Putting summer-sown legumes to the test
Location: Esperance WA
Enterprise: Wheat, barley and canola cropping. Self-replacing Merino flock. Terminal maternal ewe flock. Shorthorn and Angus commercial cattle herd
Producer: Simon, Jon and Bob Stead and their families
Soil type: Sand over gravel over clay, running into transitional Mallee country
Pasture type: Traditionally sub-clover-based improved pastures with some medics and wimmera ryegrass. About 10% of pastures now hard-seeded legumes
Simon Stead is optimistic about the potential for hard-seeded legumes to replace struggling sub-clover in his pasture-crop rotation. He’s particularly impressed by the convenience of summer sowing – an option for some of the legume varieties.
Simon farms in partnership with his father Bob, brother Jon and their families, and has sown about 2,000ha of hard-seeded legumes in the past two years.
“We’ve got a major problem on the south coast with red clover syndrome,” Simon said.
“Our sub-clovers are coming under stress and dying out before the end of the season – anywhere from June.
“We’re being left in a hole from a nitrogen-fixing and a feed point of view.”
In 2011, Simon took part in a pasture tour with the ASHEEP grower group, led by Angelo Loi, Brad Nutt and Ron Yates from Department of Agriculture and Food Western Australia, and consultant Neil Ballard.
“We travelled around the south-west and saw these legume varieties performing well in pretty harsh conditions,” Simon said.
“It was an inspiring trip, so I came home and seeded about 1,000ha of new pasture.”
In late autumn/early winter 2012, the Steads sowed 700ha of biserrula, with the balance made up of bladder clover, Santorini yellow serradella, Margarita French serradella and Prima gland clover.
“We had pretty good seed set, though some varieties did better than others,” Simon said.
“The bladder clover, for example, grew massive amounts of feed and we harvested seed.”
In 2013, the pastures went back under canola, and this year those paddocks will return to pasture.
“This will be the true test,” Simon said. “If they don’t persist, they’re no good to me.”
Simon said it was difficult to gauge how much nitrogen (N) the previous legume pasture had contributed to the 2013 canola crop, however he did small trials of different N rates.
“They all had starter N at sowing time and visually you can’t see any difference between the areas that had 0kg N/ha, 40kg N/ha and 80kg N/ha applied at the start of flowering,” he said.
The area with 0kg N/ha displayed a yield advantage over canola grown on paddocks which hadn’t previously been sown to legumes. However, Simon found as the N rate went up so did the yield.
“It was an abnormal year with 300mm more rainfall than the average annual rainfall, so we will continue these trials to assess the impact of the legumes with the view to, at times, being able to reduce the amount of N we need to apply,” he said.
The Steads summer-sowed 300ha of Margarita French serradella in February 2013. With 180mm of rain falling in March – contributing to a 700mm total by the end of October – the results were “phenomenal”.
“All our pastures came up – and it was our best sub-clover year in 10 years,” Simon said.
“However, red clover syndrome kicked in and chopped a lot of it off, whereas the serradella was still green, flowering and setting seed at the end of October.
“Where we swathed (windrowed) the canola you could see a carpet of biserrula and Santorini under it, and a little bit of bladder clover too.
“The legumes are supposed to be so hard-seeded that nothing should germinate in the first year after they set seed, but I think when you get 700mm of rain you get a fair bit of seed softening.”
The Steads traditionally re-sow about 30% of the cropping area back into pasture in winter, but Simon says this may rise to 40% if the legumes perform well.
“We’ll then work a rotation of two crops to one pasture and, if the pasture starts to look a bit dodgy, go to two years of pasture to let it build up,” he said.
“Now we’re waiting to see which varieties will be the most persistent.”Esperance WA
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