South West

Effective establishment of grazing cereals with perennials in high rainfall WA

This trial is now complete

Key Messages

  • When perennials are sown with cereals, gross margins (GM) can increase significantly due to grain sales. But the benefit of grain production is off-set by reduced perennial production.
  • The farmers involved with the trial agreed that the perennials establish much better when sown alone as compared to being sown with cereals.
  • The trial reinforced the value of sowing a cereal alone in year one to prepare the paddock, allow some cereal grazing and maximise grain yield, and then establishing perennials in year two.
  • Rotating stock in and out of the paddock has been important for perennial persistence, even with annual grasses coming back into the system.
  • Trial Rationale
  • Steps Taken
  • Lessons Learnt
  • Looking Forward

Trial Rationale

The Manjimup Pasture Group believe that around the Manjimup, Bridgetown and Boyup Brook area, perennials such as Phalaris, Chickory and Lucerne have the capacity to increase productivity and profits in livestock systems.

By improving summer feed quality and responding quickly to summer and autumn rain, perennials can help reduce supplementary feeding, defer grazing from annual paddocks at the break of season and flush ewes for improved reproduction.

But establishing perennials can be expensive due to the loss of production.

‘Traditionally, if you are going to establish perennials, you would spray the grasses out in autumn, allow some grazing around August/September and lose production in between,” advisor Paul Omodei said. “We want to establish perennials while still feeding the livestock and not compromising stocking rates.”

Previous work by the Manjimup Pasture group has shown that cereals can be grown in the Manjimup area.

This trial aimed to demonstrate the most effective and cost-efficient method of establishing perennials with cereals to maintain production during establishment, and comparing it to perennials sown by themselves.

Steps Taken

The trial was established in 2014 with six treatments sown in 100 m long strips. There were two replicates of each treatment.

The trial compared six different methods of establishing perennial pastures:

  1. Shallow sown perennials (Control) – no seed treatment – no cereal. The perennial mix consisted of phalaris (Advanced AT – 2 kg / ha), Lucerne (SARDI & Series II – 2 kg/ha) and chicory (Commander – 1 kg/ha).
  2. Skip row sowing: deep cereal / shallow perennial sown six inches apart.
  3. Same row sowing: deep cereal / shallow perennial (both sown at ideal depth with a tyne machine and press wheel. Seed boot tied to the back of the tine to drop perennial seed in front of the press wheel – done simply by using a Duncan drill and cable ties)
  4. Same row sowing: Shallow cereals and perennials (a common option when sowing perennials with a cover crop is to sow all species at a shallow depth for perennials. This normally disadvantages the cereal which will generally yield less than deep sown cereals.)
  5. Shallow sown perennials + seed treatment (mycorrhiza and nutrient seed treatments) – no cereal
  6. Same row sowing – deep cereal / shallow perennial (minus Lucerne in perennial Mix), because some people in the group do not think we could get productivity of our Lucerne.

The site had two cultivations and a knock down and was sown in June with 40 kg/ha of Agras. Grazing was planned for August but the perennials in the “no cereal” treatments weren’t established sufficiently.   

 Monitoring techniques included biomass cuts, plant density measurements, grazing days, grain yield and gross margin.

Lessons Learnt

The trial showed that when perennials are twin-sown with cereals, gross margins (GM) can increase significantly in year one due to grain sales. The twin-sown treatments yielded three to four tonnes per hectare of wheat and resulted in first year GM of between $500 and $700/ha. This compared to a loss in GM of between $20 and $115/ha in the perennial-only treatments.

As expected, this grain production was off-set by reduced perennial production. After grain was harvested in January 2015, mean total dry matter (DM) was measured, with perennial-only plots averaging 1,894 kg/ha, compared to 119 kg/ha when perennials were sown with cereals.

Treatment 6 (deep cereal / shallow perennial without Lucerne) resulted in the highest grain yield, but also the lowest perennial biomass. The poor establishment led to this treatment being sprayed out in 2015 and re-seeded to perennials-only (including Lucerne with seeds untreated). This essentially mimicked the practice of growing a cereal in year one to help prepare the paddock and then establishing perennials in year two.

The difference in GM between perennial-only treatments and some twin sown treatments narrowed by the end of the trial.

The farmers involved with the trial regularly met at the property to follow its progress. While they learnt that it’s possible to establish perennials with cereals, they all agreed that the perennials established much better when sown alone.

