Russell lupin: saviour of the Mackenzie Country, or invasive weed?

Gavin (Snow) Loxton of Sawdon Station sees the value of russell lupin as a nitrogen fixing, low input sustainable feed ...
Pat Deavoll

Gavin (Snow) Loxton of Sawdon Station sees the value of russell lupin as a nitrogen fixing, low input sustainable feed for merinos.

Mention russell lupin and stand back for the opposing reactions among tourists, authorities and farmers, writes Pat Deavoll.

Loved by  tourists for its colour, reviled by the Department of Conservation as an invasive weed and coveted by a growing number of Mackenzie Basin run holders as pasture - lupinus polyphyllus, or russell lupin must be one of the most contentious plants in New Zealand.

In one camp is retired AgResearch scientist David Scott of Tekapo. He claims russell lupin to be the most exciting of all pasture species he has studied. It is a "long-lived and nutritious sheep feed that needs little fertiliser," and "a viable pasture option for a particular set of environmental and soil conditions for a sector of merino grazing lands." 

Showing the nitrogen fixing nodules in a russell lupin.
Pat Deavoll

Showing the nitrogen fixing nodules in a russell lupin.

Lincoln University professor Derick Moot supports Scott's claims, saying russell lupin will enable many high country farmers to grow out lambs ready for slaughter - good news when their down-country finishers graze dairy cows instead.

In another camp DOC ecologist Nicholas Head says russell lupin has spread into riverbeds in the Mackenzie Basin, where it poses a risk to native ecosystems. What's more, in 2014-15 DOC spent close to $147,000 controlling the spread of the plant in the Mackenzie Basin and is budgeting on doing the same for the upper Waitaki this year.

Sitting on the fence, Environment Canterbury's (ECan) Canterbury Pest Management Strategy lists russell lupin as a biodiversity protection pest, meaning people are free to plant it without being required to control it. Head questions ECan's neutral stance, saying "they are spreading; sheep are not controlling them and carry seed in their fleece. And landowners take no responsibility."

Russell lupin: invasive weed or valuable high country pasture?
Wendy de Groot

Russell lupin: invasive weed or valuable high country pasture?

Russell lupin has, through the eyes of Mackenzie Country farmer Gavin (Snow) Loxton, the power to transform his run holding from what is threatening to become a  wasteland of invasive hawkweed and wilding pine into productive pasture.

"It's a perennial that grows from early spring until well into winter. Trials confirm that it survives heat and cold, and can be sown into existing pasture with little cultivation and fertiliser. Its long roots add nitrogen to high-acid, high-aluminium soils not tolerated by lucerne, while protecting against erosion by wind and rain. If we did nothing the land would be de-stocked and covered in wilding pines. This is what we are up against and what russell lupin can help ward off."

Scott confirms Loxtons claims, saying russell lupin is most suited to rocky, sandy or loose-textured soils of low to moderate fertility and with low competition it is likely to become the dominant species. The Mackenzie Basin is ideal for its growth, he says.

Russell Lupin pasture on Sawdon Station in January after flowering.
Pat Deavoll

Russell Lupin pasture on Sawdon Station in January after flowering.

Unfortunately these very same traits make russell lupin an invasive pest for DOC. It forms dense, self-replacing stands which prevent native plants from establishing. It adds nitrogen in the soil  encouraging nitrogen seeking weeds which crowd out low fertility native species. It causes sand and gravel to build up, contributing to flooding and erosion. And the increased cover prevents some birds from nesting and increases predation from cats and stoats for nesting birds.

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The first major investigation into the potential of russell lupin as a feed for merinos was started by Scott in 1982 at Mt John Station. It was established russell lupin could be the main component of a mixture for standing maintenance feed for autumn and early winter, and as a component for early spring feed. Its large size would also provide shelter as a replacement for tussock.

Loxton and wife Sue have farmed 7600ha Sawdon Station, sited in the northeast corner of the Mackenzie Basin, for 20 years. They run 4000 merino ewes and a few trading cattle. The first major sowing of russell lupin in the Mackenzie Country was on their property on the bare roadside soils in about 1952. 

On the left, Department of Conservation land; on the right Sawdon Station land that has been planted in russell lupins.
Pat Deavoll

On the left, Department of Conservation land; on the right Sawdon Station land that has been planted in russell lupins.

The Loxtons are trying to simplify their farming system, and see a place for russell lupin in this venture. 

