Welcome back to our 2021 Seed to Grain Series, powered by Solutions 360! Our team wanted an in-depth look at the factors that can affect your yield at the time of planting. In Part 2, we’ll focus on the top 4 factors that impact your stand, and how to best measure them in the field.
While real-time planter performance data isn’t new, how do we know what numbers to really watch? We’ve got all sorts of readings to choose from – singulation, CoV, ride quality, average population, depth, just to name a few. It can be confusing to figure out which numbers have the most impact. The easiest way to break down these measurements is to ask yourself which of the 4 key factors they fit into. Our staff agronomist, Todd Farver, gives you an in-field explanation in his latest video!
The single largest factor that affects your corn yield? Uniform emergence. On average over multiple studies, it’s been shown that this factor can have a 5-9% impact on your total yield. So, if you average around 200 bushels/acre, that’s a 10-18 bushel/acre bump that you could be missing out on! There are many reasons why uniform emergence has such a huge impact on your corn stand.
Let’s start with seed depth. While soil type, hybrid variety, and planting conditions can all help dictate what your depth should be, it’s a good rule of thumb to stick in the range of 1.5 to 2.5 inches. For our test plot, we used a depth of 2″. Depth is an important factor because it dictates two major emergence players: moisture distribution & seed-to-soil contact. In very dry soil conditions, you may be encouraged to ‘plant to moisture’ – in essence, dig until you find a depth where moisture is consistent throughout the trench, and aim for that as your target (within reason). Regardless of whether you’re planting to moisture or have a target number in mind, having even & consistent moisture distribution across the seed bed is key to good emergence. If you have one seed with enough water to germinate and emerge properly, and another without, the second plant is going to emerge slower than the first. Because the first plant is already above ground, it may treat the second plant as a weed and water, sunlight, and nutrients won’t be distributed equally.
Seed-to-soil contact sets the tone. Seeds & root systems absorb water and nutrients from the soil around them. So, if a seed is not adequately covered with soil, how can we expect it to thrive? Not only can poor seed-to-soil contact lead to slower and more uneven emergence, it can also affect nodal root system development. The nodal (or top) roots need to develop correctly for your corn to have a strong structure, and for good water/nutrient uptake as the growing season progresses. Make sure the entry & exit portions of your row units are a match for your soil type & field conditions. For disk openers, check them before every season to make sure they aren’t overly worn and give you a nice trench formation. Closing wheels can have a huge impact on not only seed-to-soil contact, but also the condition of the trench overall. If your closing system is too aggressive, you could be packing the seed down too far and risk emergence issues. On the flip side, if your closing wheels aren’t properly covering the seed, the crop won’t receive nutrients to jumpstart germination. John Deere offers options to fit every cropping system, so be sure to chat with your Van Wall Sales or Parts Professional if you feel your closing system needs an upgrade.
It’s also important to check your downforce impact. Too little downforce results in row unit bounce, meaning your seed depth will be inconsistent. Too much downforce can lead to sidewall compaction and unfavorable root growth. While there isn’t one silver bullet number to shoot for, you need to evaluate each field’s conditions before (and during) planting to properly set your downforce. While planting, dig a section of your furrow to check for smeared, shiny walls and an unbroken ‘V’ shaped trench. If you notice that your seed trench is holding a firm shape in the walls & bottom that will likely harden, lessen your downforce. Not only can these hard conditions cause poor seed-to-soil contact, they can also cause roots to grow laterally instead of vertically. On the same note, if you dig in the trench and notice that your depth is varied widely between seeds, add a little more downforce until the depth evens out. John Deere’s Individual Row Hydraulic Downforce helps significantly reduce the variability you see in the field, as it monitors and automatically adjusts the downforce for each row independently.
- For corn, aim to stick with a depth between 1.5 and 2.5″. This number will vary based on soil type and conditions.
- If you’re experiencing very dry soil conditions and an uncertain weather outlook, consider planting to moisture.
- Dig in the seed trench while planting to check for sidewall smearing, unbroken ‘V’ shaped trenches, good seed-to-soil contact, and to measure the actual depth.
The next biggest player in setting your field up for success is planting within the optimum window. Did you know this can have a yield impact of 2-5%? Corn that is planted later has less chance to make full use of the growing season, and could be missing out on vital time in the field. It’s no secret that weather is the biggest limiting factor when it comes to timing – so what can we do to help mitigate this?
Know that your planter is ready to go. Having your planter ready is the best piece of advice we can give you as a dealer. If your suitable field work days are already limited, it’s important to not waste any time on setup and repairs that could have been completed during the winter months. Our Van Wall Service Department offers preseason service and inspection specials designed to put your mind at ease and provide a smooth planting season.
High speed is great – when it’s used correctly. While the John Deere ExactEmerge™ planter is way more accurate at higher speeds than conventional systems, it’s important to remember that not every field is suitable for planting this way. The landscape will be a big limiting factor on your speed, but so will the field conditions. Make sure to dig and evaluate your planter passes at higher speeds before completing the whole field. Depending on the soil moisture content, thickness of residue, and ride quality, planting at a higher speed may require more downforce to maintain depth. In the same note, this increased downforce may lead to sidewall compaction and do more harm than good.
- Have as much preseason work completed as possible to limit your downtime when the weather is suitable.
- If using (or considering) an ExactEmerge™ planter, make sure to test passes at higher speeds before committing.
- Even if the weather seems perfect, dig in your trenches after a test pass to make sure the soil conditions are viable.
