What is the price of failing to control blackgrass within the rotation? Is a return to rotational ploughing cost-effective or should there be a higher percentage of spring crops in the rotation? Or what about fallowing? Is it a realistic economic option?
They are all questions growers with blackgrass problems could face in the next few years.
There is no question, however, that blackgrass continues to be a major challenge on a lot of arable units around the country. The demise of key herbicides, such as trifluralin and isoproturon, has left growers short of some valuable building blocks in creating cost-effective herbicide programmes to control blackgrass.
And the new legislation changing the basis of how crop protection products are approved at EU level could well remove more important residual herbicides in the coming years.
On top, is the ever increasing spectre of resistance to the remaining graminicides, particularly to Atlantis (mesosulfuron-methyl + iodosulfuron-methyl).
But what is the answer? New chemistry, at least in the short- to medium-term, looks unlikely. No manufacturer appears to have anything in the immediate pipeline.
It has left most experts suggesting growers have to move increasingly towards cultural controls, including utilising more spring cropping or even fallowing, potentially moving back to the plough, or delaying drilling and increasing seed rates.
But the true cost of those options on the bottom line is very difficult to estimate, which is why Farmers Weekly and Savills Research have used their unique Virtual Farm model (see panel) to put some economic values on the true cost of diminishing blackgrass control on farm returns.
The Virtual Farm model has been expanded to produce returns across the rotation for a 10-year period to help fully understand the impact of slowly, or quickly, declining chemical control, and how changes in management will benefit or diminish returns during that period.
The base model assumes we live in a perfect world and that chemical control is fully effective and there is no loss of control during the 10 years.
We have then used that model to assess the cost of a loss of chemical control in cereal crops over the 10-year period. A number of scenarios have been tested, including losses in chemical control over time.
On top of those scenarios the model also looks at the impact of changing management practices – so we have tested switching back to ploughing before second wheat crops, adding in additional spring cropping and including fallow.
For each the model calculates what the effect will be on the bottom line based on the differences in blackgrass control that each management change would bring.
Of course, to make that assessment a number of assumptions about the level of control in various crops, the amount of seed return, and effect of poor blackgrass control on yield, for example, have had to be made. But we’ve enlisted the help of renowned weed scientist, Stephen Moss from Rothamsted Research, to make sure the figures used are as accurate as possible.
So what are the results? All will be revealed at Cereals 2011. But let’s just say, it will be well worth your while in considering what you need to do to keep on top of blackgrass control in the next 10 years.More Cereals 2011 tech information.