BEEF producers thinking about renovating paddocks with perennial pastures have been warned to plan ahead.
That was the message from Manjimup pastoralist Kim Skoss after he conducted a three-year perennial pasture demonstration supported by the South West Catchments Council (SWCC).
The avocado and beef producer runs 35 hectares west of Manjimup and started the demonstration in 2013 in the hope of reducing supplementary feeding during autumn and winter.
After a 5ha trial planting perennial phalaris, cocksfoot and lucerne in combination with arrowleaf and sub clover, Mr Skoss concluded at least one year of preparation was needed to ensure perennials have a clean seedbed and good soil fertility.
SWCC project manager, sustainable agriculture Peter Clifton said low phosphorus levels in the soil at the trial site were a major inhibiting factor.
Soil tests taken on the Manjimup demonstration site prior to sowing found low phosphorus levels and a high phosphorus buffering index (PBI).
“Basically the high phosphorus or high PBI soils really are a major soil constraint that people probably need to deal with before they start investing money in the paddock,” Mr Clifton said.
“You need to get some available phosphorus in the soil and whatever product you use, you need to know how quickly it will be available.”
A high level of phosphorus was applied to the demonstration site made up of primarily gravelly-loam soil, and the crop was sown at a depth of 5 millimetres to 10mm in June 2014 after weeds were sprayed.
Germination followed and fertiliser was applied at 150 kilograms a hectare, but growth was slow over the first spring.
After 12 months Mr Skoss estimated ground cover had reached 66 per cent.
More phosphorus was applied at 330kg/ha in May 2015 but soil tests in 2016 found phosphorus levels were still low, and the paddock continued to underperform.
In 2016 the number of cow grazing days per hectare was 198, compared with 286 for an adjacent annual paddock.
In late 2016, as the demonstration neared completion, Mr Skoss hosted 14 farmers at a field day.
While the paddock hadn’t performed as well as hoped so far, he was still encouraged by the widespread seed-set of phalaris over the summer of 2017, and the regrowth from the recent summer rain.
Mr Skoss recommended controlling annual grasses and addressing fertility issues before sowing perennials.
“I should have seeded down a grass legume mix in the first year with a capital application of phosphorus,” he said.
“Then in 2015 I could have grazed the residue and direct-seeded following the application of a knockdown herbicide.”
Mr Skoss advised farmers to speak to an agronomist, work on hitting weeds with at least a double-knock, soil testing to address fertility issues and applying fertiliser down the shoot with seed.
He also recommended shallow sowing at double the recommended rate to minimise the risk of failure.
Mr Clifton said the trial showed it was also beneficial to rest perennial crops to ensure they could compete with annuals.
“It’s really a matter of giving it time to establish, I mean the perennials are slow establishing and that’s one of the issues with them, they have small seeds and they take a bit of time,” he said.
“That rest period does appear to be quite critical and if people don’t do that, then basically after three years there’s nothing to be seen as far as perennials are back where they started.”