Agricultural engineer Lawrence Papworth doesn’t think there’s any magic involved in getting the best possible performance out of an air drill or air seeder.
Papworth, with the Ag Tech Centre in Lethbridge, says it’s a matter of doing a whole bunch of things right.
In the past, Papworth said, growers have tried installing seed brakes so they can run the ground and air speed a little faster. He is reluctant to recommend them.
“The idea is that the seed brake separates seed from air flow, so when the seed gets to the opener it simply falls by gravity into the trench rather than being shot into the trench by air pressure,” Papworth said.
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“It’s just a metal wire mesh screen with a deflector attached. The problem is that when the seed hits the deflector, it causes seed damage. We tested the Hooper seed brake years ago and I think Dutch Industries also had one on the market. But anything we’ve seen here was pretty crude.”
An Australian company called D-Cup Diffuser has recently applied modern engineering principles to the old seed brake concept. Papworth, who just took delivery on a set of the new devices, said the diffuser creates a cyclone effect in the seed run.
“The seed seems to spin around to lose speed. Then when it’s slow enough, it drops down into the opener. Apparently there is no seed damage.”
D-Cup inventor Dan Ryan said he designed his diffusers to relieve the air pressure so the seed and fertilizer could drop to the ground gently.
“Everyone runs higher speeds nowadays and we require high air velocity and high air volume to move large amounts of product,” he said.
“That won’t change. But the openers we have are still largely designed for the old gravity-type box feeding system. Velocity has not been factored into opener engineering.”
Ryan said the same air that is a farmer’s friend as it carries product to the opener becomes his enemy once it reaches the opener. He said most people think that only one bad thing happens when seed reaches the opener – seed bounce – but in fact, two bad things happen.
“The other thing that happens is the excess air volume forces unwanted air down into our seed trench and blows the seeds and soil around,” he said.
“The last thing we want when we’re trying to accurately place seed in the soil is a blast of air. Our goal in designing the diffuser is to siphon off the air just before the seed and fertilizer get to the opener. It spins all that extra air out the top. It’s like a miniature cyclone in there. And no moving parts.”
He said the D-Cup brings product in at whatever speed and volume the operator requires. The seed and fertilizer cycle downward, channeled by the spiraling grooves in the funnel-shaped wall of the device. As centrifugal force spins them down, they scrub off speed gently, without harming the seeds.
Most D-Cup units have only one inlet to accommodate typical air delivery systems. However, diffusers are also made with two and three inlets for farmers who keep their seed run separate from the fertilizer runs and who blend fertilizer on the go according to a prescription map.
“We’ve had this on the market here in Australia for about two years now, and so far we have about 500 drills set up with D-Cup Diffusers. They seem to be the answer to everyone’s air delivery problems,” he said.
“We’re just getting ready to start selling in North America. Once we’ve set up, I expect they will sell for about $50 US for each single inlet diffuser.”
Papworth said he received his D-Cup set from a supplier in Texas and plans to conduct lab tests this winter to see how far the devices can be pushed before they plug.
“Then we’ll do field tests this spring to see how well it works in actual seeding conditions.”
If the D-Cup Diffuser does everything it’s supposed to do, it may be the key to a better seeding job at higher speeds.
As farmers increase ground speed, they also need to increase fan speed. In a one-pass system, that means pushing more product for each foot of seed row. The air delivery system eventually hits its limit and plugs. If the plug goes undetected, farmers can be left with a lot of empty seed rows. Detecting the plug the moment it happens is the job of an airflow monitor.
The Agtron air flow monitor, manufactured in Saskatoon and now sold worldwide, is capable of detecting blockages and alerting the operator in less than one second. With thousands of units installed on Canadian prairie air systems, more producers are seeing solid crop stands without those annoying and embarrassing vacant seed rows.
Joel Neuberger of Agtron said some farmers are happy just to monitor the main runs, while others insist on every run.
“They don’t want to see a vacant seed row on their farm.”
He said seed run sensors cost $84, making it financially viable to set up an entire air drill or air seeder with monitors on every run. The sensors are available in one-inch and 1.25 inch diameters. The ART100 tube is stainless steel to prevent wear from abrasive fertilizer.
The company’s new ART100 Advanced Blockage Monitor, which sells for $876, can handle up to 120 sensors. Once this main purchase is made, each additional run is $84. The ART100 replaces the AR99 system.
“Installation is simple,” Neuberger said.
“You simply cut the hose, slip in the sensor, tighten the hose clamps and run the wire to the control box.”
The sensors use infrared light beams and optical processing to count the seeds passing through the tube. Each sensor can measure seed rates from 5,000 to 10,000,000 seeds per minute, which can help farmers analyze distribution across the seeding machine. If there is uneven distribution, the sensors can find it.
The operator selects the blockage threshold to set off the warning, which can range from five to more than 1,000 seeds per second in each sensor. The location of the blockage is displayed on the digital readout screen.
Papworth said many farmers assume that once they’ve levelled the cultivator frame, they never have to set it again.
“But that’s not the case.”
He said front wheels sink lower in soft ground and ride up in a drier year, forcing farmers to level the frame to suit the soil conditions.
Likewise, if they plant winter wheat or any other fall-seeded crops, the ground will likely be much harder than it was in the spring, so machine levelling needs to be adjusted for that. He recommended levelling both front-to-rear and left-to-right.
One of the biggest challenges facing farmers most years is getting all the seeding done within the prescribed time. Even the most careful operator can be forced to increase ground speed and crank up the air flow to get it done on time. Papworth said seed bounce is the inevitable result of too much air, not only with canola seed, but also with cereal crops.
He relates a common story: “A farmer calls his canola council agronomist to say his expensive canola seed isn’t growing. The agronomist drives out to the farm, only to see that most of the canola seed is laying on the ground.”
He said there’s not much point for farmers to increase their speed to beat a rainy weather forecast if they end up with seed on the ground.
“If you’ve got a low-disturbance disc opener, you can run up to six miles per hour. But if you’ve got a wide, high-disturbance opener, you pretty well have to keep it down below 41/2 miles per hour, regardless of what the weatherman says.”
High ground speed throws soil around and when the packer finally arrives, the soil is resting off to the side of the seed trench.
“To get around this speed issue, more farmers are installing soil levelling devices of some sort to level out the soil before the packer goes over,” Papworth said.
“The most common one we’ve seen is just a set of double discs behind the opener to throw soil back over the trench. That’s popular on machines like the Concord where they have a wide opener that throws a lot of soil, and then a rubber tire packer.”
He said harrows and rotary harrows are sometimes installed, but they can cause plugging problems. A single disc can also be effective, but it only throws soil from one side. The Haukass system of pushing soil in front of the regular packer also has a good reputation for good soil levelling, he added.
“Instead of putting a soil levelling device behind every opener, I see a lot of farmers putting them only on the seed rows that need them,” he said.
“If the front rows are getting buried by the back openers, then you might just install the leveller on those openers that make the problem. Don’t bother with the other ones if you don’t need to.”
