When it comes to achieving higher yields, no-tillers have three major issues to tackle: cold and wet spring soils; high density in the lower portion of the topsoil; and large amounts of residual fertility locked in the no-till stover.

Cold wet soil slows machinery carrying capability, seeding emergence and vigour. higher density on the bottom part of the topsoil layer causes reduced nutrient uptake, reduced moisture carrying capacity and eventually reduced root growth and yield. Yields can be enhanced by releasing the fertility in the previous crop’s residue for the growing crop.

All of these limitations can be alleviated with the proper use of true vertical tillage tools.

Let’s use the following analogy: topsoil is similar to a lake or body of water. Different creatures have different preferences as to where they live in the water column. For example, algae live near the surface where they feed on higher-level nutrients and sunshine. Bigger fish prefer to live lower in the lower water column, and bottom feeders obviously live on the bottom. Some creatures move up and down through the water column as they feed. Soil is similar. Certain microbes and bacteria live in the upper portions of the topsoil, certain fungi prefer the middle of the soil profile and others, the bottom.

Move soil vertically

If you disturb the soil by totally inverting it, all of the creatures in the soil have to build and find new homes. It takes a while for their populations to recover. The beauty of vertical tillage is that because all the movement is vertical, the existing populations of creatures in the topsoil are not displaced or destroyed.

Large amounts of residue on the soil surface act like an insulating blanket keeping the topsoil cold. Reducing residue volume by processing with a vertical tillage machine accomplishes a number of things. It allows more sun and air into the upper portion of the soil surface for warming and reduces or pre-processes the amount of residue that the seeding equipment needs to deal with. Vertical tillage residue processing also begins the nutrient release process from the stover. Opening the very top of the soil adds air that warms the seedbed. You are not inverting or stirring the seedbed, just adding air.

A second analogy is that true vertical tillage is much like a wood stove. When you add air to a wood stove, you increase the amount of heat and combustion. When you add air to the seedbed portion of topsoil, the soil warms and the warmth increases soil life activity. You get a soil creature population “boom” or “bloom.”

There are many benefits to warming the top one and three-quarters to two inches of topsoil:

• Seeding can occur many days earlier because the soil can carry the planting equipment.
• Seeds are placed in an ideal warm environment with neither excessive or a depleted soil moisture.
• Seed germination, vigour and speed of emergence are improved.
• Populations of existing flora and fauna bloom to help in the nutrient uptake process.

Manage crop residue

Crop residue, especially corn, contains a large amount of nutrients. In a standard no-till system these nutrients are usually released late in the growing season, once higher temperature and rainfall cause decomposition. This usually happens too late to be used by the growing crop. If these nutrients are recycled more quickly using a vertical tillage tool pass, they will be available for the growing crop, giving the crop a boost, and potential yield gain.

Over time nearly all no-till soils stratify. The top two inches of topsoil — the layer that received direct fertilizer application and mechanical tillage soil movement — tends to become open and loose, and very high in nutrients.

The soil from two inches down to six or eight inches tends to get quite dense from lack of mechanical tillage, lack of direct fertilizer application and wheel traffic. This increased density reduces the soil’s ability to store water and exchange nutrients. Some no-till soils can become so dense that moisture and nutrient exchange can stall. A tell tale sign that this has occurred is two to three years of undigested residue visible on the soil surface.

Reduce soil density

There are a number of ways of helping alleviate this lower topsoil density issue. One is to pull a vertical shank that lifts the soil profile and shatters it without stirring it. In-line rippers are an example of this. Some vertical tillage systems offer the option of putting shanks into their framework to offer upper topsoil warming and lower topsoil fracturing. Just make sure that the shank is only moving soil vertically if you wish to keep the vertical tillage advantage.

Another option is to use vertical tillage tools that offer a jack hammer effect. Certain machines have rolling coulters that vibrate and shatter the lower topsoil density. Reducing density levels of the lower topsoil increases root growth and plant, water and nutrient uptake. It also increases the water holding capacity of topsoil, which can add to drought tolerance in certain years.

Adding all the positives of vertical tillage into a no-till system without displacing the gains that have been accomplished creates a synergy. Combining the benefits of vertical tillage — increased soil warming, increased residue breakdown and lower soil density —with the benefits of no-till’s improved soil structure, decreased soil erosion and soil conservation can lead to further yield increases.

