By Geoff Geddes
Depending on who you talk to, tillage can be good, bad, ugly, or all of the above. Like any tool, how and why you use it will determine whether tillage is an asset or liability for your business.
Conventional and conservation tillage are the primary types and are simply measured by the amount of crop residue or vegetative material left on the ground post-harvest.
Knowing the ins and outs of tillage and the different options is important, but only if you can answer a burning question: “what’s in it for me?”
“Tillage loosens and aerates the soil, which allows for the deeper penetration of roots,” says David Lobb, professor in the Department of Soil Science, Faculty of Agricultural and Food Sciences at the University of Manitoba. “It controls weeds and mixes organic matter, fertilizer, and manure with the soil. Other benefits include seedbed preparation, seed placement, soil-seed contact, incorporation of nutrients and crop management (hilling and harvesting). Additionally, tillage can accelerate both the breakdown of excessive crop residue and the warming and drying of the soil.”
Yet as everyone knows, there are two certainties in life: you can’t control the weather, and for every upside there’s a downside. Tillage may lead to the loss of soil moisture, increased wind and water erosion, and consume significant amounts of fuel. Of these, soil erosion may be the biggest concern.
Save our soil
“If farmers adopt conservation tillage, the health of the soil might not be protected,” says Lobb. “Conservation tillage, by reducing soil disturbance and increasing crop residue cover on the soil surface, can effectively control soil degradation by wind and water erosion. That said, there is another erosion process, called ‘tillage erosion,” which complicates the conventional understanding of how to conserve soil through tillage practices.”
As Lobb explains, tillage erosion is the net loss and accumulation of soil that occurs within a field due to variability in soil movement during tillage. Soil movement and its variability are affected by several factors: type of tillage tool, speed and depth of tillage, operator’s manipulation of speed and depth during tillage, and soil conditions, including the amount of plant residues. Over time, tillage progressively moves soil from upper slope to lower slope landscape positions within a field. Tillage erosion is often found to be the major cause of soil loss where cultivated soils are most severely degraded by soil erosion.
“One commonly used practice in conservation tillage is the employing of a chisel plow for primary rather than a moldboard plow,” says Lobb. “Although the chisel plow reduces the risk of wind and water erosion, it can result in greater tillage erosion. Another commonly used conservation tillage practice is the reduction in number of passes of discs and field cultivators used in secondary tillage operations. This can be an effective means of reducing soil erosion by wind, water and tillage. However, some forms of crop production, such as potato production, or tertiary tillage operations such as seeding, hilling, and harvesting, may result in more tillage erosion than primary and secondary tillage operations combined. Consequently, some crop production systems would need to go well beyond conventional conservation tillage to maintain or restore a healthy soil.”
To avoid erosion problems, many farmers just opt for no-till seeding. The no-till approach avoids any mechanical tillage of the soil and pushes for zero soil disturbance. In contrast to the multiple passes of equipment in the conventional approach, no-till can involve just one pass through the fields for planting.
Pick your spots
Still, there is a role for tillage to play if used in moderation.
“At one time, tillage was a standard practice on the Prairies and elsewhere for growing crops,” says Jim Halford, professional agrologist and farmer in Indian Head, Saskatchewan. Halford invented the Conserva PakTM, a patented zero till seed opener.
“I advise today’s farmer to use tillage very selectively,” says Halford. “For example, if you have areas of your field with very heavy residue or that need smoothing out, you might do some harrowing to address that. Also, with the wet years we had recently in Saskatchewan and Alberta, some parts of your field could have been flooded and started to grow grass, bullrushes and cattails. Then the water finally disappears, and you want to get that land back to farming. If you just have limited residue out there like short grasses, you can mow it and seed directly, but if you have 4-5 feet of high residue, just mowing it and trying to seed through it won’t work. In that situation, people have used tillage quite effectively.”
The key, notes Halford, is to only do those areas that were affected. Otherwise, you risk downgrading the structure of the soil and residue in the rest of the field, thus risking loss of moisture and organic matter and reduction in the ability of the soil to provide nutrients to future crops.
The situational use of tillage works well for Adam Gurr, a grain farmer near Brandon, Man.
“We practice controlled traffic farming (CTF), a system built on permanent wheel tracks where the crop zone and traffic lanes are permanently separated. When we have wet seasons in this area, the sprayer might make three to four passes in the same spot and eventually create ruts.”
Tillage has proven an effective tool for leveling off those ruts, and the CTF system really lends itself to the selective approach.
“The benefit of CTF is that when ruts do form, we know exactly where they are, so we don’t have to resort to full field tillage to renovate them.”
A demanding industry
Though tillage may be used less frequently today, at least one equipment dealer is still seeing great demand for it.
“We see that farmers are using our machines in Western Canada because higher yielding crops have more biomass,” says Anson Boak with Salford Group in Manitoba. “The stalks, stems, leaves, and parts of the plant that aren’t harvested are left in the field to decompose, and that decomposition isn’t happening fast enough from season to season. After a few years of accumulation, seeding equipment becomes challenged by the buildup of residue, machines start to plug up, and seed placement is affected. Also, matted residue keeps the ground cool and wet, which challenges seeding equipment, and has a major impact on crop germination.”
As farmers seek more effective mechanical means to accelerate residue composition, they help drive strong sales of Salford’s tillage equipment in Western Canada.
“Producers find their seeding equipment performs better when there is less residue to contend with and that residue has been chopped into smaller pieces, which flow better through the ranks of air drills.”
As well, Boak is finding that aggressive tillage models like Salford’s 5200 Enforcer, a disc-based primary tillage machine, are being used in Western Canada for specific purposes.
“The most common call we’re seeing for more aggressive tillage units is organic farming where producers cannot use chemical means for weed and pest control,” says Boak. “These units help to control yield-limiting factors like weeds and pests without the use of chemicals. We’re also seeing them used for long-term pasture rotations. After long periods of use, grazing pasture land becomes compacted and heavy tillage is needed to convert that land back into crop production.”
Given the varying viewpoints, the issue of “to till or not till” may come down to when, why, where and how tillage is applied. As for whether it’s good, bad or ugly, that’s a lot like the weather outlook: it depends on who you ask.