Seeding between rows of stubble gives your crop the benefits of zero-till and the warmer soils you’d get from tilled land. To do this, you need an accurate GPS signal and tools to keep the implement — not just the tractor — in line

Crops that sprout nestled in crop stubble enjoy a number of benefits. Stubble not only traps snow and returns organic matter back to the soil, but it can also create a microclimate at the soil level that is more beneficial to seedling growth. Just eight to 12 inches of stubble traps snow, slows wind speed and warms seedlings enough to translate into a 10 to 15 per cent yield boost in the fall. It follows then, that there’d be benefits to placing seed in between stubble rows.

The secret benefit to seeding between the rows, at least in part, is increased water use efficiency, says Herb Cutforth, an agrometeorologist and soil physicist with Agriculture and Agri-Food Canada at Swift Current’s Semiarid Prairie Agricultural Research Centre (SPARC). Anything that can slow wind also slows the drying process of both the soil and the seedling itself. This conserves water — the most limiting factor for production in the Brown and Dark Brown Soil Zones.

Cutforth’s research has focused solely on the effect of the microclimate created at soil level when stubble is present, not necessarily on the benefits of placing seed between stubble rows, but the connection between the two is an easy one. “Seeding between stubble rows with a degree of accuracy has two benefits: one, the seed is placed in a more favourable seed bed and, two, more stubble is conserved and left standing during the seeding process.”

Conservation of stubble is a theme of Cutforth’s work. “We’ve done plenty of work with cereal stubble, but as canola acres increase, we need to look at that, too,” he says. “Canola stubble is far more fragile than cereal stubble. If you run over canola stubble it doesn’t bounce back like cereal stubble.”

A SPARC research project beginning this spring will use SeedMaster’s Smart Hitch on a hoe drill to minimize “drill drift” across stubble rows, maximizing the amount of canola stubble left standing after seeding. Cutforth will measure how the standing canola stubble changes the microclimate near the soil surface and how these changes affect subsequent pulse and cereal crops. He’s excited about the added between-row accuracy of the Smart Hitch, but adds that combining precision guidance to the mix would be ideal.

The Smart Hitch doesn’t incorporate a GPS signal directly, relying on the tractor’s auto steer to keep it on target, but it does hydraulically steer the seeder between stubble rows. Norbert Beaujot, owner and president of SeedMaster, has been using the Smart Hitch for nearly 10 years now. “When I started this, I had no GPS at all,” Beaujot says.

He designed the Smart Hitch to work hydraulically and mechanically. Sensor discs ride on each side of a row of last year’s furrow. It senses the stubble rows and when one disc drops lower than the other, the hydraulics kick in and push the seeder back between the rows. The hitch, set up on SeedMaster drills only, has caught on and is now installed on half the seeders SeedMaster sells.

“The seed ends up in a blacker, cleaner seed bed, which is usually a warmer seed bed giving the crop a great start. The benefits spill over to later in the season, too, in that we can harvest faster and more efficiently because we cut taller, knowing we can seed between the rows come spring,” Beaujot adds.

“We now use GPS and auto steer on all our tractors,” he says. “We use the StarFire 2 and pay for the corrected signal, which gives us up to six inch accuracy, but that alone is not enough to accurately seed between the rows.”

Most farmers using the Smart Hitch seed are using 12-inch spacing, and that works fine, though Beaujot is moving to 14-inch spacing for other agronomic reasons unrelated to between row accuracy. “The Smart Hitch works well on all SeedMaster spacings from 10 inches to 14 inches.”

After years of use incorporating auto steer, Beaujot says the stubble rows get more and more straight, making it easier every year. “Auto steer and the Smart Hitch are a great combination,” he says.

What you need to seed between rows WHAT YOU’LL NEED: A SEED MASTER DRILL, WITH THE SMART HITCH INSTALLED COST: SMART HITCH RUNS ABOUT $4,000 PLUS INSTALLATION OTHER APPLICATIONS: SEED MASTER INTRODUCED THE SMART LINK LAST YEAR AND IT WILL BE AVAILABLE COMMERCIALLY THIS SPRING. THE SMART LINK USES A RECEIVER TO COMMUNICATE WITH THE TRACTOR’S AUTO STEERING SYSTEM ALLOWING THE SMART HITCH TO DO ITS JOB MORE EFFECTIVELY THROUGH SMALL ADJUSTMENTS TO THE TRACTOR’S PATH. THE SMART LINK MAKES USE OF THE MORE AFFORDABLE GPS SIGNALS, NOT RTK. WHAT YOU’LL NEED: TRIMBLE’S AUTOPILOT DISPLAY, RECEIVER AND NAVIGATION CONTROLLER, FMX DISPLAY WITH TWO BUILT IN RECEIVERS, AND TRUETRACKER OR TRUEGUIDE. WITH TRUETRACKER YOU’LL ALSO NEED EITHER A HYDRAULIC OR GROUND-ENGAGED STEERING MECHANISM COST: IT DEPENDS ON WHAT YOU’VE ALREADY GOT IN THE CAB, BUT A COMPLETE SET UP WILL RUN SOMEWHERE FROM US$12,000 TO US$20,000 PLUS HARDWARE AND INSTALLATION

