Conventional vs Independent

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In the world of hoe style drills there are two basic types: conventional and independent. 

Conventional drills have shanks mounted straight to a solid frame with gang packers mounted on the rear of the machine. These units have a single depth control for the entire machine. 

Independent drills have a row unit that includes shank(s) and a packer tire mounted to the frame. This style of drill relies on the packer tire to set and maintain depth; each row unit contours the ground independent of the movement of the frame. 

 

 

Pros:

Conventional machines are praised for being simple, easy to maintain and are typically at a lower purchase price. These machines can also usually tolerate a higher seeding speed. The gang packers being in a single rank on the rear of the machine can mask some uneven soil thrown in the forward ranks of the machine. Trash flow in the cultivator shank style of conventional drill is typically better than many dual shank independent drills. Conventional drills also have many more options available for openers and packer tires. For example, a new Bourgault 5810 AHD comes standard with Quick-Change adapters but can fit any aftermarket opener. For packer tires, they have six different options across three different materials (Bourgault.com). 

Independent machines maintain a much more consistent depth across the working width because each row unit depends on the packer tire to set and maintain depth. The relationship between the opener and packer tire is consistent; as the row unit works up knolls and through depressions, the opener stays at the predetermined depth setting. Each row unit can also be adjusted independently of one another. This can be advantageous if several different openers want to be tested on the same machine. They may interact with the soil differently leading to a different seed depth on the same setting. Individual depth settings on each row unit can offset this. 

Cons:

The main drawback to a conventional machine is that with the shanks being mounted to a solid frame, each row is not able to contour the ground leading to an inconsistency in seeding depth. Shanks going over the knoll of a hill will get shallower and shanks coming up from a depression will dig deeper. This can be very problematic in undulating terrain. In a 2020 study at Michigan State University, a planter was shown to increase seed depth uniformity by 60% compared to a conventional drill (MSU, 2020). Even though this was a planter and not an independent drill, the mechanism of depth control is much the same and similar results can be assumed. The main takeaway should be that there is room for improvement on the conventional drill system. 

Even though independent drills are superior in maintaining depth, they do have their drawbacks. With each row unit having its own packer tire, excessive soil throw can be much more noticeable. This usually means a slower seeding speed compared to their conventional counterparts. More moving parts, mainly hydraulics and bushings, means added cost in maintenance and potential downtime for repairs. They also come at a higher upfront cost to purchase. More accurate depth control also comes with a more complicated series of steps to setting depth. Additionally, because each row is individual, depth settings may be different throughout the machine. This can take more time during seeding if the operator wants to fine-tune their machine. As each row depends on hydraulics to control the row unit, these drills have higher hydraulic requirements from the tractor as well. Even though each row unit can be set individually if the producer wants to experiment with different openers, the independent drills tend to have less options than conventional drills. Part of this is due to the higher number of moving parts. Some independent drill brands have design boxes that aftermarket companies have to stay within, thus limiting what can be offered. There are also less packer tire options. A new Bourgault 3330SE only has 4 packer options, varying in width and shape (Bourgault.com).

Which Is Right For You?

The ultimate question when comparing these two types of hoe drill is, which is right for your farm? 

Upfront cost is the first point to tackle. Can your farm afford the more costly independent drill? Will the increased depth accuracy of the independent drill lead to more monetary return to make up the difference in cost over a conventional drill? Maintenance costs down the road should be considered as well. On top of the regular maintenance to conventional machines, hoses, bearings and openers, independent machines also come with hydraulic hoses and bushings. Can the farm take these extra annual costs? Can the farm accommodate more downtime in spring if these parts become an issue? With the added hydraulics, the tractor needs to have the capacity to run them. Is your current tractor capable? Or, will the purchase of an independent drill also lead to the purchase of a new tractor? This can drastically change the total cost. After the costs of the machine, your farm’s environment needs to be taken into account. Is your land undulating enough to warrant the need for a more contouring machine? Some areas of the prairies arguably don’t need the extra contouring with how flat they can be. Does your area get enough moisture to compensate for inconsistent depth? Moisture is the most important factor in germination and with consistently adequate moisture, would the extra precision still pay for itself? 

These are the main questions to be answered when tackling the decision of a conventional or independent drill for your farm. And, as always, the team at Dutch is always here to help and answer any questions you may have.

 

References:

www.bourgault.com 

MSU, 2020. “Conventional drill versus precision planting in wheat: What Do We Know So Far?”

 

About the Author


Connor Bohachewski
Territory Manager, Northern Saskatchewan & Northern Manitoba

With six years at Dutch Industries, Connor’s experience on his family’s farm in Porcupine Plain, SK and his background in agronomy have come in handy during day-to-day encounters with dealers and producers.