If you haven’t already, check out Part 1 of our 2021 Seed to Grain Series blog post – we dive more into the agronomics behind choosing the right population for your seed. With a yield impact of 1-2%, choosing the correct population for your acres is an easy way to make sure you’re getting the highest possible return. A population that’s too low limits your yield potential, while putting too many plants on an acre can cause lower yield from a lack of adequate resources.
One rate doesn’t fit all. While variable rate planting is becoming more common every day, it’s important to remember the benefits it can offer. No field has one single soil type, with the exact same conditions across the entire area. So, why would we treat it that way? If you have spots in your field that historically produce less, don’t waste inputs by planting more corn than you’ll yield. On the flip side, take those inputs and redirect them to the areas of the field that are more suitable to handle higher populations while still producing well.
Put the technology to work for you. Today’s planter technology makes it easier than ever to have the best of both worlds when it comes to population. Not only can we use the MyJohnDeere Operations Center to write a prescription before we hit the field (for FREE!), but the electric meters on the ExactEmerge™ mean we can also easily change rates as we’re moving through the field. You only get one chance to plant the field right each year – so make the most of it when it comes to the factors you can control.
- Take the time to evaluate each field’s high- and low-performing areas. Consider writing a prescription to help distribute inputs where they will have the most payoff.
- Even without a prescription, consider changing your seeding rate on-the-go for more broad areas.
When it comes to uniform spacing, John Deere’s ExactEmerge™ BrushBelt™ has changed the game. The yield drop from variable spacing can add up to be a 1-2% impact – and it’s something that we have science to prove is fixable.
Spacing & emergence go hand-in-hand. While uniform spacing alone may not have as large of an impact as uniform emergence, the two factors coincide heavily with each other. If you have plants that are spaced too closely, there’s a good chance they won’t emerge at the same time, as the root systems may begin to compete before they break ground. Plants that are spaced too far apart likely won’t have as many emergence issues, but will leave room for potential loss of sunlight and water during the growing season.
So, how do I fix it? The reason that many growers see a yield bump with the ExactEmerge™ planter is because the BrushBelt™ system takes one key factor out of the game: seed bounce. By hand-delivering each seed directly into the trench, we’ve eliminated the stretch of time where the seed is free falling. If you were to take a seed and drop it into the ground by hand while moving forwards, you’ll notice that the seed will bounce and roll away from the target point. This is (most often) what causes uneven spacing. Because each seed is just a little bit different (shape, size, etc.), they won’t all bounce and roll the same way or distance. With the BrushBelt™ delivery system, your seed is placed exactly where intended for the set population, so you’ll see more uniform spacing and better emergence.
Trust but verify. Regardless of the type of planter you’re operating, it’s important to check your planter performance in the field. Perfect seed spacing distance will vary with the population and row spacing – here’s how to calculate yours:
- 43.56 sq ft / (Row Spacing/12) = Length
- First, we need to determine how many feet in a row are equal to 1/1,000th of an acre. This varies with your row spacing. Take your row spacing width (i.e. 30″) divided by 12 to convert it into feet.
- One acre is equal to 43,560 square feet. Since we’re calculating 1/1,000th of an acre, we can set our square foot area value to 43.56 (43,560 divided by 1,000).
- We know our width and square area – so we need to calculate our length. Take 43.56 divided by your row spacing number (after converting it into feet), and you’ll have your length that is equivalent to 1/1,000th of an acre.
- For 30″ rows, length is 17’5″. For 20″ rows, length is 26’2″.
- Length / (Target Population/1,000) = Target Seed Spacing
- Take the length value from the steps above and divide it by 1/1,000th of your target population. This will tell you how many inches should be between seeds for perfect spacing.
- For example, if we have 30″ rows and a target population of 34,000, we would take 17’5″ divided by 34 – this gives us an ideal spacing of 6.1″.
While you won’t want to dig an entire length of seed trench, measure the distance between 2-3 seeds in a row. This will give you a ballpark idea of how well your planter is spacing the seeds based on your configuration.
- Check your seed spacing a few times in the trench to make sure your planter readings are correct.
- Consider upgrading your planter to an ExactEmerge™ if you feel that uniform spacing is a limiting factor on your fields.
Sources & Supporting Articles
Planting outcome effects on corn yield. Pioneer. https://www.pioneer.com/us/agronomy/corn_planting_outcome_effects.html.
Stand uniformity: planter tips that can impact seed placement and planting depth. Michigan State University Extension. April 12, 2019. https://www.canr.msu.edu/news/stand-uniformity-planter-tips-that-can-impact-seed-placement-and-planting-depth.
Uniform corn emergence tips. Ohio’s Country Journal. February 28, 2017. https://ocj.com/2017/02/uniform-corn-emergence-tips/.
Effects of sidewall compaction on corn seedlings. DEKALB Asgrow Deltapine. March 22, 2021. https://www.dekalbasgrowdeltapine.com/en-us/agronomy/effects-of-sidewall-compaction-on-corn-seedlings.html.
Planting depth is more important than you think. Pederson Seed & Services. April 10, 2019. https://www.pedersonseed.com/post/planting-depth-is-more-important-than-you-think.
Optimum corn planting depth – “don’t plant your corn too shallow”. University of Missouri Integrated Pest Management. April 6, 2016. https://ipm.missouri.edu/IPCM/2016/4/Optimum_Corn_Planting_Depth-Dont_Plant_Your_Corn_Too_Shallow/.