The question this time comes from David Cornea of Morse, Sask. David has a John Deere drill and he wants to improve tracking on side slopes. Automatic steering keeps the tractor in line, but that doesn’t help much when gravity pulls the drill off line. What can he do?
You have a few mechanical options to consider before going the GPS route to improve tracking. Disc drills track better than hoe drills on side slopes, says Patrick Chinkiwsky, sales and service rep for John Deere Seeding Group. If you have a hoe drill, John Deere has an attachment — a large coulter — than mounts in the middle of the drill to prevent side drift. “We haven’t sold many of them,” he says, but they are an option.
You also want to make sure the drill is level and that each point is sharp and at the same level of wear. Anything that pulls the drill off line on flat ground will be emphasized on side slopes.
Other factors are field shape and seeding depth. If you have nice square field, that helps. A drill tends to hold its line better when on a straight path than when working around curves. As for seeding depth, Chinkiwsky says the drill will be more susceptible to the pull of gravity when seeding shallow. You usually have good reasons to seed shallow, and keeping the drill straight on side slopes is no reason to change this practice.
In that case, you may want to take the leap to passive guidance to keep the drill in line.
John Deere has a new guidance feature, iGuide, for drills. You mount a separate GPS receiver on the drill to tell the tractor where the drill is. The tractor automatically adjusts its path when necessary to keep the drill on the path it’s supposed to follow. Other companies offer this feature. Ask your equipment dealer what’s available.
For iGuide, you have to upgrade your GPS signal to real time kinematic (RTK), which requires base stations or a subscription to an RTK tower network if you have one in your area. You also need the GreenStar 2600 display with RTK features unlocked.
iGuide will keep the drill on path on side slopes AND around curves. Before investing in iGuide, you have to figure out how much this overlap on side slopes and around curves is really costing you.
I raised the question of drill guidance on my blog (bloggn. on October 27. One reader, Greg Cochran, wrote to say they have some “fairly extreme hills” on their farm along the Saskatchewan River in northeast Saskatchewan. Yet with their 55-foot drill set for one-foot overlap, “it needs to be a relatively steep hill to actually have a miss,” he says.
Cochran then raised a new point on the topic: He wonders whether terrain compensation is really a good thing for a seed drill. Terrain compensation is built into most GPS receivers these days. If your receiver is on the roof of the tractor and you’re on a side slope, then the receiver will not be in line with the tractor’s drawbar. It will a be few inches left or right, depending on which side of the hill you’re on. You want the tractor’s path to be based on the position of the drawbar, not on the position of the receiver on the top of the cab. Terrain compensation uses sensors inside the receiver to correct for tractor tilt and