"Farming is inherently lots of capital and  labour, and we are trying to simplify this by reducing labour input," Loxton says. "We can't reduce the capital because land prices just keep going up. But by growing more perennial forage crops, we hope to decrease the cost of production, and russell lupin fits the bill for a low input system."

Loxton sees a part for russell lupin in improving his lamb growth rates to increase returns. His store lambs used to sell into Canterbury but with dairy taking over the grazing, that has gone by the wayside. He needs to get the lambs a bit further along as people are more prepared to buy them if they are nearly ready for the freezing works - and sees lupins playing a big part in this.

Merinos eat russell lupins, but cattle are less likely to, Loxton says. The sheep rumen has the ability to digest the alkaloid component of the lupin. He says russell lupin is not particularly acceptable to stock during summer because of the alkaloids in the leaves. Young flower buds are often the first part eaten. All parts are eaten in spring but leaves are then grazed progressively less. All plant parts become acceptable again during autumn.

"A four-year Lincoln trial on our property comparing lucerne with lupins found merino ewes and lambs gained similar weight on both. Ewe pregnancy weights, lambing rates and wool production were also similar," he says.

Loxton planted his first trial crop of russell lupin in 2003. As a leaseholder of publicly owned land he had to apply to the Commissioner of Crown Lands to plant the crop, gaining permission to grow 1100ha. To date, he has planted 200ha.

"It was established under a cereal crop of oats and barley," he says. "Because it's a perennial, it exists along with native grasses and flowering plants like blue borage. Everyone got very excited about it and in 2011 the trial was included in the Primary Growth Partnership (between government and industry investing in programmes to increase the market success of the primary industries) to establish how well russell lupin went as a forage crop." 

There are many ways to plant lupins, he says, and they are slow to establish. It's important to improve sulphur levels in the soil first through top dressing for the Mackenzie is notoriously light on sulphur. The ground is then sprayed with Roundup. On land unsuitable for drilling Loxton spins the seed in with a fertiliser spreader, and harrows it into the ground. Another method is to allow stock to trample it in, he says, although it is best to keep stock off while the crop is establishing. He might sow a little coxfoot grass with the russell lupin, but never a high fertility grass like ryegrass. 

Scott says shallow spring drilling is probably the best method, but it should remain ungrazed for the first one to two years or at least until some plants reach the height of 30-40 centimetres. The "long-term vigour" of any legume stand depends on good growth of root systems and nodules during the establishment period.

There are advantages of lupin over lucerne, Loxton says. Lucerne is a monocrop and a high fertility species that needs fertilising regularly. It also needs spraying to keep grasses down to maintain it as a monocrop, and after about 10 years it will need replanting.

On the other hand perennial lupin, as a low input system, produces a lot of dry matter and as long as this can be controlled by grazing, the crop will last indefinitely. It keeps growing, producing so much nitrogen and organic matter, that the other grasses grow up, over-run it and it dies out. But it leaves hard seed in the soil, and re-establishes itself next time there is a "catastrophe" like a flood.

"One thing we are working on now is putting cattle into the system to keep the grass down and keep the lupins fully established. It's hard because they produce so much growth in spring and it takes a very high stocking rate to keep the grass around them under control."

Another advantage of lucerne over lupin is that lucerne has a short growing season, which limits the time it has for nitrogen fixing.

"When lucerne gets frosted it puts all its energy into staying alive, rather than fixing nitrogen. But lupin is very frost tolerant. It has perennial nitrogen-fixing nodules - lucerne has an annual nodule that it sheds when conditions get bad."

Loxton and Scott are trying to "domesticate" the russell lupin. They started in 2003 with some seed "from the side of the road" and are now trying to produce their own low-alkaloid cultivar. They decided the plant needs to be lower in alkaloid to be more palatable to sheep, Loxton says.

To date, they have tested 13,000 plants for alkaloid levels and replanted those registering positively low in a trial plot. They don't know why these plants are low but intend to find out, Loxton says.

"In five or 10 years, if we can keep our costs low enough, we should have our own cultivar."

Lupins won't spread onto DOC land that hasn't been fertilised, Loxton says. 

"It's a myth that lupins will take over the world - there needs to be a certain level of sulphur in the system before it will establish. But there is no way to halt the spread in the riverbeds - that horse has bolted. The seeds germinate readily in areas of disturbance like creeks and river beds. Saying that, DOC doesn't seem interested in what we are doing here - they've never visited or attended our field days."

Loxton says as he brings more land in he will add lupins. He is hoping to freehold land through the tenure review process. 

"Russell lupin? I've picked it up and run with it," he says.

 - Stuff.co.nz

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