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Other steps to successful canola seeding are:

• Targeting final plant stands according to seed size.
• Handling the canola in the most efficient and gentle manner possible.
• Placing the seed in exactly the correct spot in the seedbed.

Some canola growers are starting to contemplate optimum seeding rates in terms of final plants per acre (PPA), rather than pounds of seed per acre.

Farmers working on lowering seeding rates tend to aim for between 250,000 and 300,000 PPA with some trial work at the 200,000 PPA level to check where the consistent bottom end is. Right now there isn’t enough evidence to verify that rates as low as 200,000 PPA can be successful in all soil and climate conditions and with differing genetics.

The Canola Council of Canada recommends seven canola plants per square foot — 304,920 PPA.

Focus on number of viable plants

Seed planted don’t equal viable plants per acre. Some current seeding methods have seed mortality rates as high as 50 per cent. With high vigour seed, gentle handling, precision seed placement, and good seedbed conditions, seedling mortality rates of 10 per cent can be achieved.

The size of canola seed greatly effects how the seed will be metered. Treated canola seed size can vary from 6.0 grams/1,000 seeds (75,000 seeds/lb.) to 3.8 grams/1,000 seeds (112,500 seeds/lb.).

If a 90 per cent survival rate can be achieved this would translate to seeding 3.7 lb./acre (with seed at 75,000 seeds/lb) to 2.47 lb./acre (with seed at 112,500 seeds/lb.) to achieve a 250,000 final plant stand.

This is a significant difference in seeding rates. If a large seed size of 75,000 seeds per pound were planted at 2.47 lb./acre, final stand would only be 166,725 PPA, assuming 90 per cent survival.

Especially at low seeding rates it’s important that meters can deliver precisely the number of seeds per acre, and distribute them evenly across the field. Uneven metering that distributes bunches of seed or leaves unseeded patches will lead to reduced yield.

Ensure undamaged seed

In the air distribution system too much air volume or too much air velocity can damage seed and reduce your final number of plants per acre.

One simple method to check if there is enough air volume is to remove a hose from an opener and point the hose straight up. Then hand crank some seed into the air stream to see how high the seed goes over the top of the hose. If the air carries the seed six to eight inches up over the edge of the hose, there is enough air. If the seed is propelled two to three feet up past the end of the hose, the air volume needs to be reduced. If a single fan feeds the seed air stream, this is as simple as dialling the fan back. If the fan services both the seed and fertilizer air streams, baffles will need to be adjusted to concentrate most of the air to the fertilizer stream.

Rough edges and contact points inside the air delivery system need to be reduced or eliminated. Tower lids need to be cushioned or spiralled to give the seed gentle turns at the top of the towers. On very wide drills that require large air volumes to get to the outside edges of the wings, seed brakes might be contemplated to eliminate the possibility of seed bounce at the bottom of the trench.

Knowing your seedbed helps manage mortality

One of the biggest challenges to reducing seed mortality is the exact placement of seed in a warm, moist seedbed. If your seedbed is freezing cold, saturated, covered with a two-inch crust, or hard as a rock do not attempt to seed at low rates. You will be flirting with disaster.

Low rate canola seeding machines must have parallel linkages on each row for precise depth control. Without individual row depth control, seed depth cannot be controlled accurately enough to give consistent results. Consistent seed placement at one-quarter to one half an inch into firm, moist, warm soil has shown to give the best results. Accurate seeding depth is best achieved (in order of accuracy) by double disc, single disc and knife style opener systems that are individually depth controlled.

Watch your openers

Opener closing systems are also extremely important. Gentle packing without excessive pressure assures the seed a good home to germinate from.

Opener performance in heavy residue can be an obstacle to maintaining proper seed depth. Conditioning and evenly distributing residue will improve seeding accuracy. Opener depth adjustments are required to compensate for a half-inch layer of chopped cereal straw.

Double disc and single disc precision drills are required for zero tilling canola into heavy residues such as corn, sunflower or stripper header combined cereals and flax. These heavy residues require the additional clearance of disc drills to maintain seeding accuracy without plugging.

With careful attention to detail, precision air seeding systems can give uniform high yielding stands. †

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