With new regulations now in place for the use of 2,4-D (2,4-Dichlorophenoxyacetic acid) the active ingredient in many mainstream broadleaf herbicides growers must now use a minimum of very coarse nozzles, among other strategies, to reduce spray drift and, therefore, the impact on neighbouring sensitive crops.
Northampton grower Karl Suckling has been using these very coarse nozzles for a number of years and, while he says it initially required a change in management practices, he now believes his system is set up to achieve the best response with this herbicide.
He says the key is to know the target and understand water and label rates.
"For example, if we are aiming at cotyledon radish, where the plants are very small and fine, we will increase our water rate to ensure we make contact with the small and fine plants," he says.
"However, on the flip side, if we are spraying melons, we'll use low water rates because we have a big target to hit."
As part of the Northern Agri Group (NAG), Karl and many of his neighbours participated in a spray workshop six years ago with national spray consultant Bill Gordon.
He says this was pivotal in putting everyone on the right track when it came to spray strategies.
He also updated his knowledge at another spray workshop in February this year, run jointly by NAG and the Yuna Farm Improvement Group (YFIG), with Mr Gordon again demonstrating to more than 100 growers how to achieve maximum efficacy using these very coarse, ultra coarse, and extremely coarse nozzles.
"If the conditions aren't perfect, spraying without any drift whatsoever using the finer nozzles can be a major headache," Karl says.
In fact, he believes a significant challenge facing growers right across the grainbelt is finding the right conditions to spray weeds.
This is why he says machinery set-up and using accurate label rates are critical to make the most of spray opportunities.
"We are always pushing that spray window, particularly in summer when it's so hot, which is why it's so important to have the machine set up correctly so we can achieve maximum results in the small windows of opportunity that we do get," he says.
If the conditions aren't perfect, spraying without any drift whatsoever using the finer nozzles can be a major headache.
"Even in winter time, we don't always get the right conditions to spray in it can be too windy, or too dry and the weeds are under too much stress."
Karl believes the widespread availability of mechanical weed chippers, and other non-chemical weed options, will interest growers, particularly as resistance issues become a greater hurdle to overcome.
"I don't think there will ever be a weed that is resistant to steel," he says.
But Karl doesn't think his weeds present any more of a challenge to his farming system now than the many other hurdles facing growers, such as crop diseases particularly since he now has his spraying regime set up for maximum impact.
Over the past few years, canola has taken the place of lupins as a rotational tool in the Sucklings' business. But with the rise of the fungal disease sclerotinia, it's a fine balance when it comes to the economics of disease control in what Karl describes as sub-one-tonne per hectare crops.
"We generally spray all our cereals and canola for disease at least once," he says.
"Sclerotinia is starting to become a major problem, and potentially we aren't far away from going to two spray passes.
"But that then becomes an economic juggle because we don't know what the yield result will be when we have to make the spray decisions.
"In some years, the canola yield is less than 1t/ha and you can't economically spray two passes on a crop with that yield result."
Finding a sclerotinia resistance gene for canola should be an urgent research priority, Karl says.
"Hopefully there will be some genetics that come out of Canada, given that they already have some pretty good breeding material for canola resistance to sclerotinia there," he says.
Canola is a critical part of the Sucklings' business, and this year they will plant 2300 hectares of canola.
"We grow all genetically modified canola up here because, since it is a hybrid plant, it can handle a lot more adverse conditions, particularly if we get thrown a hot two weeks early in the program," Karl says.
"GM canola still works economically in this area, even in sub-one-tonne/ha crops."
The business tried some triazine-tolerant canola in 2017, but the family couldn't achieve the same weed control as when they planted a GM variety.
"The reason we grow canola is to clean things up for our cereals, and that's why we are sticking with the GM varieties," Karl says.
The lack of profitability in a lupin crop on their soil types has seen them phase this grain out of the business.
In stark contrast, canola has been their best gross margin crop for many years.
The Sucklings have grown Albus lupins (human consumption) previously, but a lack of local market options makes the freight very expensive.
GM canola still works economically in this area, even in sub-one-tonne/ha crops.
"We haven't written them off entirely, but if we don't receive rain by the 10th May, they will be taken out of the program," Karl says
Apart from weeds and disease control, the most significant factor to affect yields in the region is early season heat stress.
In Northampton, crops can often experience temperatures above 35 degrees Celsius in May, sending them out into head too early and severely reducing their yield potential.
Unlike the vast majority of the grain growing regions looking for an early start to their seeding programs, Karl is always cautious of going in too early.
An early crop could mean the plant is fast-tracked in the autumn and early winter warmer conditions and not allowed enough time to tiller properly.
Mainstream wheat varieties can be out in ear in the second week in June if planted before May 10.
"Our worst financial years were in 2012, 2013 and 2014 and, while they weren't bad rainfall years, we had very warm winter weather," Karl says.
"In fact, in 2014, I remember we had two weeks of above-30-degree Celsius temperatures which turned a 3.5t/ha wheat crop into a 1t/ha crop."
Karl says many of the mainstream wheat varieties currently available don't take into account this early heat stress.
"Most winter and spring wheat varieties are designed to pick up heat units quickly, but quite opposed to what growers down south are looking for, we need to slow them up so they don't come out in ear so quickly," he says.