Creation of Variable Rate Seeding Recommendation
If you are considering Variable Rate Seeding (VRS) for 2025, here is some information you might consider as you build those recommendations. Our Agronomy Field Advisors can provide you with knowledge and direction as Liqui-Grow has the data, and we know how to build recs that will work on your operation!
Corn - How low can you go? Wait, where are you going, and who’s going with you?
Knowledge is king! So, knowing what type of corn hybrid is planted in the field is the first step in deciding on a VRS rec. Another piece of information for VRS decision-making is knowing each field's soil type and yield potential. Some of our modern hybrids have a determinate ear style and will benefit from higher seeding on heavier ground. However, these are also the hybrids you can’t drop too low on populations. Why not? See the table to the right for different ear type explanations!
The majority of the hybrids planted today are semi-flex. Semi-flex hybrids allow flexibility in more challenging soils such as low-yield environments, low CEC, and low organic matter content. In tougher fields, we can lower seeding rates, and use semi-flex hybrids on VRS seeding recs. This allows hybrids to be able to conserve moisture by giving them more space between roots. For example, think of hot dry conditions, and light sandy soils, do you really want to overcrowd that planting environment?
| Determinate (Fixed) |
The corn plant will typically produce the same size (girth/length) ear no matter what population is planted. These hybrids excel in good to excellent soils/fertility and narrow rows when pushed to higher populations. In general, these hybrids flex very little in girth and length but may flex some in kernel depth. |
| Semi-Flex/
Semi-Determinate |
The corn plant will slightly adjust in ear girth and/or length depending on the population planted. These hybrids are the best of both worlds because they won’t give up as much as a flex hybrid in really tough environments, but they can flex some if they have ample water/nutrients. In general, these hybrids flex in at least 2 out of 3 directions. |
|
Flex |
The corn plant will flex a lot and have more length and/or girth at lower populations and when they have ample water/nutrients. They don’t like to be crowded, especially in lower moisture environments. In general, these hybrids can flex in all three directions. |
|
Key: Girth is the rows of kernels around an ear of corn. They will always be in sets of two. Length is the number of kernels down an ear of corn. Kernel depth is how long an individual kernel is from the cob to the tip of the kernel. |
|
Variable rate seeding can help reduce seeding costs on low-return acres and save on your input cost. This is just one example of how Liqui-Grow can evaluate your hybrids and fields to determine what variable rate seeding goals and recs are best for you!
Keep in mind that universities, industry experts and top-yield corn farmers alike stress the importance of placing the right genetics on each field. Liqui-Grow makes placement and population a priority when we build a variable rate seeding recommendation to help you get the most out of those genetics.
By using Liqui-Grow to create your variable rate seeding recommendations, we can couple that with a variable rate nitrogen management recommendation as well. This will allow the correct amount of nitrogen to be applied to the correct population. In other words, we can make sure that you have the right amount of “food” for the party!
Soybeans - here’s the secret…there is no secret.
If you are interested in variable rate seeding for soybean planting, there are a few situations worth trying higher seeding rates. First is lighter, sandy areas. Second would be high pH soils which are oftentimes associated with IDC or iron deficiency chlorosis. Such soil types would be, but not limited to, Harps/Canisteo/Okoboji.
The best strategy would be to evaluate how much yield loss these two issues are potentially causing. If it is a severe issue (greater than 50% yield loss), then it will likely respond to some management techniques, like variable rate seeding. If you only see a slight yield reduction or only on years when the growing conditions are “just right,” then it’s likely not worth it as soybeans can adapt to changing environmental conditions. If that’s all you want to know, call your Agronomy Field Advisor, and get creating those variable rate seeding recommendations! Otherwise, read on!
Soybeans have a large ability to adapt to changing environments and, therefore, can be unresponsive to many management tactics, including variable rate seeding. Under the right conditions, especially if a field consistently shows troubling soybean yields due to any of these factors, it may be worth trying VRS.
Most often, soybeans planted on soils that are lighter or sandier never fully canopy. Anytime you can close the row and reduce evapotranspiration loss, the soybeans stand a better chance of putting on more pods and seeds. In other words, the more rows you have closed, the more yield you can grow! Closing the row also helps with weed control. In these situations, in sandy soil spots, variable rate seeding can push populations up, which means the soybeans have more “inter-row” competition and will force the beans to grow taller, thus having a better chance of closing the rows.
Soybean yields can benefit from variable rate seeding in areas of high IDC potential, especially in the Des Moines Lobe. This is another case where pushing the populations higher can benefit the soybeans.
| High IDC areas are often, high pH, predominantly alkaline soil series, |
Here's Why:
Higher populations crowd the plants and force roots to be closer; roots may even overlap. Those roots change the environment they live in and allow iron to be taken up by the plant and utilized. There are a lot more details to this; we’ll have a blog coming shortly on the IDC topic! - If you’d like to be notified about our IDC Blog post - sign up for our newsletter!
In many cases, growers try to use a soil type map to create variable rate seeding soybean recommendations, however, it would be better practice to use pH from a grid soil sample (preferably 2.5 acres) to establish those areas where IDC are the worst. We can always overlay soil type however those maps were created in the 1960s and are not intended for the accuracy we are trying to use with GPS applications today.
Soybean yield data is not nearly as consistent year to year as corn yield data and doesn’t reveal soil changes as well as corn yield data does. Take the iron deficiency chlorosis problem for instance, it doesn’t always show up in the exact same spot depending on several environmental factors.
Essentially, variable rate seeding soybeans is challenging, but if you have a severe yield-limiting issue like we just discussed, there is a better chance that variable rate seeding could have an impact on your soybean yields. Your local Liqui-Grow Agronomy Field Advisor would be happy to help you figure out if that yield-limiting issue is worth a variable rate soybean recommendation or if another solution is more beneficial.