C.O.R.N. Newsletter: 2024-10
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Wheat Management for Spring 2024
Spring is an important time to make key management decisions for winter wheat. Decisions should be made on wheat growth stage, not calendar date or crop height. Correct growth stage identification and knowledge of factors that affect grain yield can enhance management decisions, avoiding damage to the crop and unwarranted or ineffective applications. Several scales can be used to identify wheat growth stages, including the Feekes and Zadoks scale. Here we focus on the Feekes Growth Scale and key spring management practices.
Feekes 5 Growth Stage. At Feekes 5 growth stage, leaf sheaths are strongly erect. This is an ideal growth for spring topdress nitrogen application. Weed control efforts should be made prior to or during Feekes 5.0 with 2,4-D and other labeled herbicides. This is also a good stage to begin scouting for foliar diseases.
Feekes 6 Growth Stage. At Feekes 6 growth stage, the first node is visible above the soil surface and is commonly referred to as ‘jointing.’ Above this node is the head or spike, which is being pushed upwards. To identify Feekes 6 growth stage, you may need to remove the lower leaves and leaf sheath to see or feel the first node (Figure 1). A video demonstrating for identifying Feekes 6 growth stage can be found here: https://www.youtube.com/watch?v=D_f3VrqzV5c&list=PLYlh_BdeqniJ8oD8TnyGhQHRd96ptV0Yt&index=1
Most herbicide applications should be made by the time wheat enters the Feekes 6 growth stage. Herbicide options become increasingly limited as wheat enters Feekes 6 and progresses to the boot stage. Do not apply growth regulator herbicides such as 2,4-D, dicamba, or MCPA after Feekes 6 as these materials can be translocated into the developing head, causing sterility or distortion. Figure 1 in the Weed Control Guide provides growth stage cutoffs for the different herbicide options. Refer to the herbicide label for specific guidelines, as growth stage restrictions vary among different products. Sulfonylurea herbicides are safe at this growth stage, but for practical reasons, weed control should have been completed by now. Wheat can still show good response to nitrogen topdressing at this time.
Figure 1. Wheat stem with leaves and sheath removed showing the first node above the soil surface, indicating Feekes 6 growth stage.
Feekes 7 Growth Stage. At Feekes 7 growth stage, the second node is visible above the soil surface. These nodes are usually seen as clearly swollen areas of a distinctly different (darker) shade of green than the rest of the stem. Wheat will still respond to nitrogen fertilizer applied at Feekes 7 if weather prevented an earlier application; however, mechanical damage may occur from applicator equipment. A video demonstrating for identifying Feekes 7 and 8 growth stages can be found here: https://www.youtube.com/watch?v=bnV57AhUt-Y&list=PLYlh_BdeqniJ8oD8TnyGhQHRd96ptV0Yt&index=2
Figure 2. Feekes 8 growth stage where the flag leaf is visible, but still rolled up.
Feekes 8 Growth Stage. At Feekes 8 growth stage, the flag leaf is visible, but still rolled up (Figure 2). This stage is particularly significant because the flag leaf makes up approximately 75% of the effective leaf area that contributes to grain fill. It is therefore important to protect and maintain this leaf healthy (free of disease and insect damage) before and during grain development. To confirm that the leaf emerging is the flag leaf, split the leaf sheath above the highest node. If the head and no additional leaves are found inside, Feekes 8 growth stage is confirmed. At this stage, the grower should decide whether or not to use foliar fungicides to management early-season and overwintering foliar fungal diseases.
Feekes 9 Growth Stage. At Feekes 9 growth stage, the ligule of the of the flag leaf is visible. After the flag leaf emergence, army worms can seriously damage yield potential. A video demonstrating for identifying Feekes 9 and 10 growth stages can be found here: https://www.youtube.com/watch?v=K1UVNBR2jRk&list=PLYlh_BdeqniJ8oD8TnyGhQHRd96ptV0Yt&index=3
Feekes 10 Growth Stage. At Feekes 10 growth stage (‘boot stage’), the head is fully developed and can be easily seen in the swollen section of the leaf sheath below the flag leaf (Figure 3). This is another important growth stage for making fungicide applications for foliar disease management, particularly late-season diseases such as Stagonospora leaf and glume blotch and rusts.
Figure 3. At Feekes 10 growth stage, the head is fully developed and can be easily seen in the swollen section of the leaf sheath below the flag leaf.
