Test weight and grain quality have been a popular topic of discussion on social media lately. At Hoegemeyer, we take great discussions like this to heart and want to provide information on test weight in corn to use in your next discussion on this topic.
Grain yield and kernel test weight are typical parts of the cafe discussion around hybrid selection in the winter or corn harvest in the fall. Test weight also factors into the price at the elevator when discounts are applied for delivered grain that weighs less than 56 lb/bu. While the terms bushels and test weight are bantered around, it might be worthwhile to dig into these terms and compare their importance at the elevator compared to the feed mill (or total mixed ration mixer).
Low test weight causes
Test weight helps account for the varying densities of grain caused by weather and/or production practices. There are many causes of reduced kernel fill including hybrid genetics, low temperatures, reduced solar radiation (cloudy conditions), premature death due to leaf disease, ear rots, drought and freeze damage to late-developing fields.
When kernels are prevented from filling completely and/or maturing and drying naturally in the field, the starch molecules inside the grain are prevented from the natural process of shedding absorbed water molecules that allows the grain to shrink to a normal size. Artificial drying with heat removes this excess water but the starch molecules do not shrink, and grain size doesn't change appreciably, so test weight remains relatively low.
In some situations, mature kernels significantly hydrated by rain, dew or fog can initiate early germination in the field during which starch is utilized for energy leaving small voids inside the grain. Although the grain may again dry in the field, the seed size does not change, and the small voids inside the seed can result in a decreased test weight.
Test weight for a given hybrid can vary from field to field and from year to year and does not correspond very well to the yield potential of the environment. Data from Purdue University shows the lack of correlation between grain yield and test weight in nitrogen rate trials over multiple site-years in Indiana.
Transportation and storage
At the elevator, 1 bu. of corn is defined as 56 lb. independent of test weight. The weight of the corn for which a seller is paid is, therefore, not affected by test weight - 56 lb. is 56 lb. However, the price the seller receives for a bushel can be affected by test weight. Transporting and storing lower bulk-density grain is more expensive (on a weight basis), so buyers discount grain on a sliding scale if test weight is below minimum standards.
Higher weight per unit volume of grain has obvious advantages in harvest, handling and storage: More bushels will fit in the combine grain tank, on a truck or in a grain bin.
Kernel moisture and test weight are inversely related with higher moisture kernels displaying lower test weight. As corn dries in the field or in a dryer, test weight naturally increases if kernel integrity remains intact. Test weight increases because dried kernels shrink and are slicker so tend to pack more tightly in a quart cup. Kernels are also denser than water, so bulk density goes up as water exits the kernel.
While it is true that test weight will increase due to natural or artificial drying, the increased test weight means the corn will occupy less total volume because of increasing the corn bulk density and could potentially reduce test weight dockage at the elevator. It does not mean there will be any more bushels (pounds) to sell because 1 bu. is 56 lb. regardless of test weight.
When the growing season produces low-test corn, it is important to feed corn based on weight and nutrient content and not volume such as bucket loads.
Research on feeding light-test weight corn to dairy cattle is lacking. However, there is a considerable body of research from beef cattle showing that moderately low-test corn (46-48 lb/bu.) results in similar daily gain and feed efficiency to normal corn. This supports an early study from Minnesota showing very little difference in the gross energy of corn ranging from 35 lb to 56 lb/bu.
Due to a lowered starch dilution effect, light-test corn will be higher in crude protein and fiber, so analyzing nutrient content and using modern summative net energy equations may be the best way to determine feeding rates.
Research supports the sage advice of selling high-test weight corn and feeding low-test corn. While test weight, a measure of grain bulk density, has important implications for pricing at the elevator and transportation/storage costs, it has less significance for feeding the grain to ruminants.
The primary watch-outs for feeding light-test corn include a tendency for faster ruminal starch digestion rates, monitoring for mycotoxin levels, the need to feed by weight not volume and close attention to processing consistency.
With the recent announcement of Chinese-approval of the Enlist E3™ soybean trait, many farmers are anxious to learn more about this new technology. The Enlist E3 soybean trait technology gives you options to control weeds that you have never seen before. With resistance to three different herbicides, (2,4-D Choline, Glufosinate and Glyphosphate,) you have the flexibility to use multiple options in your herbicide program throughout the growing season.
