C.O.R.N. Newsletter: 2022-20
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Nutrient Value of Wheat Straw
Before removing the straw from the field, it’s important farmers understand the nutrient value. This is especially important now with high N, P, and K fertilizer prices. The nutrient value of wheat straw is influenced by several factors including weather, variety, and cultural practices. Thus, the most accurate values require sending a sample of the straw to an analytical laboratory. However, “book values” can be used to estimate the nutrient values of wheat straw. In previous newsletters, we reported that typically a ton of wheat straw would provide approximately 11 pounds of N, 3 pounds of P2O5, and 20 pounds of K2O. According to June 2022 fertilizer prices and nutrient removal “book values”, one ton of wheat straw would remove N, P, K valuing approximately $30.31.
Table 1. What is the value of your straw? N, P2O5, and K2O removed in straw, June 2022 fertilizer prices, and the total value of nutrients within the wheat straw.
N
P2O5
K2O
Removed in straw
11 lb/ton
3 lb/ton
20 lb/ton
June 2022 Price
$1.10/lb N
$1.07/lb P2O5
$0.75/lb K2O
Value
$12.10
$3.21
$15.00
TOTAL VALUE OF REMOVED NUTRIENTS = $30.31 PER TON
The nitrogen in wheat straw will not immediately be available for plant uptake. The nitrogen will need to be converted by microorganisms to ammonium and nitrate (a process called “mineralization”). Once the nitrogen is in the ammonium or nitrate form, it is available for plant uptake. The rate at which mineralization occurs depends on the amount of carbon and nitrogen in the straw (C:N ratio). The USDA reports a C:N ratio of 80:1 for wheat straw which means there are 80 units of carbon for every unit of nitrogen. Mineralization rapidly occurs when the C:N ratio is ≤ 20:1. At a C:N ratio of 80:1, mineralization will be much slower. (For comparison, corn stover is reported to have a C:N ratio of 57:1.) The rate of mineralization is also influenced by soil moisture and temperature. Since mineralization is a microbial-driven process, mineralization will be slowed (halted) in the winter when temperatures are cold. Thus, no N credit is given for wheat straw since it is not known when the N will mineralize and become available to the following crop.
In addition to nitrogen, the removal of straw does lower soil potassium levels. If the straw is removed after heavy rainfall, some of the potassium may have leached out of the straw, lowering the nutrient value. However, a soil test should be done to accurately estimate nutrient availability for future crops. Besides providing nutrients, straw has value as organic matter, but it is difficult to determine its dollar value.
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Double-Crop Soybean Weed Management
It’s been a tough summer in parts of Ohio to do anything on a timely schedule and there are some weedy fields. The best advice we have for big weeds in full-season soybeans is to increase rates and the complexity of POST herbicide applications, while still adhering to cutoffs for the application of certain herbicides as much as possible. Dicamba products, XtendiMax, Engenia, and Tavium, cannot legally be applied to Xtend and XtendiFlex soybeans after June 30. This cutoff date pertains to use in double-crop soybeans also. If you are planning on planting Xtend or XtendiFlex soybeans in double-crop fields and using dicamba as a burndown, apply before Friday. There isn’t a cutoff date for most other POST soybean herbicides – it’s based on either crop stage (eg R1) or days before harvest.
Double crop soybeans usually need some type of weed control program, although how weedy they get depends upon weeds surviving down in the wheat that can take off once they receive light; how much rain we get in July, which drives additional weed emergence and rate of soybean growth; and how fast the soybeans grow and develop a canopy. Control can occur via the use of pre-plant/preemergence burndown herbicides, followed by POST as needed. It’s also possible to accomplish this with one early POST application in Enlist soybeans, using Enlist Duo or a combination of Enlist One with glyphosate or glufosinate. And also in LLGT27 soybeans with a combination of glyphosate and glufosinate. Herbicides need to address marestail in many fields, which is often lurking in the wheat ready to regrow. Marestail that are taller and get cut off by the combine will be more difficult to control than the smaller intact ones below the cutter bar. Herbicide options vary depending upon the weeds and what type of soybeans are planted. More effective options include:
- Glyphosate or glufosinate + Sharpen (1 oz) + MSO – any soybean, prior to emergence
- Glyphosate or glufosinate + 2,4-D – any soybean, at least a week before planting
- Enlist Duo; glyphosate or glufosinate + Enlist One (Enlist soybeans) – PRE or POST, no wait to plant
- Glyphosate + XtendiMax or Engenia (Xtend or XtendiFlex soybeans) – PRE, apply by June 30
- Glyphosate + glufosinate – PRE in any soybean, PRE or POST in LLGT27 soybean
It is possible to include residual herbicides with a PRE burndown treatment, but their value in this situation is questionable. Residual herbicides with long recrop intervals to corn should be avoided. POST options in double-crop include glufosinate, glyphosate, Enlist One/Duo, and conventional herbicides, depending upon the type of soybean planted. One caution here is to avoid excessive injury to soybeans that slows growth and development since this is likely to reduce yield due to the short season. Weed emergence is reduced and variable in July compared with May and June. Where burndown herbicides are used, but there is still a need for POST herbicides to control a flush of late-emerging weeds, consider reduced rates. Research we conducted back in the 1990s demonstrated that weeds up to 2 inches tall can usually be controlled with half of a typical labeled rate. When we planted soybeans in early June, the single application of a half-rate provided adequate control, versus early May when a second application was needed. So this should be a suitable approach for double-crop soybeans. Just be sure to start with an effective burndown at planting, and apply when weeds are well within the 2-inch size.