For more information on wheat growth stages and management, please see our FactSheet- https://ohioline.osu.edu/factsheet/agf-126 and Ohio State Agronomy YouTube playlist- https://www.youtube.com/playlist?list=PLYlh_BdeqniJ8oD8TnyGhQHRd96ptV0Yt
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Spring 2024 Weather & Soil Conditions: Update 3
Soil Temperatures and Moisture
Daily average soil temperatures jumped 5-10°F this week due to warmer conditions, randing from the low 50s in Ashtabula to as warm as 57°F at Western in Clark County (Figure 1).
Figure 1: Daily average air temperature (dashed red), two-inch (green) and four-inch (blue) soil temperatures for spring 2024. Soil type and location of measurements (under sod or bare soil) are provided in the lower right corner of each panel. A map of all locations is in the bottom right. Data provided by the College of Food, Agricultural, and Environmental Sciences (CFAES) Agricultural Research Stations located throughout the state.
Another active weather week brought widespread 1.5-3” of rain to the Buckeye State (Figure 2). Some small creeks and streams flooded again, with high flows on all the major rivers. Minor flooding is occurring or expected to occur along most of the Ohio River hampering river barge traffic. Soils are saturate, especially across northern counties (Figure 2). Conditions are likely to remain fairly wet with another week of near to above normal rainfall this week.
Figure 2: (Top) Precipitation (inches) for the 7-day period ending April 15, 2024 courtesy of the Advanced Hydrologic Prediction Service. (Bottom) Calculated soil moisture percentiles as of April 14, 2024 according to the Climate Prediction Center.
For more complete weather records for CFAES research stations, including temperature, precipitation, growing degree days, and other useful weather observations, please visit https://www.oardc.ohio-state.edu/weather1/.
Weather Forecast
We started the week with warm dry conditions for all but far northeastern Ohio, where cooler conditions lingered after some last Sunday night rainfall. A front near the Ohio River will begin to push north on Tuesday bringing a few scattered showers to the region and highs in the 60s and 70s. This front will push north of the state on Wednesday leading to widespread showers and storms, some of which may be severe. A cold front will push through Wednesday night and Thursday, with a secondary cold front bringing a few showers back to the area on Friday. Highs will trend downward into the 50s and 60s on Thursday and Friday. High pressure will slowly take control over the weekend into early next week with even cooler conditions possible. The state should be aware of potential frost and/or freeze conditions for Sunday and Monday mornings. Overall, the Weather Prediction Center is currently forecasting 0.5-1.25” of precipitation over the next 7 days, with isolated heavier amounts (Figure 3).
Figure 3). Precipitation forecast from the Weather Prediction Center for 8pm Monday April 15 – 8pm Monday April 22, 2024.
The 6-10 day outlook from the Climate Prediction Center and the 16-Day Rainfall Outlook from NOAA/NWS/Ohio River Forecast Center show below average temperatures are likely with near average precipitation (Figure 4). Climate averages include a high-temperature range of 61-67°F, a low-temperature range of 39-45°F, and weekly total precipitation of 0.85-1”.
Figure 4) Climate Prediction Center 6-10 Day Outlook valid for April 21 - 25, 2024, for left) temperatures and right) precipitation. Colors represent the probability of below, normal, or above normal conditions.
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Big Swings Ahead for Planting, Growing and Harvest Season
As El Niño continues to weaken in the eastern Pacific Ocean the "rapid change" often leads to a wetting up as we discussed last time for a part of spring. This wetting up has occurred across Ohio in the last month with some areas wetter than others and could continue into May but to a lesser extent. The years where strong El Niño events came to an end in spring include 2016, 1998, 1982, 1973 and 1958. However, as we go into summer and autumn, there is a growing chance of a La Niña returning which is opposite of El Niño. This swing in the ocean pattern will likely put some stress on Ohio crops this year.
Above normal temperatures are expected from May to autumn harvest with the warmth favoring nighttime minimum temperatures more than daytime maximum temperatures. There will likely be some 95+ degree days this summer but there is more of a chance of 75+ overnight temperatures. You can see the official summer temperature outlook by NOAA attached.
