established, the leucaena won’t compete with it. I spray Spinnaker* (imazethapyr) 3m wide down the rows to prevent early weed growth.”
Mike has noticed that leucaena is more productive on heavier clay soils with better water holding capacity, than on the lighter soils. Ongoing management is fairly intensive for legume-grass pastures, and Mike treats the leucaena like a crop.
The leucaena is planted across five small paddocks of 20–40ha, and steers are rotationally grazed on these pastures throughout the summer. At the end of the season, Mike runs a mob of cows and calves across the five paddocks to knock down the leucaena more effectively.
Amongst the leucaena, Mike has also had success with desmanthus.
“Every eight rows I planted desmanthus instead of leucaena – just to try it – using the leucaena planter,” Mike said. "It’s spreading fairly well through the paddock via shooting seeds and cattle."
“To fix nitrogen, the desmanthus requires the same rhizobia inoculant as leucaena, so it’s going to get the rhizobium from the leucaena if it spreads nearby.”
Although Mike has not measured the extent of the productivity increases, he has noticed a significant increase in steer carrying capacity on buffel grass pastures with leucaena plantings.
“The benefit is in the improved quality of pastures. Leucaena has a high crude protein content (up to 30% in the leaf) which allows the animals to use the grass more efficiently and gain weight faster as a result,” Mike said.
Case Study courtesy of MLA
*Spinnaker is a Nufarm registered herbicide
Location: Dulacca, QLD
Enterprise: Beef cattle, croppping
Producers: Mike and Judy, Dan and Petrina Johnson
Soil type: Heavy loams to dark cracking clays
Pasture type: 1,800ha buffel grass pastures, 100ha leucaena, with desmanthus strips, 200ha cultivation (oats, barley, forage sorghum), 300ha scrub forest country
Mixed greens are on the menu today for the cattle on Mike and Judy Johnson's Queensland property after it was discovered the earlier offerings were not hitting the mark.