C.O.R.N. Newsletter: 2022-36
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Weather Update: A Winter Preview Before Warmer Weather Returns
Summary
A strong cold front brought beneficial rainfall to many areas along and east of about I-71 last week. However, parts of western Ohio missed out on much of the activity, as very dry conditions continue across that part of the Buckeye State. Over the last 30 days, parts of Darke, Preble, Montgomery, Miami, and Shelby Countes have picked up less than 5% of their normal rainfall for this time of year (Figure 1). Dayton, Ohio has seen its second-driest stretch for the last 30 days (0.1”), just behind the record set in 1963 (0.05”). Dry, windy conditions led to several reports of combine and field fires, including a fairly large incident in Darke County. On the flip side, wet condtions continue near Lake Erie in northeast Ohio. Overall, temperatures continue to run below average as well, 1-3°F below average across much of the
southern half of Ohio. For the latest up-to-date conditions, seasonal outlooks, and monthly climate summaries, please visit the State Climate Office of Ohio.Forecast
The first half of this week will be dominated by an upper-level low pressure system that will move through the Great Lakes, bringing with it blustery conditions, cold temperatures (15-20 degrees below normal), and the chance of rain showers mixed with snow at times. Freeze Warnings and Watches are also in effect, as overnight lows through Thursday morning are likely to flirt with or drop below freezing. This will likely end the growing season across the state. Highs through Wednesday are only expected to top out in the mid to upper 40s at best. Conditions will start to impove on Thursday, with sunshine returning and highs in the low to mid 50s. Dry weather is expected to continue on Friday and throughout the upcomiong weekend. Southerly flow around high pressure will lift highs back into the 60s and eventually 70s. The Weather Prediction Center is currently forecasting up to 0.50” of precipitation across Ohio this week, with locally heavier amounts downwind of Lake Erie (Figure 2).
The Climate Prediction Center’s 6–10-day outlook for the period of October 23 - 27, 2022 and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center show a major weather pattern shift, with above normal temperatures likely and precipitation near or leaning above average (Figure 3). Climate averages include a high-temperature range of 61-65°F, a low-temperature range of 41-44°F, and average weekly total precipitation of 0.55-0.75 inches.
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Watch for potential frost damage to non-mature corn
In Ohio, October usually brings our first fall freeze. On October 11, USDA reported that 15% of Ohio’s corn grain had been harvested (week ending 10/09/2022, full report here). In the same report, 96% of corn was at the dented stage, and 71% was mature. With additional sub-freezing temperatures possible this week, the potential for yield losses due to frost damage exists for any standing crop that has not matured yet (i.e., not reached physiological maturity).
Sub-freezing temperatures (<32°F) were reported at numerous sites across the state during the early morning hours of October 8-9. This includes the Western Research station (located in Clark County, Ohio), as documented by the CFAES Ag Weather System. Temperatures that can cause frost damage to non-mature corn are:
- Temperatures close to 32°F for a few hours
- Temperatures close to 28°F for a few minutes
At Western, the air temperature dropped below 32°F for more than 6 hours over the two nights, with more than 2 hours spent below 30°F. What damage can one expect from freezing conditions on a standing crop that has not yet matured?
Frost damage symptoms to corn are shown in Figure 1. These symptoms can be seen a few days after freezing takes place. However, it is recommended to wait 5-7 days to assess the damage and have a clearer view of what was damaged by frost versus what was not. Premature assessments have the risk of underestimating the magnitude of damage and loss.
Figure 1. Non-mature frost-damaged corn. Pictures: Jenny Rees, University of Nebraska, 2022.Research has estimated yield losses in corn (Table 1, using 80- and 105-day hybrids); Afuakwa and Crookston (1984) reported:
Early dent stage (R5): if leaves and stalks are frost damaged, a 40% yield loss can result. If only leaves are frost damaged, a 25% yield loss can result.
Half milk-line stage (R5.5): if leaves and stalks are damaged, a 12% yield loss was observed. If only leaves were damaged, a 5% yield loss was observed.
Table 1. Potential grain yield losses after frost. Adapted from Afuakwa and Crookston (1984).
