That’s about to be fixed by a team of overseas specialists returning for another round of workshops around the nation to help growers load more grain and seed into their silos.
The workshops organised by the Foundation for Arable Research (FAR) end today in Central Canterbury after stops in Wairarapa, Waikato, Manawatu, South Canterbury and North Otago and Mid Canterbury.
Workshops were increased after the success of a Mid Canterbury event last year.
Selected farmers brought their own harvesters to each workshop so the experts could make adjustments and fine-tune machinery so they were running efficiently.
Experts providing advice for their own harvester brands included Kassie van der Westhuizen for John Deere, Brett Asphar for Case and Claas and Murray Skayman, from Canada, for New Holland and Case.
They will return in February during the harvest to gauge how well adjustments are performing in the field.
FAR technology manager Chris Smith said crops worth potentially hundreds of dollars are failing to be harvested across the country.
"The guys we’ve got coming over from Western Australia reckon in 2021-22 they did some testing and there was $320 million of grain thrown out the back of machines by extrapolating the work they had done. Obviously we are not the same scale as those guys, but there is money to be saved and not only that, once the crop has gone out the back of the machine it becomes a weed as well to become another problem."
He said a drum and concave — a spinning round grid with mesh on the outside — failing to be square to each other in a harvester could end up becoming an expensive problem for growers.
"They can be pushed out by a big lump going through and 2mm out on one side back or forth or up or down can be up to about 5 tonnes an hour of output loss so it’s quite phenomenal. It gives you an idea of the easy savings to be made and it’s definitely worthwhile doing that sort of stuff."
When the crop goes into the harvester they have different mechanisms including a drum or rotor which brushes against the concave. Adjustments can be made to the distance between them, and growers can monitor their speed to open up the gap in the concave so the straw was not being broken too much and preventing the grain from falling out.
Most crop farmers were mechanically minded and it was probably a lack of awareness of machinery gradually getting out of sync over the harvest during a busy period of the cropping season.
Making sure the settings were equal with the other side so the gap was even and the mechanical lever was on the correct setting made a difference, while the condition of fans should also be checked and harvester knives for sharpness.
Mr Smith said now was the time to tune harvesters. Growers often got dealers to do a winter service or did it themselves.
He said the specialists were not trying to teach growers how to "suck eggs", but were just making them and dealers aware of these points.
"When we had guys last year who were opening up the concaves they were making up to 30% in fuel savings than what they would normally use and we had one grower who went from 20ha a day to 30ha a day of barley last year by opening up the machine more and allowing the crop to go through quicker and more efficiently ... A Southland grower said he saved 70 hours off his harvest by changing the settings which they told him to do. At the time he reckoned it was about $1000 an hour."
He said another grower was found to only be losing about 1% off the crop "out the back" of the harvester so he could increase his speed and work out the optimal speed when losses increased.
This calculation allowed him to increase his harvesting speed from about 3km/hr to 4.5km/hr.
Mr Smith said they would focus on losses again for small seed crops, but also seed quality as wastage could be as much as 25% when it went through a dressing plant.
"Basically one in four trucks could be just waste, so by getting that percentage of dirty sample cleaner it’s better for the industry as a whole, with less waste carted around and less space taken up. People pay for the weight in rather than the weight out so obviously the seed-dressing plants are paying for it and also have to get rid of this rubbish as well."
This follows increasing dressing losses in ryegrass and other small seed crops being reported by seed cleaners.
Methven-based Norwest Seed Processing spokesman Allan Lill said losses were often as high as 30% and at this level were becoming an environmental issue.
“These losses need to be addressed in the field and not in a commercial cleaning operation."
Seed-dressing losses are thought to have increased the past 10 years because of larger, more automated combine harvesters relying on electronic controls and readings which may not be accurately calibrated.
Seed Industry Research Centre technical committee manager Phil Rolston said data collected from 147 seed lines at another Mid-Canterbury seed-dressing plant showed just over one third of them had more than 20% dressing loss between 2022 to 2024, with the highest at 51.6%.
Mr Smith said groups had been set up for growers so they could talk between themselves about harvester tuning and share problems and troubleshooting suggestions.