Along with Glyphosphate and Glufosinate herbicide resistance, Enlist soybeans also have a resistance to a new herbicide formulation known as 2, 4-D Choline, also known as Enlist. Although a different formulation from the old ester and amine 2, 4-D herbicides you may be used to, it works similarly as a Group 4 PGR.
The application window is much larger with the Enlist system than expected. Enlist may be sprayed on soybeans up to the R2 stage, and there is no buffer when sprayed against non-susceptible crops (including non-Enlist soybeans.) It is advised not to spray at all when the wind is blowing toward susceptible crops including but not limited to cotton, grapes, and tomatoes.
Wind speed recommendations are between 3-10mph, and when temperature inversion is unlikely. Some states have adopted more rules concerning wind speed, consulting with state laws in your area is recommended. Application rate of Enlist One is 2 pints/acre, while Enlist Duo is 4.75 pints/acre. Enlist herbicide is also NOT an RUP (restricted-use pesticide.) Nozzle recommendations, tank-mix partners, and crop info is available at www.enlist.com.
Driving through the county this fall, you might have seen a lot of fields where crop residue was baled. Baling crop residue can be a way to bring more income to the farm in lean years, but will it pay off in the long run? Let’s look at the pros and cons of baling residue to see if it is a fit for your farm.
Increased income per acre.
In corn-on-corn fields, you may see increased yields as well as decreased foliar disease pressure (most foliar diseases are residue-borne meaning next year inoculum comes from infested corn residue).
And if you have livestock, you can use residue for feed as well as bedding.
These factors making baling seem like a good plan but what could you be losing by baling crop residue?
Baling residue does cost in labor, time and money (raking, baling, and moving bales).
When you haul residue off a field, you are hauling nutrients and organic matter off the field as well. Table 1 shows approximately how many pounds of Nitrogen, Phosphorus, Potassium and Sulfur you are removing when residue is taken off a field. If you remove 4 ton/acre of corn residues, you are removing 68 lbs./acre Nitrogen, 16 lbs./acre Phosphorus, 134 lbs./acre Potassium, 12 lbs./acre Sulfur and many other nutrients in lesser amounts. If you remove this residue, you need to have a plan to replace it, whether that be through a manure application or synthetic fertilizers.
In addition to nutrient loss, you also are losing organic matter. If you continue to remove residue, eventually you will begin to deplete organic matter on these fields. Organic matter is important for nutrient cycling, water holding capabilities of a soil, and water infiltration.
Erosion control is a final consideration for whether baling residue is for you. If residue is needed, pick fields where wind and water erosion are less of a concern. On steep slopes, leave residue cover and choose fields with heavier soil types to minimize wind erosion through the winter and spring.
Summary: Consider the pros and cons above and the chart below to see if removing residue from your fields might be cost-effective in the long run. The bottom line is if residue is removed from a field, you need to make sure those nutrients are replaced in one way or another.
Source: UNL Cropwatch. What is the value of soybean residue? December 13, 2018
It is that time of year to sit down and evaluate the agronomic practices we did in 2018. We ask ourselves many questions trying to learn what worked and what we could do better in 2019.
Did we apply enough nitrogen?
Am I applying enough fertility?
Did cover crops work?
AND of course, did my hybrids meet my expectations?
Demonstration plots can help growers evaluate hybrids over a wide range of soil types, weather patterns and tillage practices. I would consider the following traits when examining hybrid demonstration plots.
Diseases: 2018 was a great year to evaluate disease resistance. Diseases will start hitting the plant the hardest during the grain fill period causing serious yield reductions from leaf diseases, ear rots and stalk lodging problems. Photosynthesis is the fuel to supply the plant energy for grain fill and plant health. Leaf disease will limit the amount sunlight it can capture and limit yield. Walking plots and your own fields gives you an opportunity to compare the differences among hybrids to disease problems that have occurred in your area. The environment over the last 5 years has created in many regions a concern over late season plant health. This is also a great time to try a foliar fungicide and see how it improves plant health of certain hybrids. Look at a nice mix of hybrids and fungicides in your future hybrid selections.
