Features Agronomy Corn
No-till disc openers work well: Part I

When direct seeding systems were first being developed within western Canada,
shank-based hoe or shovel openers were by far the most popular types of no-till
seeding tools used by prairie farmers. During the early stages of no-till farming,
the disc-type seed openers were unpopular due to poor penetration and their
tendency to hair-pin, especially in the presence of unanchored crop residues
present on the soil surface.

Modifications increase functionality of hoe openers
Over the past decade or so, hoe-type openers have been refined and improved,
such as providing the ability to side-band fertilizer beside the seedrow, to
meet the demands of no-till farmers. As a result of these modifications, the
hoe/knife openers have managed to maintain their dominance with prairie no-till
farmers. In the interest of achieving seeding with minimal soil disturbance,
some of the openers gradually took on a knife-like appearance. However, disc-type
openers have also continued to evolve and have begun to make inroads, especially
in the drier regions.

South Dakota visit causes re-examination of practices
Following a visit to a South Dakota no-till research farm, several growers located
in southern Alberta began to re-examine the potential role of disc openers as
part of a systems approach to no-till cropping. Benefits such as less soil disturbance
had to be balanced against the risks of too much residue build-up and cooler
soil conditions.

Practical benefits of using stripper headers
Two key requirements were to diversify crop rotation and to do a better job
with residue management, such as the addition of a stripper header attachment
to the combine. Stripper headers excel in cereal crops, leaving the majority
of the straw standing and anchored in the soil: a big advantage when using disc
openers.

Additional seedbed moisture important practical benefit
On farms located within southern Alberta, more often than not, seedbed moisture
is less than ideal at the time of seeding. The additional surface moisture provided
by the extra snow trapped by the taller stubble can be a real positive benefit.
In addition, as a result of the taller stubble, a significant change is created
in the microclimate present at the soil surface. This makes it possible to retain
more of the precious seedbed moisture, as a result of less evaporative soil
moisture losses that are associated with the strong spring winds.

Disc openers create a wider window for seeding
Rod Lanier made the switch from using a narrow knife opener, to the John Deere
disc opener two years ago. He says his single-shoot disc openers allow him to
effectively seed over a wider range of soil moisture conditions than was possible
with his knife-equipped air-seeder. "The greatest disadvantage of the knife
opener was that it was not effective in wet soils."

Wet soils are a challenge for knife openers
Lanier claims that in wet seedbeds, "The knife opener would result in smearing
of the seedbed and the creation of lumps of the soil over the seedrow."
He also points out that "This resulted in uneven crop emergence, which
created serious timing and risk problems for his post-seeding, pre-emergence
weed control applications." Lanier operates Neveridle Farms, which is located
near Lethbridge. This farm has a 20 year history of working with the development
of no-till farming systems.

Faster seeding and a more uniform crop
There were several other key advantages resulting from the use of a disc seed
opener on his farm that were cited by Lanier. "Using a disc opener allows
me to seed faster and to achieve the more uniform crop emergence that is essential
for effective weed control. Also, if I need to seed deeper to place my seed
into moist soil, a disc opener allows me to achieve a more uniform crop emergence
and better plant stand than I was ever able to accomplish using a knife opener.
In addition, my power requirements for seeding have been reduced."

Earlier seeding critical
Lanier believes that early seeding is essential to the success of his farming
operation. He uses April 10 as a general target for the date to get started
with seeding. However, he feels that attaining soil temperatures of five degrees
C is also critical for deciding when he should start seeding. He does not feel
that colder soils are necessarily an issue associated with the taller stubble.
Don Wentz, a reduced tillage agronomist located at Lethbridge, suggests, "Producers
have to weigh the potential rewards of seeding early over the risk of getting
some frost damage, since soils covered with residue warm slower."

Knife versus disc debate
Rob Dunn, a conservation cropping specialist with AAFRD, points out the debate
over knife or disc openers has been going on for some time and is likely to
continue for some time. He notes that "Improved disc designs, better straw
management and diverse crop rotations have helped to accelerate the trend toward
disc systems in the drier soil zones. Using a disc drill when first getting
into direct seeding may not have been a great idea, but if you farm in a drier
region, it is worth considering for your next purchase."

The next issue of Top Crop Manager will have more grower comments on
the benefits of combining stripper headers and disc openers in a no-till system.

John Harapiak has approximately 40 years of western Canadian based
fertilizer related experience. He will continue to contribute stories to
Top Crop Manager. He can be contacted by e-mail at: jharapiak@shaw.ca.