Field notes on northern canola
The Aisthorpe family at Somerset, outside Roma, had side-by-side contours of wheat on wheat and wheat following canola, where they needed one less spray of Roundup for fallow weed control. As a result they reported a $10/ha saving.
While the yield in the overall 3.2 t/ha crop favoured wheat on wheat by about 100 kg, the wheat on canola ground had 2 per cent more protein, according to Scott Cawley, Department of Primary Industries agronomist at Roma.
"We think one factor in that is that canola residue breaks down faster than wheat. We did a pre-plant test for nitrogen for this year's wheat rotation and found slightly more N following canola — 42 kg/ha, compared to 28 kg/ha after wheat."
Mr Cawley and CSIRO agronomist Mike Robertson coordinate linkages between the GRDC-supported canola and Western Farming Systems (WFS) projects to allow collaborating farmers to test their ideas in conjunction with researchers. Canola's success in trials at the WFS site at Nindigully has contributed considerably to encouraging growers in the Maranoa and Balonne districts (around Roma and St George, respectively) to try commercial areas of the crop.
Match your planting date to variety
According to Mr Cawley, while details of all trials for last season haven't been fully assessed, the main lesson for canola growers from the 1999 season is the importance of matching planting date by variety.
"Yield appears to drop markedly off the shoulder of May, and we are tending to think mid-April to the third week in May is about right for the area between Roma and the border," he says.
"Between us all we tried a whole range of varieties in 1999, and the feeling is that the medium-quicks are the way to go. There are a couple of very quick varieties from Pacific Seeds and Dovuro that may suit the market niche that is willing to sacrifice some yield potential to achieve a plant later in the season.
"From 1998 results, and preliminary ones for 1999, the idea would seem to be the same as with wheat — don't have all your eggs in one basket, with just one variety and one maturity time. Some canola crops were frosted in 1999, and perhaps we need to calculate a variety by frost interaction, of flowering date by frost vulnerability; Mike Robertson's GRDC project is looking at that."
What about marginal moisture?
Mr Cawley says grower determination to plant per calendar in 1999, in a situation of marginal moisture, created some establishment problems, possibly worsened in the north by growers planting zero-till into rougher seedbeds.
The answer to that could be to boost seeding rates in zero-till situations, or to incorporate a couple of extra soil workings. One of those could involve pre-plant fertiliser, if that was a grower's strategy.
Pacific Seeds area manager Maree Crawford said the company's approach to developing canola varieties for the northern region has involved identifying the best existing performing lines from growers' paddocks and refining them for regional conditions.
"We rely equally on our own research facilities and on independent results from farmers' paddocks," she says. "Pacific Seeds will have three medium-quick varieties and two super-quicks — 58-60 days to flowering — available for planting in the year 2000."
Region North, South, West