Certain weeds in grain crops are developing resistance to herbicides. In some cases, this can be countered by mechanical weed control prior to and even after planting – but these measures come at a price. A solution that won an innovation award at the SIMA Show promises a system that will not only remove the weed seeds during the harvesting process but collect the weeds and chaff in a usable form.
Pérard’s VMP model is hitched alongside the combine, collecting and packaging chaff normally dispersed on to the land and not recovered. This recovery solves the problem of weeds re-growing, thereby saving time and also offering the potential for additional income through re-use of the chaff.
During harvesting, the VMP fits to the side of the combine harvester (and can be attached to various recent combine models). The system for harvesting and packaging the chaff is automated with a control console in the combine harvester’s cab, while the VMP has its own power source from an integrated diesel engine.
For road transport, the VMP unit is attached to the front in place of the header, which is then towed behind on a header trailer. Pérard is confident that after rigorous testing during the 2015 harvest season, the chaff harvester will be in production in time for the 2016 season.
The Australian solution
The Harrington Seed Destructor (HSD) is the brainchild of Western Australian farmer Ray Harrington. With assistance from the Grains Research and Development Corporation, De Bruin Engineering undertook to manufacture the unit, which has two cage mills spinning in opposite directions that grind and pulverise the seeds so that they cannot grow.
Field trials showed a 95% weed seed destruction efficiency when used during the commercial harvesting of wheat, barley and lupins. The machine was commercialised in 2013, but only a few have been sold so far, possibly because farmers are holding out for the next-generation HSD, which will apparently be incorporated into a combine harvester.
Harvesting chaff, then & now
In England, in ‘the old days’, grains were cut with a self-binder and the sheaves carted home to the farm for threshing with a stationary threshing machine. At that time, the chaff was regarded as a valuable by-product. It was stored in the stables and formed a key part of the ration for the horses when mixed with rolled oats and a generous dollop of ‘slurry’, a mixture of molasses and water.
The Pérard chaff harvester presents possibilities for a renewed appreciation of the worth of this valuable by-product.
Packaged by the harvester into relatively dense cylindrical bales the chaff can be easily collected and used for various purposes.
Fine and light, chaff is particularly useful for poultry, dairy cows and lactating sows. Chaff that has served as litter is a good biomass substrate for the production of methane because it is rich in nutrients and easily transported. The compost that results from the fermentation process in a biogas unit can then be spread as fertiliser – all of this in addition to the original idea of getting rid of the weed seeds.