Lodging: Every year is a good year to evaluating stalk strength scores in your area. Right prior to and during harvest is a good time to assess stalk and root lodging. Environmental conditions along with planting populations can affect stalk and root lodging. Once lodging is noticed pay attention to the timing of the incident and do some more evaluation to determine what caused the event. Early root lodging could be caused by rootworm activity. Later root lodging could be caused by disease or stress from drought, excess heat or excess water. Stalk lodging is general a cause of wind, drought, hail and could be from high populations. If any of these stresses occur on a regular basis in your area, refer to the stalk strength scores in the seed guide because they may give you an insight of performance.
Population: Higher and lower plant populations will affect standability and yield. Certain hybrids have more of a fixed ear type, this means that the plant needs and can be planted at higher populations to achieve the desired yield goal no matter what the environment is. Other plants are a flex type ear which enable the plant to determine yield based off environmental conditions. The better the environment the bigger the ear the plant will produce. These hybrids are generally planted at lower populations. Please make sure that population charts are followed and setting the correct population for the hybrid and field is important. Most plots are planted at the same population, this needs to be taken into consideration when evaluating the plot yield results. An example of this would be if a hybrid with a fixed ear type is planted in a low population plot then hybrids with a flex ear type may have an advantage.
At Hoegemeyer, we are proud of the in-house agronomy research that we provide to farmers to help educate their farming decisions. We continue our extensive work on corn population studies and test our current line-up along with new experimental hybrids coming down the pipeline to maximize your seed investment. Learn more about planting populations here.
Plant and Ear Height: The corn plant reaches its maximum height around tassel time. If you are prone to wind events, plots are a good tool to help make hybrid decisions. A tall plant with a high placed ear is more susceptible to stalk lodging. Also, if you have soil type variances in your fields, you will want to focus on hybrids that have a higher ear placement. Plant type does need to be considered in your decisions for such things as residue management, field variability and cropping preferences such as silage.
Yield Potential: Of course, YIELD is one of the first things that should be considered. When looking at yield make sure you look at more than one plot, make sure those plots have checks or are replicated to smooth out soil variability. Don’t always pick the plot winner! Consistency is the key, look for hybrids that seem to always be in the top 5 in many different plots. Make sure you match up appearances with results, the prettiest one doesn’t always win. Make sure to check on ear appearance. Does it have molds, how many kernels around, how much tip back is there and how many kernels on the ear? Just to name a few.
Contact your local Hoegemeyer dealer to help you evaluate test plots and pick the right seed for your acres.
The 2018 harvest had many challenges! One of the biggest challenges was an abundance of moisture. When there’s heavy precipitation in the fall, harvest can be challenging. Farmers need to consider how to get in the field to harvest, and if time allows, complete some fall tillage.
Soil compaction is a concern when operating implements on wet soils. Consider using these strategies to limit soil damage and help fields dry out in the spring for quicker planting.
How do we fix the ruts we made?
Many of us had to go against our better judgement in the wetter spots in our fields. If you have ruts in the field from harvest, your gut tells you to aggressively fill them in. Take step back and ask yourself, is this what’s best for my soil structure? Soil structure is your soil’s number one defense against future soil compaction, and tillage destroys structure.
To fill in your ruts and maintain your soil structure, use light tillage by running equipment at an angle. Use multiple passes if necessary. These areas will need time to recover and yield has the potential to be affected compared to the non-rutted areas.
Is deep tillage the answer for wet spots I couldn’t harvest?
Disking and vertical tillage I believe are the best options for introducing air into the soil. A light pass no deeper than 3” if the soil is wet will incorporate residue and help prepare the soil for next year. Vertical tillage fluffs up the remaining residue with shallow penetration and minimal movement of the soil. Clods are created from ripping wet soils too deep with a chisel plow of disk ripper. If you use these types of implements, shallow up the shanks and use narrower points to avoid creating clods.
Can I use tillage after frost?
There was research completed by Harold van Es and Robert Schindelbeck done in 1993 on tillage on slightly frozen ground. Here is what they found: Compared to no frost, they found when the frost layer was .5” to 1”:
The soil better supported the equipment’s weight when chisel-plowing to a depth of 8”.
The soil below the frost layer was drier and tilled easily.
Corn yields weren’t affected
Moisture infiltrated quicker in the tilled soil vs. a soil without tillage. This is due to the frozen plated of soil created with frost tillage, as these plates thawed, they quickly diminished.
Make sure you plan ahead for spring this fall, or what’s left of it. Tillage after the frost is very time sensitive and takes more horsepower.