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Lep Monitoring Update WBC, CEW, and ECB Updates
Western Bean Cutworm
Western bean cutworm (WBC) traps were set the week of June 13th and the first trap captures were reported for the week of June 20th through June 26th. Reported moth numbers were low in all counties this past week with only three of the 13 counties reporting moths (Figure 1).
Western Bean Cutworm moth map
June 20 – 26, 2022
Figure 1. Average western bean cutworm (WBC) moths were captured from June 20th through June 26th. The large number indicates the average moth count for the week and the small number in parentheses is the total traps set up in the county.
Corn Earworm
Corn earworm (CEW) (Figure 2) numbers have gone up this past week. Two counties (Putnam and Van Wert) reported averages above 20 moths per trap (Figure 3). Moths are most attracted to silking corn, where eggs are laid and the caterpillars damage developing corn. Corn earworm is more commonly associated as a pest of sweet corn, but it is possible to find CEW in field corn. Monitoring for CEW will continue through August. For more information on corn earworms: https://agcrops.osu.edu/newsletter/corn-newsletter/2019-27/corn-earworm-field-corn-watch-molds
Figure 2. Corn earworm (CEW) moth with wings folded at rest. Photograph by Jessi Raubenolt.
Corn Earworm moth map
June 20 – 26, 2022
Figure 3. Average corn earworm (CEW) moths were captured from June 20th through June 26th. The large number indicates the average moth count for the week and the small number in parentheses is the total traps set up in the county.
European Corn Borer
European corn borer (ECB) reported moth numbers remained low over the past week with no reports of ECB-IA and only two counties (Hardin and Muskingum) reporting ECB-NY (Figure 4).
European Corn Borer moth map
June 20 - 26, 2022
Figure 4. Average European corn borer (ECB) moths were captured from June 20th to June 26th. The first number indicates the average ECB-IA followed by a comma and then the average ECB-NY moth count for the week. The small number in parentheses is the total traps for each species set in each county.
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Supplemental Forages to Plant in July After Wheat
Some producers may be considering planting a supplemental forage crop after winter wheat grain harvest for various reasons. Some areas of the state are becoming very dry. In many areas, the wet weather this spring resulted in ample forage supply, but good to high-quality forage is in short supply because of the wet weather that delayed harvesting until the crop was mature, or it resulted in rained-on hay that lowered quality.
The table below summarizes options for planting annual forages after wheat harvest.
Species
Comments
Corn plant silage
Highest single-cut forage yield potential of all choices.
Silage quality will be lower than normal planting dates.
The risk is getting it harvested at the right moisture for good fermentation.Forage sorghum
Sorghum-sudangrassSudangrass
Best harvested as silage.
Brown midrib (BMR) varieties have higher digestibility and are best for growing animals and lactating cows; however, conventional varieties are okay if BMR seed is not available. Can produce 3-4 tons of dry matter/acre. Potential high nitrates under drought conditions. Risk of prussic acid (hydrogen cyanide gas) if frosted.
Soybean silage
A reasonable alternative to replace alfalfa forage. Check seed treatment and herbicide labels, many restrict forage use.
Teff grass
Best suited to beef and sheep; lower yield than sorghum grasses.
Can be harvested as hay or silage.
Millets
Best suited to beef and sheep; many produce a single harvest.
Best harvested as silage. Potential high nitrates under drought conditions. Pearl millet has no prussic acid after frost damage.
Mixtures of annual grasses with soybean
Best harvested as silage.
