Legumes under the spotlight

Legumes under the spotlight

Monday 1st November 2021

Legumes under the spotlight for Hill Country Futures Programme

Take home messages

  • Legumes have the potential to transform hill country farming businesses while protecting vulnerable landscapes.

  • Address nutrient deficiencies to allow legumes to photosynthesize and fix nitrogen.

  • Correct management of sub clover is critical to maximise its productive potential in early spring.

  • Talk to seed agents about the cultivars most suited to individual farm environments and systems.

  • Satellite farms within hill country can have significant production and environmental advantages.

  • Rotationally graze as soon as possible after lambing to help drive pre-weaning growth rates.

Legumes are the powerhouse of pastoral farming systems, and with the correct management, have the potential to transform farm businesses while protecting fragile hill country landscapes.

Capturing the power of legumes was the subject of a recent Hill Country Futures’ and Luisetti Seeds’ field day, which shone a spotlight on how legumes can be used both on hill country and finishing country to drive economic and environmental efficiencies.

The Hill Country Futures Partnership programme is a five-year project co-funded by Beef + Lamb New Zealand, the Ministry of Business, Innovation and Employment, PGG Wrightson Seeds and Seed Force New Zealand. The programme is focused on future-proofing the profitability, sustainability and well-being of New Zealand’s hill country farmers, farm systems and rural communities.

Within the programme, there are four research areas – all contributing towards the overall objective of future proofing New Zealand’s hill country farms and rural communities.

Mt Benger, a 2810ha hill country farm in North Canterbury’s Hurunui District hosted the field day and is typical of many east coast commercial breeding operations where the focus is on maximising the number of lambs sold prime at the weaning draft.

This not only has financial benefits, but it also reduces the amount of methane produced by the lamb crop, takes pressure off hill country landscapes and allows summer feed to be partitioned back into the ewes so they are at optimum body condition going into mating.

Mt Benger, like much of this country’s hill country, has subterranean clover as an endemic pasture species within the sward. This is a legacy of the 1950s and 60s when sub clover (usually Mt Barker) was flown onto hill country in the early days of aerial topdressing.

What was lacking was an understanding of how to manage this clover so that it would create a bank of feed in early spring to drive lactation and maximise pre-weaning growth rates.

Ten years ago, the management team on Mt Benger looked to augment existing sub clover with new varieties in a 25ha block known as Alice’s block.

Sub-divided from a larger 236ha block, Alice’s block was thick with matagouri and growing Danthonia and browntop. Small amounts of native suckling and striated clovers hinted at this block’s ability to grow legumes.

In 2011/12, the woody vegetation was cleared and lime was applied. A mix of rape (at 3kg/ha) and Woogenellup (3kg/ha) sub clover was flown on along with 150kg/ha of Sulphur Super in the first week of February. The area was then harrowed.

Steers grazed the block over winter and in spring it was shut up to allow the clover to set-seed. In January 2013 it was grazed by cattle to open up the sward before being lightly disced to chop up re-growth rape. The following month, Porto Cocksfoot (5kg/ha), Ruanui ryegrass (10kg/ha), Antas sub clover (5kg/ha), Monti sub clover (5kg/ha), Huia white clover (3kg/ha) and plantain (1.5kg/ha) was flown on.

The results were and continue to be impressive.

In that year, the block was grazed by 500 ewe lambs from early May to early June and set-stocked with 100 twin-bearing ewes from the end of July.

Alice’s block is now rotationally grazed by ewes and lambs post-tailing to try and maximise pre-weaning growth rates and the weaning draft. It is typically shut up in autumn to allow pasture covers to build for spring.

Speaking at the field day, Lincoln University-based plant scientist Professor Derrick Moot described the mix of sub clover and cocksfoot as an ideal dryland pasture mix.

The space between the drought-tolerant cocksfoot allows the clover to flourish without competition, while the clover supplies the cocksfoot with nitrogen, keeping the plant growing and palatable.

The success of sub clover on this block has highlighted the potential of legumes in the hill country and now, under a new management team, the focus is on applying the same principles to other parts of the farm.

Nutrients needed for nitrogen fixation.

Professor Derrick Moot says for sheep and beef farmers to continue to drive production efficiencies and continue to reduce their environmental footprint, they need to recognise the resources they have on their farms and utilise them to grow animals quickly.

To do this, they need to get nitrogen into their system to address the perennial issue of nitrogen deficiency. Legumes do this in the most efficient, cheapest and environmentally sustainable way possible.

In order to fix nitrogen, legumes need moderate levels of sulphur and phosphorous – the latter for photosynthesis and nitrogen fixation – along with pH levels of around 5.7.