Host farmer Phill Rose says perennials germinated well enough with cereals, but the resulting sward wasn’t thick enough.

“Probably in hindsight I would go with perennials by themselves,” he says. “You just have to work the shortfall of income into your budget.”

The practice of the practice of growing a cereal in year one to help prepare the paddock and then establishing perennials in year two, which was essentially incorporated into the trial when Treatment 6 was re-seeded, was competitive in terms of gross margin by the end of the project (only $121/ha less than best twin-sown treatment). This outcome occurred despite the higher costs from an extra year of weed control, fertiliser and pesticide. It’s also worth noting that because this treatment was initially twin-sown, the wheat yield of four tonnes per hectare could have been higher.

“I had hoped to yield five to six tonnes of wheat, but sowing wheat with perennials meant we needed more weed control and the crop didn’t go in until late June,” Mr Omodei explains

This strategy also had the highest plant density of all treatments in December 2016.

Another disadvantage of twin-sowing is that low seeding rates were used for the perennials to ensure there wasn’t a significant yield penalty on the grain. But many growers prefer to double recommended seeding rates to give small-seeded perennials a competitive advantage over weeds.

These results demonstrate that establishing a cereal crop in year one and perennial pasture in year two is an attractive option. This strategy has a strong focus on the crop in year one (nutrition, timing, weed control) and can more easily incorporate grazing of cereals, something that proved too risky to attempt in twin-sown plots when perennials were establishing.

The trial also provided some valuable observations about the individual species. Phalaris performed poorly in a mix, with some in the group commenting that it can be outcompeted if there is grazing pressure at the wrong time. Lucerne performed better without irrigation than some farmers expected, and chicory was considered “incredibly resilient” once it was established. Both chicory and lucerne also showed significant natural recruitment over the summer periods.

The performance of lucerne and chicory is likely to be a response to resting the paddock after grazing. Mr Rose believes rotating stock in and out of the paddock has been important for their persistence.

“I think you need to have two or three patches (of perennials) so you can get a rotation going, and maybe a bit bigger (than the two hectare trial area).”

The fact that perennials have persisted despite a significant germination of clover and annual ryegrass in year two has encouraged the group, who believe that having a strong perennial grass with annual ryegrass and clover coming back into the system is ideal.

“The thing to understand is that it’s not all about perennials,” Mr Omodei says. “We’ll still have an annual part of the system to carry stocking rates in winter.”

The benefit of having perennials in the system was highlighted by feed tests taken in November 2015. The results showed that perennial species maintained very high feed quality late into the growing season, despite a poor spring that year. Notably, the phalaris displayed significantly higher crude protein than annual ryegrass, and chicory had the highest metabolisable energy (ME). The range of ME across all perennial species exceeded minimum requirements for all classes of sheep except early lactating ewes, and the crude protein content was high enough to meet minimum requirements for all classes of sheep, including weaners and lactating ewes.

Looking Forward

Growing enough of this quality pasture is another cost to consider in adopting perennial pastures. Mr Omodei points to modelling which suggests the full benefits of the system are seen when farmers have 20 to 30% of the farm in perennials. This is not only an additional factor for considering cost, but also relies on having enough land suitable for perennials.

“You need to know what parts of the landscape can handle perennials and that is the secret about working out how much land you allocate to them,” he says. “In Manjimup and the South West, they are more suited to areas with prolonged water at the end of the year. If you only have 10% of the farm suitable, you might still use that for flushing ewes or joining young stock, but you are not going to be able to put much weight on a young animal.”

Nevertheless, some in the group are more interested in doing small pockets around the farm that aren’t used for hay, and doing them properly. The benefit of this approach is that they can better manage risk by limiting costs, while making sure the perennials will persist well into the future.

Full technical report is available at https://swccnrm.org.au/library/download-info/2014-2017-technical-report-manjimup-pasture-group/

Manjimup

Project Snapshot

Land Manager
Phill and Diane Rose and Manjimup Pasture Group
Shire:
Manjimup
NRM Region:
South West
Property Size
325 ha
Average Rainfall:
Very High - More than 750mm
Enterprise Mix:
Horticulture with farmland grazing
System Constraint:
Autumn-winter feed gap
Partners:
Manjimup Pasture Group, NLP, SWCC
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