A common view in agriculture these days is that crop yields jumped more in the past 10 years than they did in the previous 30. And it isn’t just yield. There have been similar spurts too in the design of multi-hybrid planters, variable-rate seeding and newer transgenics.
Yet at the same time, a few older concepts are being re-evaluated and reintegrated into management practices on many farms, such as the enormous uptake of cover crops.
Another of the concepts making its way into discussions and onto conference agendas is the Cross Slot drill. The design marries low-disturbance planting with a form of fertilizer banding or knifing closer to the seed at planting.
A generation ago, knifing in fertilizer was considered a risky practice. Placed too close, the fertilizer particle could burn the seed, reducing germination and emergence. But if placed too far away from the seed, there’d be no advantage over surface broadcasting.
Oddly enough, it was roughly 20 years ago that similar technology was touted as something that would “shape agriculture for the next 150 years.” Since then, it’s been researched in various locations by different universities including Kansas State University and the University of Nebraska-Lincoln. A system constructed in New Zealand now seems the preferred design.
The Cross Slot drill has two side blades that run alongside of the coulter, on opposite sides, and lift the soil to create a tab or shelf on either side of the trench. The seed is placed on one shelf and fertilizer on the other. The method of delivery and metering of both products is through simple air-seeder technology with a press wheel firming the soil in place, leaving surface residue intact to protect the seed and conserve soil moisture.
The design works on all grains and oilseeds, including corn and soybeans, as well as cover crops, and can work through heavy residues, even sod. It’s also been used successfully in various settings in the U.S., including the Northwest and Alaska, and in Canada. At the 2017 Innovative Farmers Association of Ontario annual meeting, one grower from the United Kingdom provided his insights on his shallow cultivation system, including the use of a “cross-slot drill” which he built himself.
The company’s literature cites the Cross Slot for providing precise seed placement in a completely undisturbed no-till setting, which it states has been a challenge within no-till management systems for years.
“The lack of tillage has left the one major field operation — seeding and fertilizing — in a whirl of attempts to develop an adequate machine,” says the literature. “The requirements were clear — no soil tillage to maintain seed zone moisture and soil quality; maintain all residues for erosion control and seeding protection; obtain optimum emergence and plant growth for maximum production.”
In terms of the placement of fertilizer near the seed, Ken Ferrie, a consulting agronomist who operates Crop-Tech Consulting in Heyworth, Illinois, found that fertilizer should be no more than two inches from the seed in order to optimize yields. Placing fertilizer farther away from the seed means less of it actually getting to the plant, to the point where if it’s broadcast, only about half actually reaches the plant. The rest can be lost to run-off and to weed competition.
That’s where the Cross Slot system seeks to improve germination and emergence in corn.
“Our research agrees with Ferrie, and the results showed that it didn’t matter whether the fertilizer was above, beside or below the seed, just don’t be more than two inches away,” says Gavin Porter, chief executive officer with Cross Slot North America. “Cross Slot places the fertilizer about an inch to an inch and a quarter from the seed, and this has been successfully trialed up to 500 lbs. per acre without seed burn.”
Porter also says that U.S. growers aren’t gaining in productivity, despite advances in what he calls “companion technologies.” There are improved seed genetics, leading to better hybrids, enhanced soil and microbial testing, better fertilizer and chemical programs and the advent of precision agriculture systems. Top all of those off with better informed and educated farmers.
What’s hampering those advances, however, is the popularity of corn-soy rotations.
“With all of these improvements, why is it that average yields for wheat and corn have remained pretty static?” asks Porter. Average corn yields in the U.S. have effectively stalled at roughly 168 bu./ac. during the four years from 2013 to 2016 (U.S. Department of Agriculture statistics). By comparison, average yields in Ontario were 162.6 bu./ac. during the same period. “The answer is that despite all of these improvements, if you don’t get the seed in the right environment on Day One, then you have already limited your yield potential.”
Added research, different mindset
Aside from seed and fertilizer placement, the one thing the Cross Slot design seeks to maximize is even emergence, thereby improving overall plant stand, plant health and ultimate yield. Porter says this is another area where the Cross Slot drill may help growers.
For years, conventional planting wisdom has placed a higher focus on row spacing, particularly in widths of 30 or 36 inches. Yet Porter contends that research from Kansas State University and University of Nebraska-Lincoln counters that, stating there’s a difference between stand uniformity and emergence. The former has to do with how consistently plants are spaced in the row while the latter has more do to with timing.
“Essentially what these reports are saying is that emergence is more important than spacing,” says Porter. “The horizontal seed placement created by the Cross Slot will give superior germination and emergence. There’s good information relating to the benefits of using narrower row spacing for corn, and since corn is self-pollinating, the closer the plants are the better for pollination, and the better the yield potential.”
The narrower row spacing is something of a return to yesterday, along with the concept of “check-row” planting, where small hills of corn seeds were planted in an equidistant pattern, creating a checkerboard in the field. But it was very time and labour intensive, and was abandoned with the advent of herbicides and more efficient planting systems.
Still, the concept of narrower widths in row spacing is based more on the check-row concept, and it may allow for a drop in plant populations per acre. Research from Dr. Stewart Duncan, agronomist and associate professor with Kansas State University in 2012, addressed the plant populations and stand uniformity issues. His findings showed little yield reduction from non-uniform stands, as long as the final population was within 15 per cent of the target populations.
Research conducted using Cross Slot drills in New Zealand confirmed that with 12-inch row spacing, yields were at least as good as with 30-inch row spacing delivered by singulating planters into tilled soils. The primary difference is that the Cross Slot drill does the job at a much lower price.
“We have a number of successful Cross Slot owners using their existing air drills to successfully seed and harvest corn,” says Porter. “That means farmers don’t have to purchase an additional piece of equipment for their row crops.”
Growers using the system in New Zealand have been planting corn at widths of 30, 24, 18, 12 and six inches. The only difference in the configuration is that as the row widths narrow, the spacing between plants increases (that’s assuming the plant population remains the same). Research indicates that as the distance between seeds increases, the accuracy of the spacing becomes less important. Again, crop yields from random spacing in narrower rows are equivalent to those from conventional 30-inch rows with “perfect” seed spacing in cultivated soils. And sometimes, the yields in narrower rows are higher.
Porter recognizes there are challenges in trying to convert growers on row widths and spacing. At the same time, Cross Slot is completing development of its own row planter with its own dedicated metering system. It was bench tested this past year and will move to the field for trials during the coming growing season.