Lupin gains traction in high country

 The plant is the lupin, the subject of many a tourist’s holiday snaps in the Mackenzie District for decades, but until recently confined to roadsides, riverbeds, and trial plots.

Now, largely thanks to the persistence of one particular scientist, the plant is starting to find a place on the lower country of a few of the extensive sheep and beef farms that manage the Mackenzie landscape.

One of them is Sawdon Station, where Gavin Loxton – better known locally as ‘Snow’ – sowed his first paddock with lupin ten years ago. Now, he has 300ha established and is sowing more every year, direct-drilling 2kg/ha into the sparse, erosion prone pasture.

“It’s costing us about $140/ha to develop this ground [with lupin] and then there’s electric fencing and stock water needed so you can make use of it, which maybe takes it to $250/ha.”

Depending on the seasons, within two or three years of sowing plants start shedding substantial amounts of seed which, in due course, perpetuates the stand, but the lupin never completely takes over and grasses, which struggled to survive previously, thrive in the micro-climate the bushy legume creates.

“The leaves keep the soil cool in summer and the residue insulates the ground in winter,” explains Loxton. “It’s the only place on the farm we ever find Italian ryegrass surviving long-term.”

Cocksfoot also benefits from neighbouring lupin, extra nitrogen fixed rendering the hardy grass much more palatable.

As for the lupin, sheep “go for the flowers first, then the leaves and generally leave the stalks,” explains Loxton.

He’s found little problem with palatability but is working with lupin guru David Scott (see sidebar) to find, and hopefully develop, a low alkaloid line.

Stock also benefit from lupin’s micro-climate and as the first plant out of the blocks in spring the clumps provide good cover for lambs. Several stations are now lambing Merinos among them, they point out.

In Loxton’s case, lambs on their mothers gained 160g/day on lupin last spring/summer, despite being set-stocked at about 12 ewes/ha, compared to the one ewe/ha they put on unimproved pasture.

“On this dry country that’s a relatively high stocking rate and the increased growth rate [of the lambs] means we’re able to wean earlier, and heavier. Last year they were about 29kg/ha when we weaned at the end of January.”

This year he’s pushed that stocking rate to 18 ewes/ha but whether the same growth rates are achieved remains to be seen.

His lucerne stands support similar stocking rates and have achieved slightly better average lamb growth, at 205g/day, but lupin’s much lower establishment and maintenance cost more than makes up for the difference, he says.

Not only that, lupin’s early and late growth provides feed for ewes and lambs when it’s most needed, and it will grow well where lucerne won’t due to low pH and/or high aluminium.

“The biggest problem with lucerne is it just doesn’t grow for four or five months of the year. Where we can grow it, normally we get about 9tDM/ha/year off it. With lupin we’re getting 15t/ha of drymatter.”

Based on the results of trials at nearby Mt John (see sidebar), a lupin stand is also likely to persist for decades with minimal input, whereas even with good management lucerne is likely to run out in about 10, he adds. “We’re just getting going with lupin after ten years.”

 Loxton’s experimenting with ensiling, with Lincoln University helping gather and in due course, analyse, data. He’s also trying sowing lucerne with lupin.

“Leaving the grasses out of the mix means it should be easier to control problem grasses like hair grass.

Experience has shown drilling with urea, DAP and Sulphur Gain down the spout improves establishment, which in turn speeds improvement of the pasture. Only 2kg/ha of seed is used through a conventional Duncan triple-disc drill and within 2-3 years the lupin starts flowering and seeding to fill in the stand. “We just fill the drill with seed and go drilling.”

They’ve found no need to inoculate seed as the soil appears to contain the right strains of rhizobia to colonise root nodules and fix nitrogen.

“The nodules are perennial and don’t slough off in times of stress like they do with lucerne and clover,” notes Loxton.

Another advantage of the species is its low maintenance and flexibility.

“In a tough year for meat and wool returns we don’t have to put any fertiliser on and we’re not using herbicides either. With lucerne if you don’t keep up the annual management you’re likely to lose the stand.”