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Three Considerations For Switching Seed Carts

There are a number of ways to speed up seed cart refills during seeding, but what if you could also reduce the number of stops you have to make in a day? How many more acres could you cover? Changing to a larger capacity cart can keep you going for longer stretches.

“For each stop you don’t have to make, that’s more time spent seeding,” says Blaine Metzger, a project manager at the Alberta Ag Tech Centre. “(Larger tanks) are definitely more efficient.” So it’s an option worth considering, particularly if a producer intends to expand the number of seeded acres and wants to minimize investment in new equipment. It might eliminate the need to purchase a wider toolbar but still cover more acres in a day.


But before going out and buying a larger cart, there are a few things to consider. First, does your tractor have enough muscle to pull that extra weight around the field? Although the Ag Tech Centre hasn’t conducted draft tests on carts in several years, Metzger says the last cart test he can remember was on a 160 bushel tank that required 40 horsepower to pull.

But those numbers can vary widely. Metzger doesn’t think just using that horsepower to capacity ratio as a rule of thumb will always work. “There are a number of factors that can affect it,” he says. Those include the type of terrain, such as hilly versus level ground, soil type and moisture conditions. All of these can vary the amount of rolling resistance and change the horsepower requirement.


Next, the distribution system used by the cart (type A, B or C) has to match the piping on the toolbar. On type A systems, seed is metered into a single primary line that runs from the cart to primary splitters on the tool bar. Seed flow is then distributed to secondary lines which lead to another set of splitters. From there, individual lines run to the openers.

Type B systems meter seed into several primary lines, which run to a single series of splitters, dividing seed flow into lines running to openers. Type C systems meter seed directly into dedicated lines that runs all the way from the meter to the opener, without ever passing through a splitter. The cart and toolbar have to be compatible.

On a type B, some primary lines can be blocked off if the tank has more than the toolbar needs. “If you have plug one or two off, it really doesn’t affect anything,” says Metzger. “Just put a plug in right at the cart.” The meter gate can be closed to prevent seed from being fed into the unused primary lines.

Garth Massie of Morris Industries, an air seeder manufacturer, says the type B system Morris uses can be easily adapted to changes in drill width. “It is relatively simple to adapt our air cart to a different sized drill,” he says. It is just a matter of matching the number of metering wheels (the width of the meter) to the number of primary lines to ensure even seed distribution.

Type C systems may be the simplest to deal with. “That’s the easiest kind of cart to swap. You don’t have to worry about manifolds. Each line going to the opener has its own meter. There should be a gate at each meter that they (farmers) can just shut the flow off,” says Metzger

But there is another factor to consider when it comes to finding a compatible cart. “You need to match the cart to the implement based on whether you are using a single, double or triple shoot opener,” adds Metzger. Some carts are capable of operating in one, two or even all three of those modes, but others aren’t.


Fan speed will also be something producers need to fine- tune when putting a new cart on a toolbar. Putting a small cart on a larger toolbar may not work, because the fan may not be able to move product out to all the additional openers. Going the other way, however, the fan will have excess capacity. So, it may need to be slowed down.

But when changing fan speeds by a large amount, Metzger says that could cause a problem when adjusting meter settings on some cart designs. Producers should make sure the cart actually metres out as much product as required when air pressure is applied. With some meter designs, product flow can be reduced due to a back flow of air into the tank. Simply increasing metre rates to compensate can correct the problem.

Rob Fagnou of Bourgault, another air seeder manufacturer, agrees producers switching carts need to pay attention to the fan. “If the operator is changing from single to double shoot, considering very high rates of product, or is putting a much larger seeding implement on a tank that was previously matched up with a smaller one, possible changes to the air supply should be investigated,” he says. “In any case, the operator will need to refer to a new set of recommended air speed charts in his operator’s manual for the new-sized seeding implement.”

And in order to ensure the cart’s metering system is adapted to the new toolbar size, changing sprockets may also be necessary. Fagnou says Bourgault’s type A design matches a metering sprocket to the size of the toolbar the tank is attached to. “The implement sizing sprocket is designed to keep the rate chart the same throughout the range of implement widths,” he says.

Finally, the drill’s monitor will have to be adjusted to account for the new drill width.

In the end, this may be an occasion when a conversation with the service department at the local dealer may help save time and ensure the change goes smoothly. At the very least, make sure you read the owner’s manual!


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About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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