Rainfall will see significant swings the rest of this year. We are in a normally wet time of the year currently averaging 0.8-1.0 inch per week. We expect this wetness to last into May. However, as growing season arrives it appears there will be growing variability in the rainfall patterns. In addition, we expect some dryness to expand as summer progresses and La Niña develops with confidence higher for dryness in June and August/September timeframes at this point. The extent of any summer/early autumn drought development needs to be monitored in the coming weeks.
Even though it is typical to still see some light freezes/frosts in April, most data suggests this is not likely as we go into May meaning a near normal last freeze for most of the state.
You can get all the official climate outlooks from NOAA's Climate Prediction Center at https://www.cpc.ncep.noaa.gov .
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Alfalfa Weevil Activity is Beginning to Peak
Alfalfa weevil larval activity is beginning its peak activity in southern Ohio and the rest of the state isn’t far behind. Alfalfa weevil feeding activity is driven by the accumulation of growing degree days (GDD) and reaches their peak feeding and damage when heat units for the area are between 325 and 575 (accumulation from a base of 48°F starting January 1st). The warm temperatures over the past week have contributed to a significant jump in GDD and ramped up alfalfa weevil larval feeding. As of writing this (Jan. 1 – April 14 ), heat units range from 399 in southwest Ohio to 190 in northeast Ohio.
Figure 1. Map of accumulated growing degree days (base 48°F sine calculation method) for January 1 – April 14, 2024 at CFAES Ag Weather stations across the state (https://weather.cfaes.osu.edu//) and additional NOAA stations around Ohio (Midwestern Regional Climate Center (https://www.mrcc.purdue.edu))
Now is a key time to scout fields to be able to control alfalfa weevil in a timely manner. If you are in the northern part of the state, it is still important to scout. Alfalfa weevil is active, despite not yet reaching the 325 heat unit threshold, and if spring continues to be wet, the window to get into the field to control pests may be short. Alfalfa weevil larvae can be identified by their wrinkled green body, black head capsule, and the presence of a white strip that runs lengthwise along their back. They are approximately ¼ inch long or smaller (Figure 2).
Figure 2. Alfalfa leaf with pinhole feeding damage, green alfalfa weevil larvae in different development stages (instars), and brown adults. Photo Credit – Julie Peterson, University of Nebraska
An article was written earlier this year outlining how to scout for alfalfa weevil and can be found here: https://agcrops.osu.edu/newsletter/corn-newsletter/2024-08/scouting-early-alfalfa-weevil-activity. There is also a great video resource outlining the process here: https://forages.osu.edu/video. Once fields are scouted and you have a count of the alfalfa weevil larvae, the following table can be referenced to determine if the pest pressure meets the threshold for control.
Stand Height
(Inches)
Indication of Problem
(% Tip Feeding)
Problem Confirmation
(Larvae per Stem)
Recommended Action
6
25
1
Recheck in a week
9
50
>1
Spray
12
75
>2
Spray
16
100
>4
Harvest early
If alfalfa weevil pressure is high in a stand that is still short a pesticide treatment may be warranted. Consult the OSU and MSU “Field Crops Insect Pest Management Guide” (https://aginsects.osu.edu/extension-publications/msuosu-ipm-guide) and the product label to make the most effective application.
As alfalfa gets closer to the first cutting, higher larvae counts and levels of feeding pressure can be tolerated. If there is alfalfa weevil pressure at first cutting or an early harvest is utilized to limit feeding damage, be sure to scout for larval activity on the regrowth one week after cutting. Heavy infestations of alfalfa weevil can persist past the first cutting and can stunt regrowth, so a second control treatment could be necessary.
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Battle for the Belt: Season 2 Episode 3- April Weather Update
Episode 3 of Battle for the Belt is now available: https://www.youtube.com/watch?v=aXM78qlKrYg
In episode 3, Dr. Aaron Wilson, State Climatologist of Ohio, gives us a spring weather update! Tune in and watch his weather and soil condition updates as we approach planting season. For more details, also check out Dr. Wilson’s article in this issue of the CORN newsletter titled "Spring 2024 Weather & Soil Conditions: Update 3.”
Figure 1. Planting date one soybean plots (planted on March 25) flooded on April 11th at the Western Agriculture Research Station.
What’s Happening in the Field?
Figure 2. March 25th planted soybean on April 8th.
