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Mid-row versus side-band

New research from PAMI finds little difference in agronomic performance.


November 19, 2007
By Bruce Barker

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43bThis was a debate that needed some answers. With the development of mid-row
banding technology, where fertilizer is disc-banded between seedrows, advocates
on either side of the debate have advanced their cases. But a co-operative research
project with the Prairie Agricultural Machinery Institute (PAMI), Agriculture
and Agri-Food Canada, and the University of Saskatchewan's Soil Science Department
found few agronomic differences to choose from between the systems.

"Overall, there were no grain yield differences between the systems 84
percent of the time, and where there were differences, there was almost an even
split between the systems," says Gord Hultgreen with PAMI at Humboldt,
Saskatchewan.

In the PAMI research conducted over three years from 2000 to 2002, and recently
summarized, Hultgreen compared a Bourgault mid-row band to a Flexi-Coil Stealth
side-band system. He seeded wheat, canola and flax at four Saskatchewan sites
including Swift Current, Scott, Indian Head and Star City, which represented
a wide range of climatic conditions and soil types. Anhydrous ammonia and urea
were also compared in the two systems.

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All nitrogen (N) fertilizer was side-banded with the Flexi-Coil Stealth system.
The Stealth system uses a side-band knife on 10 inch row spacing to place the
seed one inch above and one inch to the side of the N fertilizer. Phosphate
(P) fertilizer was side-banded when using urea and seed-placed when ammonia
was used.

In the Bourgault system, seed was placed through Bourgault knives on 10 inch
centres. Running mid-way between the knife openers, the Bourgault mid-row coulter
placed N fertilizer in bands between every second set of seedrow knives. As
a result, the urea or ammonia was placed in a mid-row band five inches to the
side of the seed. Phosphate was always seed-placed in the mid-row band system.

Nitrogen rates ranged from zero to 107 pounds per acre at Star City and Indian
Head, and zero to 80 pounds at Scott and Swift Current.

Few differences to choose from
Overall, there was a wide range of climatic conditions at the four locations
over the three years, varying from severe drought in 2002 to above normal precipitation
at some locations in 2000. The entire trial at Scott and the wheat crop at Star
City were lost in 2002 due to drought, and those results were not included in
the analysis.

Looking at nitrogen source, urea and ammonia provided similar yield results
with the mid-row and side-band systems. Hultgreen says this research falls in
line with others that show both urea and anhydrous ammonia can be safely side-banded
without crop damage, although he notes that under some conditions, there could
be a small risk of seedling damage with side-banded ammonia.

"Concern has been expressed in the past that you couldn't use ammonia
in the drier Brown soils, and that you might have ammonia losses. We didn't
see that, and although we didn't measure ammonia losses, the yield results would
indicate that there wasn't any difference in performance," explains Hultgreen.
"The caveat, though, is that under very dry conditions with side-band openers,
there is a potential risk that the ammonia could get into the seedrow. We didn't
see it, and I'm not knocking ammonia, but there is a higher risk with ammonia
than urea in those circumstances."

Looking at grain protein, placement of N in a side-band or mid-row band had
little effect on wheat protein. There was a trend for lower protein on anhydrous
ammonia treatments, although the differences were not great.

Where there were significant yield differences, the mid-row band system had
higher grain yields six percent of the time, and the side-band system had higher
grain yields nine percent of the time.

Hultgreen says the situations where mid-row banding produced lower yield results
were caused by N stranding in the extra dry conditions of 2002. "Under
dry soil conditions during the first few weeks after seeding, access to nitrogen
from the mid-row band is limited due to the distance between the seedrow and
the nitrogen band."

In cases where the side-band system had lower yields, Hultgreen suspects it
may have been due to poor seed to fertilizer separation. "There really
was little to choose between the systems. I would be comfortable recommending
either one."

Each system has its merits
Blair McClinton, Saskatchewan Soil Conservation Association's executive director,
says that choosing between the systems often comes down to personal preference,
especially considering there are few yield differences. "There are pros
and cons to each system, and the PAMI results show that if the fertilizer is
placed in the ground in the correct place, you won't see much of a difference.
We kind of expected that."

With the mid-row band system, both McClinton and Hultgreen say the seedbed
is left with a smoother finish and that it is a more foolproof system. With
the N fertilizer placed in the mid-row band, there is zero risk of seedling
damage from either urea or ammonia fertilizer. Since seed placement is independent
of fertilizer placement, a case can be made that seed depth can be more accurately
set, as well.

When using side-band systems, the seeding operator has to be more attentive
to seed placement and seed-fertilizer separation. "We knew from previous
research that side-band openers work with anhydrous ammonia. But you have to
be careful when the opener starts to wear. It wears from the bottom up, so you
start to lose the vertical separation, which increases the risk of seedling
damage, especially with anhydrous ammonia," explains McClinton.

Hultgreen also says that with side-band openers, more attention must be given
to adjustments such as fan speed and ground speed. If fan speed is too high,
small seeds like canola can be blown into the fertilizer row. Likewise, if ground
speed is too high, seed-fertilizer separation can suffer. Side-band openers
typically leave the ground slightly rougher after seeding, as well.

"On the flip side, the fertilizer won't be stranded with side-band openers.
You know the plants will be able to access the fertilizer, so it is really a
matter of weighing the pros and cons," says Hultgreen.

On the financial side of the debate, there are likely no clear-cut winners.
The seed knives on a mid-row band system are much cheaper to replace than side-band
or paired-row openers. However, that may be overridden by the additional cost
for mid-row band coulters. The coulter system may also have higher maintenance
costs due to the additional bearings, which are not present in side-band systems.
Hultgreen says that side-band openers may also have a higher draft requirement,
which would increase operating costs.

Hultgreen's research does not show a clear-cut winner because both systems
can work, however, the research is reassuring. "If a farmer asks me which
system is better, I can't answer that question because both can provide excellent
yield results. But if he says he likes one system better and asks if there any
problems with the system, I'm not afraid to tell him the advantages and disadvantages
of the system." -30-