By: Randy Lloyd & Matt Stockton
Background Information
Several University of Nebraska at Lincoln (UNL) specialists grouped together to form a team in the 2023 Subsurface Drip Irrigated (SDI) corn competition of the Testing Ag Performance Solutions (TAPS) program. The following is a short summary of the hybrid and planting population choices made by this team, also known as “The Mighty Morphing Crop Rangers.” Members include Matt Stockton (Ag. Economist Extension Specialist in Farm Management, WCREEC), Randy Lloyd (Agronomist Pesticide Application Lab Research Facility Director, WCREEC), Shannon Sand (Ag. Economist Extension Educator, WCREEC), Xin Qiao (Water and Irrigation Management Engineer Specialist, PREEC), and Gary Stone (Water & Integrated Cropping Systems Extension Educator, PREEC). The competition requires each team or farm to choose a corn hybrid and a planting population for their simulated farm acres. Each team’s three randomly assigned plots total less than half an acre, each representing one-third of the 1,000 acres of their simulated farming operation.
Critical Information
When choosing a corn hybrid and planting population for our team (or for any piece of ground), there are some basic pieces of information needed to best match one of the hundreds of hybrids available from multiple companies to the specific situation where we will be placing our hybrid selection.
Key pieces of information include:
- Yield Goal
- Maturity of Field
- Water Management of Field
- Soil Type/Characteristics
- Field History
- Other
Our team selected Pioneer 1366AML at the planting density of 34,000 per acre. Let’s take each key piece of information and see how it was used to determine a hybrid selection for our team.
Yield Goal
Establishing a yield goal was our first step in determining which hybrid and planting population would be required for our SDI farm. Historical performance is a good way to evaluate the level of expected future performance. Reviewing several years of TAPS data showed a wide range of yield levels, depending on the hybrid chosen and its management in the field. Historically, several plots yielded in the 270 to 300 bushels per acre range across the different, yearly environments. We chose a yield goal of 280 bushels per acre, as a starting point. We assumed the year would at least be average, making it possible for us to attain that level of productivity. The hybrids that reached these levels of yield were typically planted at a population of 32,000 to 34,000. Since we know that we’ll have access to full irrigation, we chose to push the population to the upper end of the range.
Maturity of the Field
Each hybrid has a known number of growing degree days required for its maturity. Knowing the typical growing degree days of the area to be planted helps to match the two, so that the hybrid and field can reach their maximum potential. There may be a reason to choose a corn hybrid maturity other than what specifically fits a field. For instance, if the corn is harvested for silage or wet corn, one may choose a product that has a longer maturing season than typically would be grown, anticipating increased tonnage, and knowing that harvest moisture is intended to be higher. In the case where the harvest needs to be earlier in the season, (e.g., there are lots of acres to harvest), one may choose to use a shorter season product, so that it matures earlier.
In our case, we really want to match our maturity to that of the field we’re planting. In our area, we typically receive enough growing degree units for a 110 to 113-day hybrid. We opted for a 113-day hybrid for full advantage of the average available heat units expected. If we picked a shorter season hybrid, (such as a 100 to 105-day corn), we risk leaving bushels unproduced because we’re not taking advantage of the entire growing season. On the other hand, planting a hybrid that is a longer season hybrid, (120-day), increases the risk of incurring additional drying costs because the corn did not have time to mature and dry in the field – or worse, an early frost killing the plant prematurely with the result of lower yields and poor grain quality.
Water Management of Field
In western Nebraska, there are several types of water management schemes. Dryland (or rainfed) fields typically have a lower yield potential than those that have limited or full irrigation. Some hybrids are a very good choice for dryland but may not have the upside potential when water is more plentiful, such as abundant rainfall or irrigation. It is critical that we look for hybrids that will be able to handle some level of stress, but these plots will be located in a fully irrigated field, so we really don’t have to look for those that have a high level of drought stress tolerance. Since we know that the plots will be fully irrigated, according to our specifications, we decided to push populations a bit to take advantage of a product that has good response to populations. Historically, high yields are typically a response to a higher number of harvestable ears in the field as opposed to fewer ears that are a bit larger. This is due to what is called ear flex, the ability of the plant to alter the size of the ear based on growing conditions.
Soil Type/Characteristics
The competition, including our plots, is located on the West Central Research, Extension & Education Center (WCREEC) home property, which has an average soil type. If, however, there was a special condition, such as heavy clay content, very sandy soil with low water holding capacity, or simply a field with high pH issues, then it would be wise to ask some specific questions about each hybrid before purchasing and planting it in a field. Since our soil doesn’t have any of these concerns, we didn’t look for a product that could handle a specific soil condition.
Field History
Our field/farm for the TAPS competition is under a corn-soybean rotation. That is important because continuous corn may have issues that need to be considered during the hybrid selection process. Emergence and early growth of the hybrid can be affected by heavy residues from a previous year’s high yielding corn. There are disease issues to consider if the field has been in corn for several years. We know that Goss’s Wilt and Corn Lethal Necrosis are both reduced at some level if we break the continuous culture of corn. One of the most common and damaging insect pests in the planting area, Western Corn Rootworm (WCR), can be effectively managed by rotating out of corn, even for a single season. If we don’t have to be concerned with WCR, then we do not need to pick a hybrid with a below ground insect control trait. Hybrids with the trait to control WCR are typically priced a bit higher, so being confident in the value of the rotation effect on WCR, we chose to save a few dollars of our seed costs and opted out of purchasing the trait. Another concern that typically comes up with this type of rotation is the potential for herbicide carryover from the previous year’s soybean crop. In this case, this is not a concern.
Other
While we don’t have a concern about WCR because we are in a rotated field, we do know that the general area typically is plagued with damaging populations of Western Bean Cutworm (WBC). It was decided that we needed to address this possibility. While the TAPS SDI competition provides an in-season option to spray the field for WBC, application timing is critical for solid control and we often miss a few, which will ultimately feed on the ears and reduce our yield. We opted to plant a product that had a trait for WBC control. While this made the seed a bit more expensive, we felt the benefit of having “in-plant” control protecting our yields will outweigh the expense of the trait.
Summary
In addition to knowing some of these critical pieces of information about a field and the characteristics of a hybrid, it’s also good to look at past performance of several hybrids across years with different environments and planting populations. Using this historical yield data from different hybrids at different planting populations helps provide a “pressure test” of a product to know it has worked well under similar circumstances in the past. Each of the discussion points have some element of riskiness associated with them, as conditions and future events are unknowable. Notably, each piece of information relates directly to crop performance and a simple cost-benefit calculation. Bottomline, when considering each of these factoids, one is inherently asking: Knowing what I know, and thinking what I think the season will be, what hybrid selection, planting density, and cultural practices will I follow, so that I can best leverage my resources to accomplish my goals, as a producer?
All of the pieces of critical information discussed here are important in choosing a hybrid and deciding on a planting population, although we know there are still risks. One such risk is the weather. We can mitigate it somewhat by using irrigation, but we still hope for favorable conditions for the 2023 growing season; for our fields and yours.