C.O.R.N. Newsletter: 2019-21
Drier Week Ahead with Excessive Heat Possible Next WeekAuthor(s): Aaron Wilson
This past week featured a very summer-like pattern, with average temperatures running 2 to 8 degrees Fahrenheit above average and isolated but locally heavy thunderstorm activity. The largest differences compared to average occurred over northwest Ohio, where a lack of crop cover allowed surfaces to dry quickly and temperatures to rise efficiently. Much of the storm activity was found from parts of northwest Ohio, through east-central Ohio, and into the southeast counties, where widespread 2-3 inches fell with local amounts in excess of 5 inches. A CoCoRaHS (cocorahs.org) observer 0.7 miles north of Williamsport in Pickaway County reported 3 separate events over 2 inches this week for a total of 6.70 inches.
The upcoming week features a drier pattern on average across the state, as high pressure settles in over the region early in the week. This initial high will slide to the east on Wednesday and Thursday providing a better chance of isolated storms. High pressure will build back in for the weekend as well. Currently, the Weather Prediction Center depicts much less than 1 inch of rain for the entire state over the next 7 days (Figure 1), with a few localized heavier totals likely to occur with storms, most likely in the east. Temperatures will remain near to above average. Normal highs this time of year are in the mid to upper 80s with lows in the low to mid 60s.
Looking ahead at the 8-14-day outlooks, the NOAA Climate Prediction Center indicates a greater probability of above-average temperatures for the period July 16-22 (Figure 2). In fact, there is a slight (moderate) chance of excessive heat over the entire state (northern Ohio) during this period as well. This heat may challenge poorly established root systems and rapidly increase stress. This is accompanied by a slightly elevated probability of above-average precipitation (Figure 3). Rainfall for this period averages between 0.85 and 1 inch. The 3-4-week outlooks (not shown) generally indicate equal chances of above, below, or near-normal temperatures for all of Ohio, but there are signals indicating an increased probability of drier than average conditions across the northern third of the state. The latest CPC outlooks may be found at https://www.cpc.ncep.noaa.gov/.
Problems in Soybean FieldsAuthor(s): Anne Dorrance
We have multiple planting dates in Ohio this year with soybeans in all different growth stages. Management decisions are based on the stage of crop development.
For soybeans that are flowering, there was a confirmed report of frogeye leaf spot. If the soybeans in the field are in good health then managing this disease is often cost effective on susceptible varieties. Scouting between R2/R3, if frogeye is easy to find on the newly expanded leaves a fungicide application is warranted. There are many fungicides available with fair to very good efficacy. The one caveat is in Ohio, we have identified strains of the fungus that causes frogeye leaf spot that is resistant to strobilurin fungicides, so choose a product that has another mode-of-action.
For soybeans that are in the early seedling stages that have continued to get these saturating rains, damping-off is occurring. So these fields will continue to decline until about V2, then the resistance in the plant will take over. So continue to monitor stands in these fields. If stem rot develops at the later stages, then that is from Phytophthora sojae. In these cases, a better variety is needed for the future that has higher levels of quantitative resistance.
Pictured: Soybean seedling damping off.
Considerations for Using Soybeans as a Cover CropAuthor(s): Laura Lindsey
From the USDA RMA website (https://www.rma.usda.gov/News-Room/Frequently-Asked-Questions/Prevented-Planting-Flooding):
“Q. Can I plant a cover crop of the same crop I was prevented from planting? Or in other words, can I use the seed I have on hand (corn, soybeans, wheat) to plant a cover crop as long as it's at a lower seeded rate that qualifies for cover crop?
A. Yes. An acceptable cover crop must be generally recognized by agricultural experts as agronomically sound for the area for erosion control or other purposes related to conservation or soil improvement is planted at the recommended seeding rate, etc. The cover crop may be the same crop prevented from planting and may still retain eligibility for a prevented planting payment. The cover crop planted cannot be used for harvest as seed or grain.”
