SASKATOON – Precise plant density is an agronomic factor still beyond the control of small grain and oilseed farmers.
Corn growers in the United States mastered it decades ago, but for the rest of the farming community, it remains a problem. Producers can do everything exactly according to recommendations and still end up with erratic plant counts from row to row and within any given row.
It’s a significant economic concern, said Bill Baker, president of Agtron Enterprises, the Saskatoon company that develops and manufactures electronic instruments for farmers.
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He said uniform plant distribution makes better use of soil moisture, sunlight and nutrients.
Baker divides the issue into two categories. There is the typical uneven distribution of seed that producers accept as normal when their air seeder is functioning properly. Then there’s the total loss of plant population when a run or a tower becomes plugged.
“If you have a plugged run, every foot of unseeded row represents lost investment on your fertilizer, diesel, time and overall investment in your farm,” Baker said.
“If you have a plugged tower with six runs, that financial loss multiplies. Not only that, here’s the worst part: the fertilizer you’re paying for but not using begins working against you because it feeds the weeds instead of your crop. Now you have to spend extra time and money on weed control. That just adds insult to injury.”
It’s a problem producers seldom discuss because they believe there’s little that can be done about it.
The size of a financial loss is open to speculation. Baker wanted to get a handle on it, so in 2003 he approached Manitoba Agriculture for help in crunching some numbers.
Together, they tried to figure out how much money might be put back into a producer’s pocket if he could detect a blockage on an individual seed run and also on a six-run tower. The exercise was run with hypothetical fields of 160 acres of canola and wheat. All input values and crop prices were provided by Manitoba Agriculture. The results were startling.
The first quarter section field was canola. The calculated financial loss from a single blocked run was $970. On a quarter section of wheat, a single blocked run cost $813.
A blocked tower on a quarter section caused $5,803 in losses for canola and $4,868 for wheat.
Baker said seed damage due to high air flow is another economic factor that producers don’t always consider.
“Guys will crank up the air above the recommended rates to prevent blocking when they’re doing things like lentils and chickpeas and even field peas.
“But when you’re working with delicate seeds like these where you crack the skin and injure the seeds, you’ve got to keep the air down to recommended rates. You can cause a lot of seed damage and that means seeds that do not grow into productive plants.
“The other thing with high air flow is you bounce so many seeds out of the seed trench. The best solution is to keep the air flow within the recommendations and carefully monitor for blockages.”
The target seed count for wheat in typical Canadian prairie conditions is one million seeds per acre. Two factors can drive that number as low as 500,000 seeds per acre or as high as 1.5 million seeds per acre.
The first part of the problem is traced to variations in seed moisture and density and thus seed weight. Baker said this has been the driving factor behind many of his AgTron innovations.
“The density of each seed within a seed batch can vary up to 25 percent. That means the difference in seed weight between the lightest seed and the heaviest seed within any given batch can be up to 25 percent,” he said.
“Now, consider that every air seeder manufacturer instructs their clients to calibrate the air delivery system according to seed weight. Air seeder calibrations are all based on pounds per acre. It’s convenient. It’s tradition. That’s just the way it’s always been done.
“But if the number of seeds per pound varies by 25 percent, then your pound per acre number is misleading. You’re measuring the wrong thing. You’re weighing pound of seed when you should be counting individual seeds. Pounds per acre is a meaningless number.”
Baker said the other half of the problem is the air flow system. Even when it’s set up by the book, it’s really not perfect.
“Your seed metering system itself can be off by as much as 25 percent, even when you’ve gone to great lengths to follow the calibration procedures.
“Put these two factors together and it’s easy to see that the end result can be a huge variability in the plant population within a field. It really makes a joke out of that term precision farming. There’s nothing precise about a 50 percent error.”
In response to this situation, Agtron has concentrated research and development resources on three areas: counting seeds in the run; a controller compliant with the International Standards Organization to manage a wide range of functions; and specific plant population controls.
The basic Agtron blockage monitor that came to market a decade ago has been upgraded so it can now count individual seeds and translate that number into seeds per acre.
