| | The development of conservation tillage (CT) technology has largely been a case of"the cart leading the horse,"says AgTech engineer Lawrence Papworth. In other words, one technology drives the need for complementary technology. As one technology makes seeding faster, for example, something else must come in to make fertilizer application similarly efficient.
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"Double-shooting fertilizer, the re-emergence of disc openers, the new developments in residue managers and soil levelling devices are all trends in conservation tillage that are connected to the same theme: making CT practices more efficient and more economical,"says Papworth.
Double-shooting fertilizer makes gains
There's no need to look further than changing trends in fertilizer placement to find an example of how new farm technology drives further innovations."A general movement away from air seeders and towards air drills necessitated the development of new ways to apply fertilizer," says Papworth."With air seeders, seed could be planted and a high level of nitrogen could be applied at the same time because of the wide seed spread of the openers.
"However, because air drills are so much more precise, some nitrogen can be applied along with the seed but usually not as much as the crop requires. The solution, then, has been to place fertilizer in a separate band from the seed. Double-shoot openers have enabled this."
Double-shoot openers place a band of fertilizer two to three inches below and to the side of the seed in a single pass. The advantage of this side banding method, says Papworth, is that high rates of fertilizer can be applied while minimizing damage to seedlings.
Low draft double-shoot openers are the latest wave of double-shoot openers, says Papworth."They place the seed and fertilizer at the same depth. This results in less power required to pull the air drill."
A number of manufacturers make low draft double-shoot openers. The AgTech Centre recently tested many of the low draft openers on the market."Performance of the openers was very good, although mixing of seed and fertilizer occurred with some of the openers tested,"says Papworth."Small amounts of seed and fertilizer mixing at the same depth were not a concern."
Mid-row banding is another method that places fertilizer to the side of the seed. The difference between mid-row banding and double-shooting is that fertilizer is placed between every second seed row using a separate knife, disc or coulter.
"The major advantage of mid-row banding is that it works well in all types of soil,"says Papworth."However, both methods work on the same basic principle: maximize nitrogen, minimize seedling damage."
Disc openers back in style
Disc openers are an example of an older technology that has been refined to the point where it is considered by many to be a newly viable — and with some crops even superior - tool for conservation tillage, says Papworth.
"Disc openers are definitely coming back,"he says."Many years ago a lot of the zero-till drills had disc openers, but there were a lot of problems with durability. Today, most manufacturers have addressed that problem, and durability is not the issue it was 10 to 15 years ago."
These old-school openers are particularly appropriate for small seeds, such as canola and mustard, that require planting at a shallow and accurate depth."Disc openers are definitely the easiest openers to use if you are planting smaller seeds and want to minimize disturbance,"says Papworth."And, when combined with narrow row spacing, they can be a major factor in higher-than-average yields."(See Sidebar,"Narrow row spacing gets results under direct seeding.")
What tends to turn producers off of disc openers is the high cost, says Papworth. They have more metal and bearings that naturally increase the price tag. And because of the weight required to hold the discs in the ground, they also have a tendency to use a lot of power at deeper seeding depths. But this is generally not a problem if people are seeding shallow into soil with high moisture content.
Residue managers get question marks
Residue management is a crucial component of any conservation tillage program as plant residues serve to enrich the soil, conserve moisture and minimize weed germination. It's a practice traditionally done at harvest time with chaff spreaders and straw choppers. If the residue is still not spread widely enough, producers often make one pass with a heavy harrow — a practice that tends to disturb the soil.
The new residue management tools are used prior to or at the time of the seeding operation, says Papworth. They represent a more conservation-friendly option than tillage to accomplish this, but the question is just how much efficiency these residue managers offer over more traditional methods.
"From what we've observed in our research, it seems that residue managers only offer an advantage where there are exceptionally high yields and exceptionally high amounts of chaff, such as on some irrigation farms,"says Papworth."At this point, between the yield and cost factors, I can't see the purchase of residue managers being very widespread."
That doesn't mean there may not be a place for them on the farm in the future."Like most technology, residue management technology is ever-evolving,"says Papworth."There's a prototype model for hoe openers, for example, that shows some potential.
"It basically consists of a wheel that runs to the side of the opener. The wheel pins the residue beside the opener rather than pushing it up the shank and plugging up the opener,"he says."We used it with a Flexi-Coil shank in our test and it worked well. I think it'll catch on when it's made commercially available."
Soil levelling devices rethought
Soil levellers — often referred to as"furrow closers"— are another example of CT technology that has enjoyed newfound popularity. This is again due in part to technological fine-tuning, says Papworth.
"The earliest soil levellers involved a set of rotary or tine harrows that, while workable, tended to get plugged up easily,"says Papworth."Today, the most common soil levellers forego harrows with a set of discs attached to the shank. These discs throw the soil back on the furrow or deflect soil to the furrow."
The primary benefit of this is that it allows the drill to operate at high speeds with a wider opener, creating a significant time advantage."Some producers also like wider openers because of the increased seedbed utilization and the minimization of seed damage from nitrogen,"he says.
A variation of the basic soil levelling concept involves a single fluted disc that attaches to the shank and runs behind the opener."We found that the one model we tested — one manufactured by K-Hart — did a good job of covering the seed for wide openers."
Another variation is the mid-row leveller available from Haukaas."These are basically an additional set of packers which fit ahead of and between the packers,"says Papworth."Unfortunately, AgTech has not yet had the opportunity to test these levellers."
The future of CT
So what does the future of conservation tillage technology hold? Papworth believes the process of refinement and response will continue to drive the practice forward and make it more attractive to producers.
Variable speed transmission - "Conservation tillage technology is constantly being fine-tuned to make it even more efficient,"he says."A good example of this is tractors with variable speed transmission (VST). Tractors with VST perform at optimum engine performance — and as a result optimum fuel efficiency — regardless of seed depth or soil conditions. They're ideal for farm operations with a variety of conditions, power requirements and seeding depths."
Like most CT technology, the major drawback of VST is cost."However, with the price of fuel rising like it is, it's becoming easier to justify the cost of such a purchase,"says Papworth.
Cross Slot openers - Another technology worth keeping an eye on is Cross Slot openers. These low-disturbance single-disc openers place seed and fertilizer in horizontally separated bands or "slots."
"Cross Slot openers replace residue over the slot and trap moisture in the slot. This helps assist germination even in very dry soils,"says Papworth.
Cross Slot openers have actually been around for a number of years, says Papworth, but are poised to make a comeback as producers realize their positive effects on soil viability."The problem is that they're hard to find in Canada,"he says."However, it's a technology to stay aware of as it becomes more available here."
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