Along with timely planting dates each spring, other decisions need to be made in primary tillage and planting operations. For farmers using no-till and reduced-tillage conservation practices, special care needs to be taken regarding planter settings and soil moisture conditions.
On March 11, Ryan Bergman, program coordinator with Ag and Biosystems Engineering at Iowa State University, spoke at the Northeast Iowa Research and Demonstration Farm near Nashua. It was our research farm association’s annual meeting on “Tillage and Planting Tips for a Successful Spring.”
Ryan pointed out that it’s good to remember that once the bag of seed is opened, “everything we’re doing revolves around protecting the potential of the seed and making sure we get maximum yield of that seed as we go all the way through harvest.”
Each growing season brings yield limiters that we have a varied level of control over. As far as soil, climate and environment, those are primarily out of our control. There’s not much we can do about it except adapt as best we can. We can, however, have control of crop input decisions like seed selection, how much fertilizer to apply, sidedress applications, determining if a fungicide application is warranted, etc.
Adjusting to soil conditions
Another limitation is measured by a newer relative terminology used in the equipment industry called “production system job quality.”
Ryan explained this as making sure we execute every pass across the field to the highest degree of quality possible. For example, every time we drive a piece of equipment across the field, are the conditions right to be there that day? Is the equipment properly set up? Are soil conditions right to support the equipment? Although we have control over the equipment aspects, we don’t have control over soil conditions, as they are what they are at a given time.
There are many reasons why tillage is used. The most common include creating a uniform seedbed that supports excellent seed-to-soil contact, leveling the field after fall tillage, warming up the soil before planting, incorporating herbicide or fertilizer into the soil, and sizing and incorporating crop residue prior to planting.
It’s important to think about what the goal is for the tillage operation and evaluate the quality of the job being done. A big factor in this is soil moisture, as it is a major driver to the success or failure of a spring tillage system.
Breaking up soil compaction
One way to evaluate a tillage operation is to stop the tractor, get out, walk behind the tillage tool, get on your knees and pull away the loose soil with your hands. (Don’t use a shovel as it can compromise the area of interest.) A good leaf blower could also be used to blow the loose soil away.
Start at an area where there’s not a lot of wheel traffic (center of the tillage tool or out by the wings) and compare it to an area behind a set of tractor tires, or combination of tractor tires and tillage tires. Using a visual assessment like this helps us understand the differences between the two areas and how compaction is set up in the field in conjunction with how the tillage tool is interacting with it.
When looking at the area behind the wheels, we can sometimes see imprints of tire or tractor lugs. Depending on soil conditions, we may be able to set our tillage depth deep enough to take out the compaction zone without compromising an optimum seedbed. However, if the tillage depth needed to remove the compaction is too deep, where there’s too much soil moisture, we risk the chance of having a cloddy seedbed.
This tillage evaluation method is a good option to consider if you’re trying out a new tillage tool or assessing whether you need to replace your shovels.
Assessing ‘ride quality’
Over the last couple of years, ISU ag engineers, including Matt Darr and Ryan Bergman, have been researching the “ride quality” of planters in relation to the quality of tillage and seedbed conditions. Ride quality measures the dynamic “bounce” of the planter (vertical movement of the row unit) and is an indicator of smooth planting conditions.
Ride quality ranges from zero to 100, and typically for most planting conditions, ride quality remains in the 90s, with poor ride quality defined as less than 94%. Conditions that can increase ride quality problems include high-speed planting in marginal soil conditions, or planting into cloddy or high residue conditions.
ISU research shows as ride quality decreases (lower than 94%), planting depth and seed-to-soil contact is reduced. Corn vigor is also reduced. In a recent study, 16% of a field was affected by poor ride quality due to variability in field smoothness, which equated to an 18% yield reduction. In another study, three different tillage depths (1.7 inch shallow, 2.3 inch optimal and 4 inch deep) were compared to ride quality and seeding depth. It was found that a 0.5-inch difference in tillage depth pushed the planter from acceptable to non-acceptable ride quality, and ultimately seeding depth consistency.
Spring planting season is a busy time with many decisions needing to be made to ensure maximum yield potential. Besides seed selection, fertility, herbicide and other agronomic considerations, tillage and planter operations need to be thought out. The quality in which tillage is conducted has shown to be a limitation to yield potential. Careful assessment ensures optimum seedbed conditions are met to allow the best ride quality of every row unit on the planter.
One of the primary factors for this is soil moisture and timing of the tillage operation. Research shows that ride quality will be diminished as cloddy soil conditions increase at planting. Keep in mind, if ride quality decreases, slow down the planter or adjust downforce settings to compensate for the poorer soil. Also, especially in no-till and reduced-tillage systems, greater emphasis must be placed on the soil-engaging components of the planter since the planter replaces tillage equipment operations used in the past.
Basol is an ISU Extension field agronomist at Nashua in northeast Iowa. Contact him at firstname.lastname@example.org.