Soybean is an acceptable cover crop as it is agronomically sound for the area for erosion control or other purposes related to conservation or soil improvement.
To optimize the use of soybean as a cover crop, consider the following:
- Planting dates. USDA NRCS cover crop practice guidelines state that soybean should be planted between June 15 and August 15 in northern Ohio and June 1 and August 30 in southern Ohio.
- Plant in narrow rows. The USDA NRCS cover crop practice guidelines do not specify a row width for a soybean cover crop, but planting in less than 30-inch rows will maximize ground cover and improve weed suppression. DO NOT BROADCAST TREATED SEED. We want to minimize the risk of seed treatment exposure to non-target organisms.
- Seeding rate. USDA NRCS cover crop guidelines indicate that soybean should be seeded at 54 lb/acre if to be planted as a pure stand (100% soybean) cover crop. At a seed size of 2,800 seeds/lb, this would be a seeding rate of ~151,000 seeds/acre. Higher rates may be used; however, seed treatment labels may limit the amount of active ingredient per acre which can impact upper seeding rate limits.
- Check your license agreement and talk with your seed dealer. Most trait licenses have a clause stating that the crop can be used for “one commercial crop.” You will want to verify with your seed dealer that the cover crop represents a commercial crop prior to planting.
If you are interested in soybean as forage, please see last week’s article here for agronomic practices: https://agcrops.osu.edu/newsletter/corn-newsletter/201919/2019-challenge-forage-production-options-ohio
Kudzu Bug Monitoring SummaryAuthor(s): Amy Raudenbush, Ed Brown, Chris Bruynis, Mary Griffith, Marcus McCartney, Andy Michel, Kelley Tilmon, J.T. Benitez
The kudzu bug, Megacopta cribraria is a serious invasive pest of soybean causing a reduction to yield when heavily infested (Figure 1). In addition to soybean, the kudzu bug also uses the plant kudzu, an invasive weed, as a host. The most recent monitoring efforts indicated that the kudzu bug was not yet reported in Ohio; however, monitoring efforts remain important as the pest expands its host region (Figure 2). Using this information, we worked with Extension Educators in counties where kudzu has previously been reported to monitor for the kudzu bug in Ohio (Figure 2). The monitoring protocol was designed by Virginia Tech and used a PVC pipe and sticky card. Traps were deployed between May through the beginning of June and were monitored weekly until the end of June.
Kudzu bug monitoring in Ohio is now complete with zero kudzu bugs found in Ohio (Figure 3). Overall, 6 PVC traps were monitored in five counties including, Athens, Butler, Madison, Ross and Washington. Although the kudzu bug has yet to be found in Ohio; it is important to continue monitoring efforts to make the best management decisions for our growers. If you suspect kudzu bug in your county please contact your local extension office.
Noxious Weeds in Cover Crop Seed and Seed Germination
Seed quality is key to establishing a good crop (or cover crop). Some of the critical components of seed quality are percent germination, mechanical analysis for purity (% other crops, % inert, and % weeds), and a listing of noxious weeds identified by scientific/common name and quantity found. As producers are looking for seed sources to provide living cover on acreage this year that was previously earmarked for corn or soybeans, it is important to pay attention to the quality. These tests may also be required on seed lots for use in some relief programs as well. Commercial or certified seed used for cover crops should have a seed tag that shows variety and the seed quality measurements above. However, if the seed is sourced from out of state, the noxious weeds listed (or NOT listed) on the tag by name may differ from those had the seed been sourced from Ohio.