South Charleston received about 2 inches of rain last week (Table 1.), which caused flooding conditions in the soybean plots and soil saturation in the corn plots for planting date 1 (planted on March 25). Because of the warmer weather, growing degree days (GDDs) are accumulating quickly. However, it is important to keep in mind that growth is not only determined by air temperature but also by soil temperature until corn reaches the six-leaf stage. The average 2-inch soil temperature for the week was 56°F, which is satisfactory. Corn begins to emerge at about 100 air-growing degree days, and with warm temperatures that should be achieved this week!
If you would like to learn more about growing degree days and emergence expectations, take a look at this past CORN News Article, “Growing Degree Days vs. Calendar Days – How Long Will Emergence Take?”.
Table 1. Cumulative weekly precipitation, soil temperature, air temperature, and cumulative growing degree day (GDD) data from the Western Agriculture Research Station. Information from CFAES Weather System, https://weather.cfaes.osu.edu/, and CoCoRahs, https://www.cocorahs.org/.
References:
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2024 Second Quarter Fertilizer Prices Across Ohio
Results from a quarterly survey of retail fertilizer prices in the state of Ohio revealed fertilizer prices were slightly lower than national averages reported by Progressive Farmer - DTN (Quinn, 2024). The survey was completed by 32 retailers, representing 19 counties, who do business in the state of Ohio. Respondents were asked to quote spot prices as of the first day of the quarter (April 1st) based on sale type indicated. This is part of a larger study conducted by OSU Extension to better understand local fertilizer prices, which began in December 2023.
In summary, survey participants reported the average price of all fertilizers was lower in Ohio compared to the national prices, except for DAP (18-46-0) at $785/ton in Ohio versus $780/ton nationally, (Quinn, 2024).
The chart below (Table 1.) is the summary of the survey responses. The responses (n) are the number of survey responses for each product. The minimum and maximum values reflect the minimum and maximum values reported in the survey. The average is the simple average of all survey responses for each product rounded to the nearest dollar. We recognize that many factors influence a company’s spot price for fertilizer including but not limited to availability, geography, volume, cost of freight, competition, regulation, etc.
Table 1. Second Quarter 2024 Ohio Fertilizer Prices
Nutrient
Responses (n)
Sale Type
Min
$/ton
Max
$/ton
Avg
$/ton
Anhydrous ammonia 82-0-0
15
FOB Plant
$707
$870
$785
UAN 28-0-0
19
Direct to Farm
$309
$600
$348
Urea 46-0-0
17
FOB Plant
$522
$680
$561
MAP 11-52-0
19
FOB Plant
$745
$1079
$795
DAP18-46-0
9
FOB Plant
$760
$830
$785
APP 10-34-0
20
Direct to Farm
$553
$680
$602
Potash 0-0-60
20
FOB Plant
$432
$512
$472
Ammonium Sulfate 21-0-0-24
18
FOB Plant
$430
$585
$479
Ammonium Thio-Sulfate 12-0-0-26
13
FOB Plant
$325
$448
$385
Poultry Litter
9
Delivered & applied, <25 miles
$45
$72
$55
When compared to results from the previous quarter’s survey, prices for fertilizers saw a modest increase, with only anhydrous ammonia, MAP and potash showing a slight decrease. DAP and urea saw the most increase in price from the previous quarter with DAP up $50/ton and urea up $59/ton. This increase equates to an increase in price of 9% for both DAP and urea. Only ammonium thio-sulfate remained unchanged.
Quarter 2 survey data included nine responses to questions about poultry litter, delivered and applied within a 25-mile radius of the facility. Prices ranged from $45-72/ton with an average of $55/ton reported. If you are a retailer interested in participating in this study, please contact Amanda Bennett at bennett.709@osu.edu.
Resources
Bennett, A., Richer, E., & Schroeder, C. (2024). 2024 First Quarter Fertilizer Prices Across Ohio. Ohio Ag Manager Blog.
https://u.osu.edu/ohioagmanager/2024/01/17/first-quarter-2024-fertilizer...
Quinn, R. 2024. DTN Retail Fertilizer Trends. DTN Progressive Farmer. Accessed online April 11, 2024 at https://www.dtnpf.com/agriculture/web/ag/crops/article/2024/04/10/uan28-leads-fertilizer-prices-higher
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FRST Fertilizer Recommendation Support Tool Launches Nationwide to Digitize Crop Nutrient Management
The FRST project partners are proud to announce the nationwide release of the FRST (Fertilizer Recommendation Support Tool), a decision-aid that provides an unbiased, science-based interpretation of soil test phosphorus and potassium values for crop fertilization.