Here is a sample of the equipment guidance system you need to seed between rows:

JOHN DEERE IGUIDE

SEEDMASTER

TRIMBLE TRUETRACKER AND TRUEGUIDE

ACCURACY BOOSTS YIELDS

Achieving sub-inch accuracy with seeding implements is a goal for many farmers. Matt Hesse, Autopilot business segment sales manager for Trimble Navigation, says farmers in Australia are pushing for accuracy to overcome implement slippage on slopes. “On a 40-foot planter, you could have up to 12 inches of slip,” he says. “That’s too much.” Achieving greater accuracy means fewer misses and overlaps, both of which either reduce yield or waste seed and inputs.

Solving this problem depends on having the equipment determine the tractors’ path, and not the other way around. Enter Trimble’s TrueTracker, a GPS-enabled steering system mounted directly on a seeder or planter. Using either a steerable axle or a ground-engagement system, the TrueTracker works independently of the tractor’s Autopilot guidance. “When you’re moving along rough terrain, knolls or through muddy spots, the seeder hits that same terrain some 30, 40 or even 50 feet behind the tractor. TrueTracker ensures you’ve got the same accuracy that far behind,” Hesse says.

Combine this with the sub-inch accuracy and you will see big benefits in certain applications. Potato growers are docked for split, broken or nicked potatoes. Using sub-inch accuracy at both planting and harvest resulted in a 13 per cent increase in potato quality in one Trimble study. Another study looked at corn farmers in the U. S. who are using strip till applications to lay down fertilizer prior to planting. If seed was placed right over this band, the field yielded 30 bushels per acre more than if seed was eight inches to either side of the band. “This is typical of what happens,” Hesse says.

GETTING MORE ACCURATE

Accuracy is a great thing, so it seems. But you’re only as accurate as your signal. Luckily for more and more farmers, RTK tower networks are sprouting all over the landscape, with plans from several equipment dealerships to expand those networks this year. That makes RTK more affordable. (For more on this, read Jay Whetter’s article on this page.)

Fixed RTK base stations mean repeatable lines, year over year, and increased overall accuracy. “GPS accuracy, even with an RTK signal, is only accurate to the receiver,” says Andrew Abraham, John Deere’s AMS regional specialist for Western Canada. “From there, vehicle set up, such as tire pressure, ballast and even the type of implement behind the tractor is going affect your accuracy. And then to truly get sub-inch accuracy you need some other steering or guidance on the implement,” he says.

John Deere’s iGuide product seeks to achieve just that. “We put a receiver on the implement itself,” Abraham says, which sends a signal back to the tractor’s steering and adjusts it accordingly. “The tractor will steer off-line to keep the implement on line, compensating for the implement’s movement,” he says. In trials performed last year, Abraham says they did achieve between-row seeding, but in fairness he adds that the terrain was relatively unchallenging. With iGuide disabled, using RTK only, they were able to seed between the rows in flat terrain.

As for applications in Western Canada, where potatoes and corn are grown but are not the norm, Hesse is excited about Trimble’s newest offering, TrueGuide. “Guidance and steering are two very different things,” he says. “Implement steering, such as what TrueTracker offers, is active and independent of the tractor’s auto steer mechanism. Guidance is passive.”

Similarly to iGuide, the TrueGuide option, being launched this May, is a passive system that “tells” the tractor when the implement is moving sideways off line and adjusts the tractor’s path accordingly. “There is a trade-off in accuracy, certainly, but the TrueGuide option is less expensive (than TrueTracker) and will offer increased accuracy than auto steer alone,” Hesse says. He sees it as a great option in relatively flat terrain, something the Canadian Prairies has in spades.

Lyndsey Smith is a field editor for Farm Business Communications.

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