Only the noxious weeds for the state where the seed was originally going to be sold are required to be listed on the tag by name and quantity (Federal Seed Act, part 201.16). Each state determines which species are included on this list, and can differ from state to state. If seed is outside of Ohio for use on-farm, producers may want to have the seed tested for an “all state noxious-weed exam” prior to planting if this was not done previously on the seed lot. Only 1.1-1.2 lbs of seed is needed for the test, but it is critical the sample is representative of the lot to ensure quality test results. This test would screen the seed sample supplied for the weed contained in this list: https://www.ams.usda.gov/sites/default/files/media/StateNoxiousWeedsSeedList.pdf, and may serve as a more comprehensive exam than was conducted at the time of initial seed lot labeling. One service provider that can conduct this exam is Central Ohio Seed Testing (a subsidiary of the Ohio Seed Improvement Association; https://ohseed1.org/about-our-lab/). Samples can also be sent to ODA for an Ohio noxious weed exam (https://agri.ohio.gov/wps/portal/gov/oda/divisions/plant-health/grain-warehouse-feed-and-seed/). Depending on the source of seed and the planned use, a seed lot may be eligible to be tested for free through ODA between June and December (up to three per farmer). Conducting a noxious weed exam could help slow the movement of problematic weeds throughout the state and minimize future weed problems.
Another issue to consider is the quality of seed in storage that was not planted this year due to weather. Storing seed in an environment where the temperature (in F) plus the % relative humidity are less than 100 (Harrington’s rule) helps to minimize the rate of seed deterioration (or loss in germination and vigor). Seed germination is an important consideration for determining seeding rate to ensure the critical final stand for yield is achieved for crops like corn and soybeans. Most seed germination percentages on a seed tag for agricultural seeds (like corn and soybeans) are valid for 12 months from the last date of the month in which they were completed, with the exception being cool season grasses which are valid for 15 months beyond the month of testing (Ohio Revised Code, Chapter 907.07). Be sure to check the seed tag for both the date of the test as well as the germination when planning seeding rates.
What is the Nutrient Value of Wheat Straw?
Wheat harvest is now underway. What is the nutrient value of the straw? 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.
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 and/or nitrate form, it is available for plant uptake. The rate of 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.) 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.
Besides providing nutrients, straw has value as organic matter, but it is difficult to determine the dollar value for it. Removal of straw does lower soil potash levels. If straw was removed after heavy rainfall, some of the potash may have leached out of the straw, lowering the nutrient value of the straw. However, a soil test should be done to accurately estimate nutrient availability for future crops.
Hay and Straw Barn Fires a Real Danger
Usually, we think of water and moisture as a way to put a fire out, but the opposite is true with hay and straw, which when too wet can heat and spontaneously combust. Most years this is more common with hay than straw because there is more plant cell respiration in the hay. This year the wheat is at various growth stages and straw seem to have more green stems than normal. When baled at moistures over 20% mesophilic bacteria release heat-causing temperatures to rise between 130⁰F and 140⁰F. These bacteria cause the internal temperature of hay bales to escalate, and can stay warm for up to 40 days depending on the moisture content when baled. If bacteria die and the bales cool, you are in the clear but if thermophilic bacteria take over temperatures can rise to over 175⁰F.
Assessing the Fire risk
- Most hay fires occur within the first six weeks after baling
- Was the field evenly dry or did it have wet spots
- Were moistures levels kept at 20% or less
- If over 20% was hay preservative used
Monitoring at risk Hay
If you are concerned that your hay or straw may be a fire risk because it was baled at a high moisture, you should monitor it twice a day for the first six weeks after baling or until low temperatures stabilize. Ideally, temperatures are taken from the center of the stack or down about 8 feet in large stacks. If you have a long probe thermometer it can be used but some homemade options are available A ¾ inch pipe with the ends closed into a point and 3/16 inch holes drilled in the bottom 4 inches can work well, lower a thermometer on a string or the sensor wire of a thermometer into the pipe. The sensor on a long wire can work very well once in place you can read temperatures without removing it. Leave the thermometer in the stack for 15 minutes to get an accurate reading. Another more crude option is to stick a 3/8 pipe into the stack and pull out twice a day if the pipe is too hot to hold in your hand, you are at risk for a fire. For more information on building your own temperature probe visit https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1115&context=ky_alfalfa. Be very cautious when taking hay temperatures if the hay gets hot and a cavity burns out underneath you can fall in. Use planks to spread out your weight and have someone nearby in case you fall in a burned out pocket or between bales using a harness and tying yourself off would be even better.
