As featured in Arable Farming Magazine
Terminator on test
by Arable Farming
Reducing the number of weed seeds lost into the field before and during harvest shows potential to cut weed burdens, reports Jane Carley.
The prospect of herbicide resistance and the loss of active ingredients point increasingly to the need to explore cultural weed control approaches.
A new season’s weed problems start with the previous harvest, as seeds are ejected in the chaff spread at the rear of the combine.
However, a number of systems have been developed to manage this issue.
H.J.Fairs and Son grows 2,000 hectares of combinable crops near Colchester, Essex.
Alongside oilseed rape, wheat and peas, the business grows specialist crops such as borage, echium, camelina, chia, quinoa and lunaria, produced for seed and for human consumption.
Farm manager Chris Barron says: “Much of our production goes straight into the food chain, so we are very limited on the chemicals we can use.
Hence our approach is to look at cultural controls – we hoe and inter-row spray for weed control, but once the crop becomes tall there is nothing that we can effectively use.
” Research suggested that the Seed Terminator might help to clean up crops at harvest and reduce the weed seed burden for the following year.
Developed in Australia, the Seed Terminator is an attachment fitted to the combine which destroys weed seeds before they can fall into the stubble and subsequently germinate.
Hammer mills It is fitted in place of the chaff spreader and uses a pair of multi-stage hammer mills which process the residue coming from the sieves.
The tungsten-coated mills are designed to crush, shear and grind seeds to a fine powder and feature stone doors and flexible flails to avoid damage from foreign objects in the crop.
There is a choice of sieves to match weed seed size for the greatest processing efficiency.
“There were no examples of the Seed Terminator for us to look at in this country, so we agreed to trial one for importer Zurn UK,” Mr Barron says.
The device was fitted by a self-employed Claas fitter to the farm’s 10.
5-metre cut JNIAB is undertaking trials of methods of harvest weed seed control (HWSC) as part of an EU-funded IWMPRAISE project.
Weed management specialist John Cussans says that seed milling has proved highly effective in countries with high populations of herbicide-resistant weeds, such as Australia and the USA.
“In those cases, the weeds in question mature at the same time as the crop.
In the UK, however, crops and many of the weeds that cause concern such as black-grass and Italian ryegrass are not in sync – in some years 95% of the seed has gone from the plant before it goes through the combine.”
This, he suggests, will reduce the effectiveness of the technique for those weeds, but it may be of value for weeds such as wild oats and brome.
“Purchasers will have to consider the balance of investment over return – in other countries the acreages and, accordingly, the combines are so large that it is a small outlay by comparison.”
But the seed mill is also a useful tool to prevent seed