Molybdenum is also needed for nitrogen fixation.

Speaking at the field day, soil scientist Jeff Moreton, says some soils, especially those in lower rainfall areas, rolling downs or hills lack molybdenum. He recommends testing every four or five years and correcting deficiencies with 50gm/ha.

Testing for molybdenum deficiency is difficult and is the subject of a trial being carried out at 21 test sites on dryland east coast hill country.

Introducing sub clover to hill country pastures

Lincoln University’s plant scientist Dick Lucas says September is the best time to assess the presence of sub clover in pastures by looking out for sub clover’s idiosyncratic white flowers.

Striding up a hill, Dick told farmers that if they step on a clover patch every second step (about every two metres) then, with the correct management, there is enough clover to drive livestock production.

Any less than this and he recommends either over-sowing or drilling with more than one cultivar of sub clover, the following autumn. A mix of large and smaller leaf varieties is ideal – along with a mix of flowering dates.

Cultivar suitability also depends on the environment, so Dick suggests that farmers talk to their seed agents and order the seed early.

To increase sub clover populations, the area identified should be spelled from mid-September or grazed with cattle to keep grass under control for up to eight weeks. This will allow seed-set.

Once the sub clovers runners have “pegged” their seed (test by giving the runner a gentle tug) the area can be grazed down by cattle only. Sheep will target the sub clover runners and eat the seeds.

Over summer, the block can be grazed to reduce pasture mass. Autumn rain of more than 20mm will trigger germination after which the area should be spelled to allow the seedlings to reach the 3-4 trifoliate leaf stage. The block can then be lightly grazed, preferably by cattle to control grass competition.  In winter, it is recommended that the area is grazed to 1200kg DM/ha and in spring, the sub clover will produce a bank of high-quality feed for lactating ewes and lambs.

Satellite farming

Alice’s block on Mt Benger is a good example of the potential of “satellite farming” on hill country. These are intensively managed smaller farmlets within larger, more extensive blocks.

Appropriate areas are identified for more intensive development and once fenced off, these are typically used for maximising pre-weaning growth rates in lambs or for growing out cattle.

These satellite farms take pressure off the hill country landscapes and allow these areas to recover and build pasture covers during spring and early summer which can then be used to increase the body condition of breeding stock over summer and autumn.

By giving livestock the opportunity to realise their genetic potential, these satellite areas drive profitability and the cost of the development is then disseminated over the whole area. Professor Moot commented that this concept is an extension of successful satellite areas of lucerne and red clover being used on small cultivatable areas that then support the hill areas around them. 

Further sub-division of Mt Benger’s hill country is planned along with the development of 500-600ha hill country pastures.  Manager Stuart Fraser intends developing around 100ha annually, into sub clover and improved grass pastures.

Peter Anderson

Former StockCare vet Pete Anderson enthuses about legumes.

“I’m a great fan of legumes because farmers who are using legumes, are getting the best results.”

When analysing stock performance through StockCare programmes, they found lambs on dryland properties in Marlborough and North Canterbury were growing faster than anywhere else in the country. The reason was the sub clover in their pastures.

“I have since been a convert.”

He says the only true measure of sheep production is the kilograms of lambs weaned per kilogram of ewes mated. This figure is driven by the lambing percentage and weaning weight.

Weaning weight is driven by age and lamb growth rates and lamb growth rates are driven by the availability of high-quality forage, particularly legumes.

“Since we started to learn how to manage sub clover, we have seen some huge changes on hill country properties, simply by changing management.”

Peter cited examples of four hill or high-country farms, Tempello near Blenheim, Bonavaree near Seddon, Dumgree in Marlborough and Bog Roy in Omarama whose businesses have been transformed by harnessing the power of legumes.

Within four years of learning how to manage sub clover, the lambing percentage in Tempello’s Corriedale ewes increased by 33% to close to 150% and lamb growth rates lifted by 142g/day to just under 400gms/day.

As well as learning how to manage sub clover to harness, Tempello’s owners got their ewes and lambs on a rotation as soon as possible before tailing, and this has been critical to driving pre-weaning growth rates,

Bog Roy started using grazing lucerne, rather than just using it as a supplementary feed, and this has proved transformative.

Peter says the main change on Bog Roy was the lift in ewe condition. This has pushed lambing percentages to over 140% in their Merino ewes and allowed them to mate their hoggets.  It has also taken pressure of the hill country while allowing them to carry an extra 900 ewes.

He says the three key principles to utilizing legumes is resting lambing blocks to allow sub clovers to build prior to set-stocking, to start rotational grazing as soon as possible after lambing and sub-division to enable better pasture management.


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