Corn Development
StageKilling frost
(Leaves and stalk)Light frost
(Leaves only)percent of yield loss (%)
R4 (Dough stage)
55
35
R5 (Dent stage)
40
25
R5.5 (Half milk line)
12
5
R6 (Physiological Maturity)
0
0
In a corn crop with frost damage, a black (or brown) layer will eventually form on the kernels when there is no more movement of nutrients. Frost damage corn can result in lower test weight, sometimes called chaffy ears. Low test weights can reduce storage life; additional steps can be taken to minimize further losses (e.g., more/better aeration, gentle drying, careful and timely handling). Kernels undergoing the natural maturation process will contract and harden their coat after maturity, but this process can be disrupted by early death. The coats may be more prone to breakage and could produce more fines during harvest from broken kernels.Due to the premature disruption to proper crop growth and development, early terminated corn will have higher kernel moisture content and take longer to dry, partly due to natural senescence being disrupted and disrupted husk leaf maturation. Ears with loose husks dry more rapidly than those with tight or normal husks; forced death from cold can impede the natural senescence process of husk leaves. Plans for grain drying and delivery should account for that extra time.
Besides low temperatures, situations that can be conducive to frost damage include fields that were planted (or replanted) late and fields that were planted to longer or full-season hybrids. If frost damage is a concern, consider to:
1) monitor crop standability
2) scout for stalk rots
3) watch for the potential of ear dropIf the latter is happening, one may need to consider harvesting the field earlier (although at higher moisture) and explore alternative market opportunities if necessary.
Resources
Afuakwa, J.J., and R.K. Crookston. 1984. Using the kernel milk line to visually monitor grain maturity in maize. Crop Sci. 24:687-691. https://doi.org/10.2135/cropsci1984.0011183X002400040015x
Carter, P.R., and O.B. Hesterman. 1990. Handling corn damaged by autumn frost. Available at: https://www.extension.purdue.edu/extmedia/NCH/NCH-57.html
DeVries, M., Goggi, A.S., and Moore, K. 2007. Determining seed performance of frost-damaged maize seed lots. Crop Sci. 47:2089-2097. https://doi.org/10.2135/cropsci2007.01.0005
Hicks, D.R., Geadelmann, G.L., and Peterson, R.H. 1976. Drying rates of frosted maturing maize. Agronomy Journal 68:452-455. https://doi.org/10.2134/agronj1976.00021962006800030004x
Licht, M., and Hurburgh, C. 2019. Harvest consideration for frost-killed corn. https://crops.extension.iastate.edu/blog/charles-r-hurburgh-mark-licht/harvest-consideration-frost-killed-corn
Nielsen, B. 2019. Frost or freeze damage to immature corn. Available at: https://www.agry.purdue.edu/ext/corn/news/timeless/FrostFreezeImmatureCorn.html
Rees, J., Cafaro La Menza, N., Specht, J., Beckman, B., and Schick, B. 2022. Premature Frost Damage to Crops. Available at: https://cropwatch.unl.edu/2022/premature-frost-damage-crops
Thomison, P. 2019. Late-season Frost Effects on Corn: Grain Production. Available at: https://agcrops.osu.edu/newsletter/corn-newsletter/2019-33/late-season-frost-effects-corn-grain-production-adapted-dr-j
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2022 Ohio Soybean Performance Trials- South Region Results Available
Results for the 2022 Ohio Soybean Performance Trials are available for the South Region (Preble and Clinton County): https://stepupsoy.osu.edu/sites/hcs-soy/files/2022_OSPT_South%20Region.pdf We will continue to update this report as additional locations are harvested.
The purpose of the Ohio Soybean Performance Trials is to evaluate soybean varieties for yield and other agronomic characteristics. This evaluation gives soybean producers comparative information for selecting the best varieties for their unique production system. In the South Region, the average yield was 67.0 and 77.2 bu/acre in Preble County and Clinton County, respectively, for the early maturity trial (2.9-3.6). The average yield was 67.1 and 75.6 bu/acre in Preble County and Clinton County, respectively, for the late maturity trial (3.7-4.3).
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Increase Your Seeding Rate For Late-Planted Wheat
In general, the best time to plant wheat is the 10-day period starting the day after the fly-free safe date. When wheat is planted more than 10-days after the fly-free safe date, there is an increased chance of reduced fall growth and winterhardiness, but the same yield may be achieved as earlier planted wheat if freezing weather does not occur until late November or early December. However, a higher seeding rate is recommended. According to the Ohio Agronomy Guide, for wheat planted 3-4 weeks after the fly-free-safe date, a seeding rate of 1.6 to 2.0 million seeds per acre should be used.
