A TRIAL of Subzero hybrid forage brassica on the Collins family farm at Corny Point has surpassed expectations, with the grazing variety filling a vital feed gap in the crop and livestock operation.
Rodger and Chris Collins farm with sons Michael and Declan and farmhands Robert Mason and Ian Steggall, cropping wheat, barley, canola and lentils, alongside 2500 Merino breeding ewes, on the lower Yorke Peninsula.
Michael said they had seen Subzero being grown throughout the state since its release in 2015 and had been curious about the annual pasture.
"Brassicas are not very common down here, with medic more often grown, but then a few farmers started growing it in this area, so we thought why not give it a go?" he said.
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Local S&W Seed Company territory manager James Cook said Subzero's excellent regrowth meant it could be frequently grazed, but still retain its leaf and stem quality even through cool seasons.
Michael said they were attracted to the winter active pasture for its capability to provide feed year-round and its frost tolerance.
The Collinses started by putting in a 50-hectare trial in early April 2019.
"We were able to put our ewes and lambs on it six to eight weeks later, which was really quick, and they seemed to really like it," Michael said.
"In that first year, we never let it go to seed and then we got late spring/summer rains which kept it growing - whereas other pasture species just go to seed when it gets too hot. If you've got the moisture, it can grow year-round and we have reasonably reliable rainfall here."
We see Subzero as a good green feed gap from October to the end of December, until we can get our sheep onto stubbles.
- MICHAEL COLLINS
Last year, they increased the area sown to 100ha and this year plan to put in 150ha.
"We see Subzero as a good green feed gap from October to the end of December, until we can get our sheep onto stubbles," Michael said.
"We also spray it out in January, which helps our summer weeds management, and it's left for organic matter."
Michael said they sowed the paddock back to barley after the pasture phase.
"It's too early to say how much of an effect it has on the following crop, but the yields were good," he said.
"We did have to use more fertiliser because Subzero does use nitrogen, unlike a medic pasture that fixes nitrogen. But it has quite the taproot, so it is good for the soil profile."
Michael said they also found Subzero attracted aphids, so extra insecticide was also used.
"But we have been pretty happy with how it has gone so far," he said.
"We have been nicely surprised by how much length of grazing we got off of it the past two years."
Multiple benefits behind Subzero
Mr Cook says hybrid forage brassica Subzero helps to achieve excellent livestock weight gains - up to 250 grams per head per day for lambs, with the available feed ranging from 10 megajoules of metabolisable energy per kilogram of dry matter to 14MJ ME/kgDM.
"It is also known to withstand quite cold temperatures - hence the name - but still persist through spring and summer, if there is opportune rainfall," he said.
"It even has the ability to grow through to the following winter, season dependent, whereas our other varieties only last nine months.
"Subzero is a true forage brassica type, bred for grazing and dry matter, so it certainly has a fit on the lower Yorke Peninsula in livestock operations."
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