It still gives the operator an immediate warning when there is a full or partial blockage, but more importantly, the screen now gives the operator an accurate reading of how many individual seeds per acre are going into the ground. It gives this reading regardless of seed density or seed weight.
“We count the seeds optically, so the information doesn’t depend on seed size or seed weight. Your monitor gives you an exact number of seeds per acre.”
The ART-100 monitor that only checks for blockages now sells for $1,400 including the cab console. The ART-120 advanced monitor that counts the number of seeds per acre sells for $1,700 including cab console.
Do-everything controller
The next step in Baker’s quest is a new ISO 11783 compliant controller that can handle all field functions within one unit, including GPS and mapping.
“We’ve got shortcuts for all your main functions. This business of bouncing down the field in your tractor trying to navigate through a menu trying to find a function, that isn’t my cup of tea. So we have 10 shortcut keys and six toggle switches all assignable to main functions. You can go directly to each function without even looking.
“Everything in the D3 is fully ISO 11783 compliant and fully compatible with other ISOBUS manufacturers. But there’s nothing in the ISO rules that requires us to make things difficult for the operator, so we make things easy.”
Baker said the D3 has other features that go beyond what’s required for ISO certification. With a 100 amp operating capacity and a 150 amp surge capacity, the D3 is capable of handling more electrical current than other controllers.
This means the one controller can look after a wider range of solenoids, electric clutches, fans, lights and other devices. It also means greater holding power for electric clutches, plus electric motors can achieve more torque and higher rpm.
Another unique feature of the D3 is that it operates over a wide voltage range, with full efficiency and accuracy from 10 to 22 volts.
“If the tractor’s alternator is failing, the voltage drops below 12 volts. If the regulator has a short, the system might put out more than 20 volts. Either way, we want the controller to continue functioning without interruption or a crash. We don’t want our unit to misbehave just because the tractor misbehaves.”
The safety margin continues throughout the D3 engineering.
“Each pin in our module handles 13 amps, compared to five amps for most other modules. When you overheat pins, they start to corrode on the surface and the plastic holders they are moulded into start to deteriorate. They become unstable, they have increased resistance and transmit the wrong signals or they just won’t function at all.”
Built according to ISO specifications, the D3 is sealed so water cannot affect internal components. D3 modules are already loaded and there are 100 external I/O pins.
Baker said a limited number of the D3 prototypes have been field tested by prairie farmers and more will be tested in 2007. He expects it to be available in late 2007.
It’s one thing to count how many seeds go down per acre.
It’s another to actually control the number of seeds per acre and determine where they go.
Row spacing gives producers one dimension of that control. But the other dimension, precise seed spacing within each row, is still not possible for small grain and oilseed growers.
Corn growers accomplish singulation and precise seed spacing within the row using large, spinning drums to single out each corn seed. However, that technology is not easily transferable to other types of farming.
Baker said his next step will be the biggest technological challenge of all. Placing each seed in an exact position in the seed row is closer to reality.
“Right now, we can correctly get the average (seed placement) across the width of the toolbar. As for exact spacing within the row like the corn growers get, that’s still a ways off for us. But it’s coming.”
He said the Horsch Anderson drill built in South Dakota is a good example of state-of-the-art seed control. The drill uses an electric seed meter control system designed and built by Agtron.
“The Population Sensor counts the seeds, then factors in ground speed, row spacing and frame width. That determines plant populations.
“As it measures the number of seeds going into the ground, it adjusts the speed of the electric motors that drive the metering units. We use an electric motor because it’s the only thing that reacts quickly to the signals. Hydraulics or mechanical systems are far too slow.
“One thing that will appeal to a lot of people is the fact that once everything is set up and functioning, you no longer need to take time to calibrate your air seeder. Simply punch in the plant population you want and start seeding.”
Once the new D3 controller is ready for sale, Baker will integrate it into an overall seeding management
system that includes the Population Sensor.
“When it’s all working together, we’ll need some kind of snappy name. For now, I think we’ll call it Agtron Drill Manager 3.
“Our aim is not to make this an aftermarket system that you plug into your present air seeder. It’s going to be an OEM product aimed at manufacturers so they can give their clients the best possible control of their seeding operation.”