Our recent research trial in Wood County supports the wheat seeding rate recommendation found in the Ohio Agronomy Guide (Figure 1). In Wood County, there was no effect of seeding rate when wheat was planted six days prior to or six days after the county fly-safe date. However, when wheat was planted 29 days after the fly-safe date, a seeding rate of 1.5 million seeds/acre was needed to achieve the same yield as earlier planted wheat. At 48 days after the fly-safe date, a seeding rate of 2.0 million seeds/acre was needed to achieve the same yield as earlier planted wheat. (This trial is funded by Ohio Corn and Wheat, and we will repeat the study during the 2022-2023 growing season.)
Keep in mind, the actual number of seeds per pound and germination rate are important for determining the correct seeding rate and drill calibration (Table 1). There are fewer seeds per pound of large seeds than pounds of small seeds. The number of seeds per pound can be found on the seed bag. Additionally, late planting also means plants will be smaller than normal when entering dormancy and have smaller, more shallow root systems, making them more susceptible to heaving next March. The best heaving control is to get the seed placed between 1.0 and 1.5 inches deep when planting and to plant no-till. These two practices combined will reduce heaving potential.
Table 1. Pounds of seed needed to plant from 1.2 to 2.0 million seeds/acre with seed of varying size.
Millions of Seeds/Acre
Seeds/lb
1.2
1.4
1.6
1.8
2.0
10,000
120
140
160
180
200
11,000
109
127
145
164
182
12,000
100
116
133
150
167
13,000
92
108
123
138
154
14,000
85
100
114
129
143
15,000
80
93
107
120
133
16,000
75
88
100
113
125
17,000
71
82
94
106
188
18,000
66
77
89
100
111
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The War Against Weeds Podcast
The War Against Weeds Podcast is back for season four! We’re in the midst of harvest which means endless cab hours, what better time to start a new series? Tune in to hear Sarah Lancaster (Kansas State University), Joe Ikley (North Dakota State University), and me as we chat with weed science and agronomy experts to discuss all things weed control.
In this season we cover a range of topics, everything from crop injury to combine cleanout. Each episode is approximately 30-40 minutes long and features a different guest expert on the topic at hand. To binge the previous three seasons and catch up on the fourth, find us on your preferred podcast provider - Spotify, Google Podcasts, iTunes, or online. We can also be found on the Crop Protection Network website, along with other crop protection resources including webinars, web books and newsletters.
To help us provide a better listening experience, please consider filling out this survey. It takes less than 5 minutes, and we’d greatly appreciate any feedback.
Silver bullets are for werewolves, not weed control…happy listening!
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Fall Sprayer Maintenance
Proper winterizing and storing your sprayer now help you mitigate costly problems in the spring
It is very likely that you will not be using your sprayer again until next spring. If you want to avoid potential problems and save yourself from frustration and major headaches next spring, you will be wise to give your sprayer a little bit of TLC (Tender Loving Care) this time of the year. Yes, there may be still crop to be harvested, and you may still be a busy time of the year for some of you. However, do not forget about winterizing your sprayer. Do not delay it too long, if you already have not done so. You don’t want a pump that is cracked and/or not working at its full capacity because you did not properly winterize it before the temperature falls below freezing. Here are some important things you need to do with your sprayer this time of the year.Rinsing
It is very likely that you did the right thing when you used the sprayer the last time: you rinsed the whole system (tank, hoses, filters, nozzles) thoroughly. If you did not, make sure this is done before storing the sprayer. A sprayer that is not rinsed thoroughly after each use, and especially after the spraying season is over, may lead to cross-contamination of products applied for different crops next spring. Pay even more attention to avoid cross-contamination problems that may result in serious crop injury if you are using some of the new 2,4-D and Dicamba herbicides. Another problem that may result from lack of, or insufficient rinsing of the complete sprayer parts is clogged nozzles. Once the nozzles are clogged, and they remain in that condition a long time, it is extremely difficult to bring them back to their normal operating conditions you expect from a comparable clean nozzle. Leaving chemical residues in nozzles will usually lead to changes in their flow rates, as well as in their spray patterns resulting in uneven distribution of chemicals on the target.Depending on the tank, proper rinsing of the interior of the tank could be easy or challenging. It will be very easy if the tank is relatively new and is equipped with special rinsing nozzles and mechanism inside the tank. If this is not the case, manual rinsing of the tank interior is more difficult, and poses some safety problems such as inhaling fumes of leftover chemicals during the rinsing process. To avoid these problems, either replace the tank with one that has the interior rinse nozzles, or install an interior tank rinse system in your existing tank.
