A TARGETED two-year weed control strategy has seen Dowerin farmer Andrew Todd plant 100 per cent of his canola program to Roundup Ready (RR) varieties.
The canola program accounted for 15 per cent of Andrew's 4000 hectare cropping program and was planted to Hyola 404RR this year in an effort to combat confirmed Clethodim (Select) resistance in some paddocks with high grass weed burdens.
The innovative strategy will see paddocks fallowed or planted to brown manure (field peas) in their first year, followed by RR canola varieties in their second and then traditional wheat or barley rotations, preceded with Sakura and a paraquat-based knockdown.
Andrew believes the roration could hold the key to clean paddocks.
This season the Todd family farm had received about 100mm of rain from January to March, followed by 4.5mm in April and 34mm in May.
Despite the rainfall figures being a bit light on for this time of the year it was enough for Andrew's crops to get up and out of the ground with a reasonable level of establishment.
After what Andrew described as an effective April chemical knockdown, they starting dry seeding on April 18 (about a week earlier than usual due to the implementation of a larger cropping program).
He sowed about 55pc of his program to wheat, 20pc to barley, 5pc to field peas, 5pc to lupins and the rest to canola.
Andrew said despite having achieved one of his best knockdowns at the start of seeding, another was required mid-way through seeding, reflecting resistance problems.
He said the first dry-sown 1500ha of the family's 2013/14 seeding program went in without a knockdown and was sprayed during the second program.
Andrew said certain paddocks earmarked for canola break crops on the farm had been found to be Select-resistant, so RR was used as a strategy.
"The decision to use RRs throughout the entire program this year was a bit nerve-racking because it's such a high input crop, even compared to triazine tolerant (TT) varieties, because of the seed costs," Andrew said.
"We weren't initially going to use Pacific Seeds' Hyola 404RR on the block which had Select-resistance.
"We were going to use Canola Breeders' StatusRR but found out quite late the company wasn't able to supply the seed which was frustrating, so we put in a second order for the Hyola 404RR."
Last year the Todds sowed Hyola 404RR into a brown manured pea and lupin stubble.
The variety accounted for about 160ha of the 2012/13 500ha canola program.
"Last year the RR was planted on a different block to the TTs so it was too hard to compare the yield properly but anecdotally, the RR did yield better than the TT," Andrew said.
"And so it should have, given it had a large nitrogen reserve and additional carry-over moisture.
"We didn't put any nitrogen down on that RR canola in an effort to keep the cost of it down and it yielded about 0.7t/ha and the Cobbler TTs yielded about 0.55t/ha."
Despite the varied environmental factors which made drawing comparisons between last year's crop types quite difficult, Andrew believed his Hyola 404RR crops, which formed an integral part of his two-year weed control strategy, would come into their own this season, due to the more favourable establishment.
"Last year was fairly dry and the RR canola didn't emerge until mid June 13, even though it was planted on May 13," he said.
"We had next to no rain between May 5 and June 5 last year and the Cobbler TT was also sown into moisture in the first week of May.
"With a better rainfall year and a more timely establishment it'll be exciting to see how well the RR hybrid canola can do on a fallow."
Andrew said the combination of fallow/brown manure and RR canola formed the perfect two-pronged approach and two-year attack on the farm's grass burden.
"If it's carried out right, we should be able to get 100pc weed control from the fallow or brown manure followed by a 100pc control from the RR canola," he said.
"It's widely accepted there's a two-year turn around to target grass weed seed banks effectively.
"Science says you need two-year control but that's not withstanding economics which says you need to have some income off that paddock within that time-frame.
"A two year time period of not profiting from a particular paddock isn't acceptable for us, especially given the price of inputs.
"But by using this strategy, we can make an income from the second year while still maintaining next to full grass control.
"It's the perfect fit for RR canola."
Arguably, some growers would use a pasture rotation as their weed control option in this particular situation but that didn't fit into the Todd's program.
"This year we're running an atrazine-based fallow system which reduced the number of passes we need to do on any given paddock," Andrew said.
"Most things we do revolve around trying to combat weeds without using winter-grazed livestock.
"We're very conscious of becoming reliant on herbicide use because we've already seen what happens with 2,4-D resistant radish which is only exacerbated by exposure.
"We initially planted our first brown manure not knowing we were going to follow it up with RR canola, but as we gave it more thought we came to the realisation that to have a real impact on the grass burden in those paddocks a two-year approach was required.
"But something had to change after some of the paddocks had been continuously cropped for 20-odd years."
The Todd family also use a chaff cart at harvest and planned to grow high-yielding TT varieties again in the future, provided they fit into the rotation given the farm's patchy Select-resistance.
Andrew is also the youngest member of CBH's Grower Advisory Council (GAC). His interest in the GAC was prompted by a 2008 CBH study tour to Asia. He said it was his job to act as a grower conduit to the CBH executive. He said in recent times one of the biggest issues in his region had been growers' increased harvest capacity which seemed to advance at a faster rate than CBH's capacity to receive grain tonnes in the region.