Mixtures of sorghum grasses or millets or even oats and spring triticale with soybean are feasible and soybean can improve forage quality characteristics.
The forage grass options all require adequate nitrogen to maximize yield potential, either as fertilizer or manure (about 60 lbs of actual available nitrogen per acre). Check any potential herbicide restrictions from the previously planted crop and consider herbicides used after wheat and before planting these annual forages.
Chopping and ensiling or wet wrapping are the best mechanical harvest alternatives for most of the options listed. Wilting is usually necessary. Storage and harvest costs are greater, and fermentation quality can be poor with crops less than about 30% DM (greater than 70% moisture). Ideally, silage should be left undisturbed for at least two weeks to allow the forage to reach stable fermentation. If forage is needed sooner, consider daily green chopping of forage or wet wrapping individual bales for feeding until the silage is ready. Except for Teff, dry baling any of the listed forages is a challenge. Work with your nutritionist to incorporate these alternative forages into properly balanced rations.
In addition to these options, Italian ryegrass or oats can be planted in early August, if soil moisture is adequate. They will produce forage into the autumn months, and Italian ryegrass will likely survive the winter and produce forage next spring and early summer depending on the variety planted. They are suitable for ensiling or wet wrapping or grazing in the autumn. Brassicas can be planted in early August as well, but they are only suitable for grazing in the autumn, not for mechanical harvesting.
For more information see the following:
https://forages.osu.edu/forage-management/forage-species-varieties/annual-forages
Consult the Ohio Agronomy Guide for management details, available at https://extensionpubs.osu.edu/ohio-agronomy-guide-pdf/
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Manure Science Review Coming July 26th
The annual Manure Science Review (MSR) will be held on Tuesday, July 26th from 9:00 am to 3:00 pm at the Ohio Agricultural Research and Development Center Northwest Station near Hoytville. The address is 4240 Range Line Rd., Custar, OH 43511.
Attendees will explore presentations about H2Ohio: Current Status and Future Plans from Terry Mescher, H2Ohio Program Director, ODA Division of Soil and Water Conservation, Beaver in a Bag: Creating Mini-Wetlands to Control Runoff from the Putnam SWCD office, Composting Pen Pack Cattle Manure for Improved Nutrient Transport from Jordan Beck, Understanding Manure Analysis – Comparison to Commercial Fertilizer from Glen Arnold, and Experience with Variable Rate Manure Application-Duane and Anthony Stateler, Stateler Family Farms
In the afternoon there will be demonstrations of solid and liquid applicators, the Cadman Side-dress System, Oxbo Equipment, in-season manure side-dress demos, drones for cover crop seeding, and more.
Continuing education credits will be available for Certified Crop Advisors (CCAs) and Certified Livestock Managers (CLMs). Registration costs are $25 per person until July 15th and $30 per person after that date. For program and registration details, click on the links below or contact Mary Wicks (wicks.14@osu.edu; 330.202.3533).
Program and registration details: click here
Online registration: click here
Sponsor & exhibitor opportunities: click here
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Tri-State Precision Agriculture Conference
The second annual Tri-State Precision Agriculture Conference will be held at Northwest State Community College in Archbold, Ohio on July 27, 2022. This year’s event will highlight sprayer and pesticide application technology. The morning sessions will feature presentations on Best Practices for Efficient Application of Pesticides by Erdal Ozkan, Professor Department of Food, Agriculture, & Biological Engineering Ohio State University; How to Manage Sclerotinia White Mold in Soybeans by Michael Staton, Soybean Educator Michigan State University; Managing Tar Spot in Corn by Pierce A. Paul, Professor Cereal Pathology, Epidemiology Ohio State University.
During the event, a hands-on sprayer demonstration featuring sprayer calibration, deposition, drift from different nozzles, spray uniformity, and boom movement. The afternoon will feature technology demonstrations from manufacturers such as John Deere, Hagie, Case IH, Hardi, and many more. Demonstrations on current UAS "Drone" spraying technology will also be featured. Several agribusinesses will be featured in the trade show area including the field demonstration companies. Private Pesticide Applicator credits (PAT) and Certified Crop Advisors (CCAs) recertification credits will be available. You may register for the event at https://go.osu.edu/henryanr2022. If you would like more information, please contact the Henry County Extension Office at 419-592-0806 or email at leininger.17@osu.edu.
Crop Observation and Recommendation Network
C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.
Contributors
Disclaimer
The information presented here, along with any trade names used, is supplied with the understanding that no discrimination is intended and no endorsement is made by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.
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