The FRST project is a collaboration of over 100 soil science and agronomic professionals representing nearly 50 universities, four divisions of the USDA, several not-for-profit organizations, and one private sector partner. This diverse partnership underscores the collective effort and expertise invested in the development of FRST.
Steve Culman, our former soil fertility specialist, represented The Ohio State University (OSU) and made a significant contribution to the FRST with Ohio based soil data. Currently, OSU is represented on the project by Gregory LaBarge, Leonardo Deiss, Jim Ippolito and Manbir Rakkar.
Gregory and Leonardo noted that, “we are extremely excited about the launch of the decision support tool. FRST was developed in response to the pressing need to harmonize soil testing across state boundaries. It represents an improvement in our ability to evaluate soil test correlation.”
The new web-based tool represents a significant advancement in soil testing for phosphorus and potassium and nutrient management that uses data from across the U.S. with the hope of potentially saving farmers millions of dollars annually while reducing excess nutrient losses to the environment.
Deanna Osmond, soil science researcher at NC State University, is one of the group’s leaders.
“Until now, soil fertility faculty in each state worked independently,” Osmond said. “But for farmers who work across state lines, it’s difficult to compare or assimilate multi-state guidelines. Our goal is to improve the accuracy of nutrient recommendations through independent, scientifically-developed nutrient management best practices that farmers can believe in and adopt.”
Currently, the FRST provides critical phosphorus and potassium soil test values. Critical soil test values indicate where there is no expected yield increase from phosphorus or potassium fertilizer application. In the next phase, the FRST will provide research-based phosphorus or potassium rate response information to assist farmers in selecting the minimum fertilizer rate expected to produce maximal crop yield.
The current version (FRST v1.0) includes data from nearly 2,500 phosphorus and potassium trials for 21 major agricultural crops, with the majority as corn and soybean.
The FRST includes a map of the US that shows the location of phosphorus and potassium trials represented in the database and can be used to identify where the need for additional research data is greatest.
The database was constructed from both historical and current research data and includes trials from 40 states and Puerto Rico. The team has plans to expand to other crops, cropping systems, and other nutrients, such as sulfur.
Key Features of FRST Include:
- Data-Driven: FRST utilizes a dynamic database of soil test correlation data that is constantly updated to improve testing confidence.
- Crop Specific: The database currently covers 21 major commodity crops.
- Geographically Diverse: Includes published and unpublished trial data from 40 states and Puerto Rico.
- Unbiased: Blended data removes political and institutional bias in soil test interpretation.
- Scientifically Sound: Data represents a minimum dataset that provides reliable outcomes.
Nathan Slaton, soil science researcher at University of Arkansas and a leader on the project, noted that “The FRST project has accomplished two really important objectives to advance phosphorus and potassium management for crop production. The first was developing a national database to archive soil test correlation and calibration research ensuring that research information that supports crop fertilization recommendations is not lost as scientists retire. The second is providing a tool that anyone can use to review the research results relevant to their crop, soils, and geographic area to check their soil-test-based fertilizer recommendations. “
Hosted in a neutral space with common access, FRST fosters collaboration and innovation in soil fertility research, paving the way for future advancements in nutrient management.
Greg Buol of NC State University who has provided database and programming support stated, “the design of FRST has always been focused on the end user being able to easily use the tool and understand the results.”
"We believe that FRST will not only benefit farmers by improving farm economics and conservation practices but also contribute to global sustainability," concluded Ippolito and Rakkar
For more information about FRST and how it can transform nutrient management on your farm or in your organization, visit https://soiltestfrst.org"https://soiltestfrst.org and click on “Tool”.
Funding for the FRST project has been provided by the USDA-NRCS including the Conservation Innovation Grants, USDA-ARS, and USDA-NIFA, and OCP North America.
Contact:
Manbir Rakkar
Assistant Professor of Soil fertility
The Ohio State University
OR
Deanna Osmond, Professor of Soil Science, NC State University
OR
Nathan Slaton, Assistant Director of the Arkansas Agricultural Experiment Station, University of Arkansas Division of Agriculture
Authors: FRST collaborators
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 an accessible format of this publication, visit cfaes.osu.edu/accessibility.