For effective rinsing of all the sprayer components, circulate clean water through the whole sprayer parts several minutes first with the nozzles off, then flush out the rinsate through the nozzles. Rinsing should be done preferably in the field, or on a concrete chemical mixing/loading pad with a sump to recover rinse water. Regardless, dispose of the rinsate according to what is recommended on the labels of the pesticides you have used. Always check the label for specific instructions. However, most labels recommend following procedure: If rinsing is done on a concrete rinse pad with a sump, put the rinsate collected in the sump back in the tank, dilute it with water and spray it in the field where there is no potential for the rinsate to reach ditches and other water bodies nearby. If the rinsing is done in the field, make sure you are not flushing out the rinsate in the system in one area. It is best to further dilute the rinse water in the tank and, spray it on the field on areas where there is no potential for the rinsate to reach ditches and other water bodies nearby.
Cleaning
Rinsing the system with water as explained above may not be sufficient to get rid of chemicals from the sprayer. This may lead to cross-contamination problems. Residues of some pesticides left in the sprayer may cause serious problems when a spray mixture containing these residual materials is applied on a crop that is highly sensitive to that pesticide. To avoid such problems, it is best to clean and rinse the entire spraying system with some sort of a cleaning solution. Usually, a mixture of 1 to 100 of household ammonia to water should be adequate for cleaning the tank, but you may first need to clean the tank with a mixture containing detergent if tank was not cleaned weeks ago, right after the last spraying job was done. Some chemicals require specific rinsing solution. There is an excellent Extension Publication from University of Missouri which lists many commonly used pesticides and the specific rinsing solutions required for them. It is available online. Check it out (http://extension.missouri.edu/p/G4852). However, you should always check the product label to find out the most recent recommendations on cleaning agents.Cleaning the outside of the sprayer components deserves equal attention. Remove compacted deposits with a bristle brush. Then flush the exterior parts of the equipment with water. A high-pressure washer can be used, if available. Wash the exterior of the equipment either in the field away from ditches and water sources nearby, or a specially constructed concrete rinse pad with a sump. Again, the rinsate should be disposed of according to the label recommendations. As I mentioned earlier, most labels recommend the same practice: put the rinsate collected in the sump back in the tank, dilute it with water and spray it in the field where there is no potential for the rinsate to reach ditches and other water bodies nearby.
Winterizing
Check one more time to make sure there is no liquid left inside any of the sprayer parts to prevent freezing. Especially the pump, the heart of a sprayer, requires special care. You don’t want a pump that is cracked and/or not working at its full capacity because you did not properly winterize it before the temperature falls below freezing. After draining the water, add a small amount of oil, and rotate the pump four or five revolutions by hand to completely coat interior surfaces. Make sure that this oil is not going to damage rubber rollers in a roller pump or rubber parts in a diaphragm pump. Check the operator's manual. If oil is not recommended, pouring one tablespoon of radiator rust inhibitor in the inlet and outlet part of the pump also keeps the pump from corroding. Another alternative is to put automotive antifreeze with rust inhibitor in the pump and other sprayer parts. This also protects against corrosion and prevents freezing in case all the water is not drained. To prevent corrosion, remove nozzle tips and strainers, dry them, and store them in a dry place. Putting them in a can of light oil such as diesel fuel or kerosene is another option.Storage
Find ways to protect your sprayer against the harmful effects of snow, rain, sun, and strong winds. Moisture in the air, whether from snow, rain, or soil, rusts metal parts of unprotected equipment of any kind. This is especially true for a sprayer, because there are all kinds of hoses, rubber gaskets and plastic pieces all around a sprayer. Yes, the sun usually helps reduce moisture in the air, but it also causes damage. Ultraviolet light softens and weakens rubber materials such as hoses and tires and degrades some tank materials. The best protection from the environment is to store sprayers in a dry building. Storing sprayers in a building also gives you a chance to work on them any time during the off-season regardless of weather. If storing in a building is not possible, try covering the sprayer with some material that will protect it from sun, rain and snow. When storing trailer-type sprayers, put blocks under the frame or axle and reduce tire pressure during storage.Finally, check the condition of all sprayer parts one more time before leaving the sprayer behind. Identify the parts that may need to be worked on, or replaced. Check the tank, and hoses to make sure there are no signs of cracks starting to take place. Check the painted parts of the sprayer for scratched spots. Touch up these areas with paint to eliminate corrosion. By the way, don’t forget to cover openings so that birds don’t make a nest somewhere in your sprayer, and insects, dirt, and other foreign material cannot get into the system.
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.
CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information, visit cfaesdiversity.osu.edu. For an accessible format of this publication, visit cfaes.osu.edu/accessibility.