Back to the future with sub clover
Sub clover is making a comeback in hill country farming with a new seed crop in Canterbury the first grown nationally in at least 50 years.
Canterbury company Luisetti Seeds has begun the first stage of multiplying seed from a New Zealand variety developed by AgResearch for hill country growing in the dry east coast belt and summer dry farmland outside of the high country.
In another month the small crop planted in Mid-Canterbury will be removed from weed mat to provide about two kilograms of seed. The seed will be sown this February to increase numbers with commercial amounts expected to become available in 2016.
Retired Lincoln University lecturer Dick Lucas said the seed crop was the first grown for many years and once multiplied would provide a secure supply of sub clover to meet promising demand.
"We believe there was a Blenheim grower who grew sub clover seed in the 1960s and some was grown throughout New Zealand in earlier periods from the 1930s, but nevertheless most of it was imported with some farmers taking their own and feeding sub clover hay into a stationary header, but it wasn't a big crop."
Lucas said growing seed would bypass biosecurity restraints for bringing it in from Australia which was prone to floods, fires and droughts.
Before World War II sub clover was widely sown and for several decades afterwards remained in favour. Farmers stopped sowing the plant and left it to self seed itself until wet years interrupted its reproduction in the 1970s. Then the concept of all grass wintering came along, favouring ryegrass and white clover despite this clover struggling in hot summers.
Lucas said sub clover had only regained favour during the last 15 years, mainly among younger farmers and for a long time only "fathers and grandfathers" remembered growing it on hills and in strong lismore soils on the flats.
Annual clovers and particularly sub clover was now building a "head of steam" as it was easy to grow and manage, he said.
A 10-year grazing trial by Lincoln University, ending last year, showed sub clover and cocksfoot pastures outperformed a cocksfoot and white clover mix by 30-40 per cent depending on the season with lucerne recording the best liveweight gains on sheep.
Sub clover seeds are stored in the ground and large vacuum harvesters are used to raise them which can lead to it being contaminated with sheep manure and other seeds.
After bringing sub clover varieties from Australia Luisetti has chosen to multiply seed itself. Sales of imported Australian varieties doubled last year to 20 tonnes.
Luisetti agronomist Andrew Johnston said perennial ryegrass and white clover had been the mainstay of farming, but the only way to feed lactating ewes and sell lambs without lucerne in steeper country was with sub clover as it could be oversown in autumn.
The self pollinating plant had a large seed and, if left ungrazed, its long runners could grow to one metre wide. By Christmas the plant died off, setting its seeds in the soil.
The seed is $10 a kilogram and sown at 10kg a hectare at about $100/ha.
Johnston said sub clover on a 25ha block at Mt Benger station had good striking rates outside of a developed area as its big seeds had lodged in hoof marks.
"That's very promising because it means it's well adapted for being oversown by aircraft."
The area was sown in February and not set stocked until June.
He said the key was to sow seed in a heavily grazed pasture and rest it from May to June for the best results.
Cheviot farmers had closed sub clover to stock from October to December during the flowering period when seed was set and successfully re-established seed buried in the ground the previous spring.
Sub clover can produce 200-250kg of seed a hectare and commercial seed growers 1.5t/ha with vacuum harvesters.
Johnston said the late flowering New Zealand bred variety selected by AgResearch at the Whatawhata research centre was well suited for New Zealand conditions.
"Because of the biosecurity issues [to import seed] it's important we have a variety for New Zealand conditions for farmers. It's a selection for New Zealand hill country. The only seed on the market so far has all been bred in Australia."
The variety suits hill country with 700-1000mm of rain and drought-like conditions over two to four months during summer.
At a sub clover field day at Mt Benger station in North Canterbury last month farmers were educated about establishing and managing the newly introduced varieties selected by Lucas and Lincoln University's Dr Derrick Moot. Sub clover was successfully introduced at Mt Benger with lucerne used as a finishing feed to put weight on lambs.
Sub clover is fed during the lactation period when lambs are still with their ewes and at four weeks they then go on to lucerne.
- © Fairfax NZ News
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