You are here
Corn Newsletter : 2019-07
Assessing Winter Damage and Evaluating Alfalfa Stand Health
The winter of 2019 has seen a lot of variability including large temperature swings, snow cover, no snow cover, rain, sleet and ice. One constant for most areas of the state is that soils have remained wet and/or saturated throughout the fall and winter period. Add all of this together and there is the potential for some significant winter injury. Forage growers should plan to spend time assessing winter damage and evaluating the health of their forage stands, particularly alfalfa stands. Assessment and stand health evaluation can begin once plants start to green up and produce 2 to 4 inches of growth.
One of the primary concerns is the possibility of heaving damage. Tap rooted crops such as alfalfa and red clover are particularly susceptible to heaving damage. Conditions that increase the likelihood of heaving are wet, saturated clay soils with high shrink/swell potential, exposed to rapid freeze/thaw cycles. During these conditions plants can be physically lifted (heaved) out of the soil exposing the crown of the plant to possible low temperature damage and/or physical injury from harvest operations. In severe cases the plant can be heaved several inches or more out of the soil, breaking the taproot and killing the plant.
Forage stand health evaluation includes stem counts and digging plant roots. Select random sites throughout the field and evaluate the plants in a one-foot square area. Check at least one site for every 5-10 acres. Increasing the number of random samples provides a more accurate assessment. Begin your stand health evaluation by counting the number of stems per crown. Do this evaluation in at least 4-5 random locations for every 20-25 acres. Stem density counts provide an indication of the yield potential of the stand. The following table is taken from University of Wisconsin Extension publication A 3620; “Alfalfa Stand Assessment: Is this stand good enough to keep?”
Stem number/square foot
Expected result or action
Stem density not limiting yield
Some yield reduction expected
Less than 39
Consider stand replacement
While you are counting stems, take note of where growth is taking place. Healthy plants have symmetrical, even growth on both sides of the crown. Damaged plants often have more stems on one side of the plant than the other.
While plant and stem counts are useful, to get a true determination of stand health, crown and root tissue should be evaluated to provide an indication of how the plant will hold up to stresses in the coming growing season. This involves digging up plants and splitting the crowns/roots. Dig up five to six plants in those 4 to 5 random locations per 20-25 acres. Split the plant open. A healthy root will have a creamy white color and no to very little discoloration in the crown and taproot. These are the plants that have numerous shoots and the shoots are evenly distributed across the crown of the plant.
Discolored crowns and roots indicate a plant health problem. They are a darker white, tending towards a tan color. There may be obvious areas of root rot and crown rot that are dark brown to black in color. There may be streaks of brown running down the root. These plants typically have fewer stems coming out of the crown and those stems may tend to be more numerous on one side of the crown as compared to the other. Generally, these plants green up in the spring of the year and appear productive, but because of their compromised root system, they may not survive the entire production year, especially if we have a hot, dry year.
In general, if more than 30% of the split roots have brown streaks running down the root and/or black areas of root/crown rot that cover greater than 30 to 50% of the roots diameter, then yield potential is significantly reduced. The grower may want to consider alternative production options such as terminating the stand after first cutting and planting to corn for silage or possibly to a warm season annual forage crop such as sudangrass or a sorghum x sudangrass. The previously mentioned University of Wisconsin publication has a root health rating system along with color photo illustrations that can be used to make a root health assessment (https://fyi.extension.wisc.edu/forage/alfalfa-stand-assessment-is-this-stand-good-enough-to-keep/).
Taking the time to assess the extent of winter injury to forage and to do a stand health evaluation will allow the grower to determine the yield potential of the stand and whether or not the stand needs to be replaced at some point this year.
New Requirements to Apply Dicamba!Author(s): Jennifer Andon
As of October of 2018, the EPA announced that the registration for dicamba will be extended for two years for over-the top use of dicamba resistant corn and soybeans. Additionally, new regulations now require that to mix, load or apply dicamba, you must be a licensed pesticide applicator. The trained serviceperson is no longer qualified under the new regulations. To receive a pesticide license to mix, load or apply dicamba, one must pass both the Core and Category 1 (Grain and Cereal Crops) exams offered by the Ohio Department of Agriculture. The Ohio State University Pesticide Safety Education Program has prepared training videos to assist growers in preparing for the Core exam. These trainings are supplemental to the study manuals and will not include the annual dicamba training, which is also mandatory. For more information regarding the New Pesticide Applicator Training courses and videos, and online dicamba training, please go to: https://pested.osu.edu/PrivNewApp
The Haney Test for Soil HealthAuthor(s): Alan Sundermeier, CCA
The Haney test was developed by Rick Haney of United States Department of Agriculture-Ag Research Service in Temple, Texas.
The Haney test uses unique soil extracts in the lab to determine what quantity of soil nutrients are available to soil microbes. This test also evaluates soil health indicators such as soil respiration (Solvita CO2 burst test) , water-soluble organic carbon and organic nitrogen and their ratio. These results indicate the amount of food that is readily available to soil microbes and is sensitive to measuring root exudates and decomposed organic material. These numbers should be used as a comparison over time to determine progress in improving soil health.
Other test results included in the Haney test are: nitrate, ammonia, phosphate, aluminum, iron, phosphorus, calcium, magnesium, and sodium.
A soil health score is calculated based on soil respiration and water extractable carbon and nitrogen. This score can be used to compare that specific soil location over time or compare between different site management practices. The goal is to improve the soil health score by utilizing soil building practices such as no-till and cover crops.
Calibration of test results is needed since the Haney test uses different extracts compared to traditional soil test labs. The numbers generated on the soil health report need to relate to how much of the fertilizer nutrient is needed to achieve potential crop yield.