Critical Temperatures and Actions to Take
If you are in the risk zone and there is machinery or livestock, also in the barn remove them before removing the hay for safety. Also, call the fire department when you are in the risk range they would much rather be present and not have to put a fire out then have to call mutual aid when your entire barn is on fire. For more information on Preventing Fires in Baled hay and straw visit- http://articles.extension.org/pages/66577/preventing-fires-in-baled-hay-and-straw.
Prevention of Bale fires starts at Baling
- Bale under appropriate conditions to prevent spontaneous combustion. Recommended moisture levels for safe baling of dry hay are as follows:
- Fresh cut hay will usually require several days of curing in the field under Ohio conditions to reach the safe moisture levels prior to baling.
- Using hay tedders, windrow inverters, hay rakes, and conditioning mowers help decrease the moisture content before the hay is baled.
- When baling high moisture hay fields, adjust the volume of the bale to be at a lower density to improve air circulation within the bale.
- Hay preservatives can be applied during baling to high moisture hay. Liquid products like liquid propionic acid inhibit the growth of bacteria. The effectiveness of preservatives is generally good up to 25% moisture, variably effective at 25-30% moisture, and no preservative is very effective above 30% moisture.
For more details on how to maximize field curing for forage harvest, see https://forages.osu.edu/news/how-speed-hay-drying.
- When stacking and storing high moisture hay, allow for more ventilation and air flow around the bales. Good air flow will help the bales return to a normal (ambient) temperature.
- Keep bale stacks low when storing inside a barn.
- Provide wider spacings between stacks when storing outside.
- Keep bales protected from excess ground moisture by storing them on gravel, pallets, used tires or other mechanisms to allow air flow.
Article summary of:
Preventing fires in baled hay and straw. (2012). Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/66577/preventing-fires-in-baled-hay-and-straw.
2019 Agriculture Challenges FAQ Webpage Now LiveAuthor(s): Elizabeth Hawkins
The unrelenting rains this spring and summer have created many challenges that the farming community is now sorting through. In order to help with decisions, OSU Extension has created a Frequently Asked Questions webpage. This page provides the most up-to-date answers to questions about topics ranging from MFP and disaster payments to cover crops, forages, livestock concerns, management of crops that are out of sync with normal planting dates, as well as answers to more questions as information becomes available. There is also an option to submit questions that you would like answered. Webinars with more detailed information will also be shared here. The page is available at go.osu.edu/AgCrisis. Since the situation we are facing is constantly evolving, be sure to check back for the latest information available to help you.
Western Bean Cutworm Numbers Remain Low Across OhioAuthor(s): Amy Raudenbush, Kimberley Gault, Mark Badertscher, Bruce Clevenger, CCA, Sam Custer, Allen Gahler, Jason Hartschuh, CCA, Andrew Holden, Stephanie Karhoff, Ed Lentz, CCA, , , Les Ober, CCA, Eric Richer, CCA, Kaitlin Ruetz, Garth Ruff, Mike Sunderman, Jeff Stachler, , Curtis Young, CCA, Chris Zoller, Andy Michel, Kelley Tilmon
We are in week two of The Ohio State University Western bean cutworm (WBC) monitoring network. Last week’s trap count included WBC adults captured from July 1 – July 6. Overall, 22 counties monitored 64 traps across Ohio. Trap counts increased slightly, resulting in a total of 18 WBC adults (0.3 average moths per trap) (Figure 1). None of the counties reported capturing more than 1 moth / day over the 7 day monitoring period; therefore, all counties currently remain below the recommended levels that indicate scouting for egg masses should begin.
More information on our trapping summary for the 2018 field season can be found here: https://aginsects.osu.edu/sites/aginsects/files/imce/Trapping%20summary%...
Further information on WBC can be found in our fact sheet: http://ohioline.osu.edu/factsheet/ENT-40 and a free article in the Journal of Integrated Pest Management: http://jipm.oxfordjournals.org/content/1/1/A1
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.
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