FARMERS with mixed livestock and cropping enterprises can add value to their business as well as get a good weed break through the strategic use of pasture or fodder break crop.
Annieka Paridaen, Southern Farming Systems (SFS), said providing pasture or fodder fitted in with the overall system, it could add value to the farm along with the weed control benefits.
She said pastures could be especially valuable to mixed farmers in high rainfall zones where weed resistance had built up quickly.
“There’s a long growing season and a long spring, which is fantastic, but it also allows multiple germinations of weeds,” Ms Paridaen said, speaking at a recent Grains Research and Development Corporation (GRDC) update in Ballarat, Victoria.
“It can often be cold and wet over winter, especially in southern and elevated areas, meaning suboptimal spraying conditions.”
While she said the natural fit was to graze paddocks with pastures, Ms Paridaen said a system could also be fitted for solely cropping farmers.
“You have a look at markets nearby and perhaps sell some fodder to dairy farmers in the area, and use that hay crop as the break.”
Ms Paridaen said crop choices could be used as part of an integrated weed management (IWM) strategy.
“A lot of IWM is about rotating herbicides, but it is also about crop choice.”
She said farmers had got the hang of controlling weeds in the first half of the season, but in the second half, when there were issues spraying, weeds could still become a problem.
“In the second half of the year, when we struggle to get on the paddocks, we are still falling on our faces and that means the seed bank is often replenished by the late emerging weeds.
“The chemistry we have available in crop is not effective and that has the double whammy that we may be selecting for late germinating weeds.”
This is where she said fodder crops could be especially useful in cutting weed numbers.
The critical part, according to Ms Paridaen, is using the fodder crop correctly.
“When you are either cutting a crop for fodder or working it back in, it's critical to get the timing right.
“If you push for extra hay yield and cut it late and the weeds have already set seed, then you’ve missed the point.”
Ms Paridaen said, however, this phase need not be a ‘wasted’ year within the rotation, even if hay yields were lighter.
“It can still be profitable with hay or with livestock if done right.”
And the cut in weed numbers can be spectacular.
“In one year under balansa clover, we managed to bring annual ryegrass numbers down from 180 plants a square metre to 15, an 85 per cent reduction.
“With a two-year break this figure is reduced to five plants.”
Ms Paridaen said the differing break crops all offered different pros and cons.
“Some will offer good early competition and early grazing, while others will deliver more in terms of spring fodder conservation, while the legumes obviously fix nitrogen.
“Farmers have to choose what will suit their system best, considering things like what are the major weed issues and how much do they want to spend.
“For wild radish, clover works very well, while lucerne can make good hay, but the crops following it can struggle, farmers will be faced with all these types of decisions.”
Ms Paridaen said while strict no-tillers disliked the thought of livestock on cropping paddocks, due to the threat of compaction, most studies showed only minimal compaction in the very top of the soil from livestock.
“It has rarely been an issue for subsequent crops.
“It is shallow compaction and is rectified by natural processes and tillage.”