Caution should be used when following the nutrient quantity available for the next crop recommendations. Use small test strips to compare the Haney nutrient rate to your normal fertilizer rate before committing large acreages.
The value of the Haney test is to determine a baseline of soil health for that location. It is important to standardize the time of year and crop rotation when comparing over time.
More information is available at:
Ward laboratory https://www.wardlab.com/
Brookside Laboratory https://www.blinc.com/
Midwest Laboratory https://midwestlabs.com/
Honey Bee Health around Grain Crops
The National Corn Growers Association in partnership with the Honey Bee Health Coalition recently published Corn Best Management Practices for honey bee health. The team who developed the BMPs was comprised of growers as well as beekeepers and businesses that deal with these crops. In 2018, BMPs for soybean growers were developed, also.
BMPs for corn: https://honeybeehealthcoalition.org/cornbmps/
For soybeans: https://honeybeehealthcoalition.org/soybmps/
The link to the HBHC is https://honeybeehealthcoalition.org/ for more information about bees and beekeeping practices.
Locally you can see information about honey bees:
- On the Ohio Department of Agriculture Apiary website: https://agri.ohio.gov/wps/portal/gov/oda/divisions/plant-health/apiary-program/
- and from OSU’s Bee Lab: https://u.osu.edu/beelab/
Concerned about sensitive crops and honey bees?
The Ohio Sensitive Crop Registry (OSCR) brought to you by FieldWatch (www.fieldwatch.com) allows beekeepers and commercial producers of specialty crops (such as tomatoes, fruit trees, grapes and organic crops) to register and map their sites online with an easy-to-use mapping tool and provide contact information about their operation.
- Pesticide applicators can access the site to help determine the scope and location of specialty crops and beehives in their areas. Registered applicators can sign up to receive email notifications when new specialty crop fields or beehives are added to their designated state, county or areas.
- Pesticide applicators will have different options for viewing locations on the new system but all users (applicators, producers, and beekeepers) will need to go to www.fieldwatch.com and create an account to get started.
- Apiary registration with ODA is mandatory in Ohio, and you need a registration number from ODA in order for a beekeeper to set up an account in FieldWatch.
Keep an Eye Out for Water Quality Risk This SpringAuthor(s): Greg LaBarge, CPAg/CCA
Research measuring nutrient losses from surface and subsurface drainage in Ohio indicates that not all fields contribute equally to various water quality issues. Fields with higher than average potential losses have some characteristics observed during everyday field activities or when working with agronomic records. For example, a stream bank collapsing and sloughing off is adding to downstream sedimentation issues, or a field with a soil test report showing phosphorus levels above agronomic need can result in higher soluble phosphorous losses. Having landowners and operators recognize these higher risk scenarios and react to them by contacting conservation professionals can help speed water quality improvements.
Developing private-public partnerships in which the landowner and farmer are active participants in identifying critical concerns and bringing them to the attention of conservation professionals is a key recommendation in a new Bulletin 969- A Field Guide to Identifying Critical Resource Concerns and Best Management Practices for Implementation and accompanying website https://agbmps.osu.edu/. The guide was prepared with cooperating agencies and organization through a grant from the Ohio Soybean Council.
The bulletin focuses on erosion, phosphorus and nitrogen. It describes scenarios and provides pictures in which losses of soil, nitrogen and phosphorus resulted in higher quantities or concentrations in studies measuring water leaving at the field edge conducted in Ohio. The bulletin then provides a list of common Best Management Practices (BMP’s) for the different critical concerns. Along with listing best management practices, the bulletin provides the cost, advantages and precautions to consider helping narrow down the best practice to use.
The guide includes practices used on a field, at the edge of a field and within a stream. In-field practices occur in the boundaries of the field such as tillage, cover crops and nutrient applications. Edge of field practices modify water leaving the field with practices such as drainage water management, or filters. In-stream practices modify the stream or filter water moving down the ditch or stream. Practices addressed include erosion control, water control, filters and 4-R nutrient stewardship – proper place, time, rate and source.
The upcoming spring season provides a new opportunity to inventory potential high-risk concerns.
For soil erosion, look for both stream/ditch bank and gullies in the field. Unstable stream banks can continually collapse moving large amounts of soil downstream. Where gullies form annually in a field, use best management practices, such as changing tillage, use cover crops or permanent grassed waterways to slow water movement to reduce soil loss. Studies measure greater nutrient concentrations in water that leaves the field after moving across the soil surface. Rather than direct surface water to a pipe located in the field and out through the tile system as surface water install a blind inlet? A blind inlet is a BMP where water leaving the site infiltrates the soil before leaving via a subsurface perforated pipe system.
Nitrogen losses tend to be higher when using manure and fertilizer in combination for corn or wheat production. Using tests to estimate nitrogen available from manure before applying additional commercial nitrogen can be positive from an economic and environmental standpoint. Changing manure application timing from a fall application to a spring application when the crop is growing will better utilize manure N, replacing purchased nitrogen. Nitrogen losses to waterways occur through field tile during the non-growing season are reduced by using cover crops or water management.
A soil test can indicate the potential for losses in phosphorous. The type of soil, as well as the timing and fertilizer application method, affect the extent of phosphorous losses. A phosphorous index tool can be used to estimate losses and identify the cost and effectiveness of water management BMP’s. Subsurface placement of fertilizer or manure is a good option to reduce risk of loss at nutrient application.
Bulletin 969 is available to people operating in the Western Lake Erie Basin at Soil and Water Conservation Offices serving that region through a grant from the Ohio Soybean Council. Ohio State University Extension Offices in that region have limited copies. Statewide, the printed guide can be purchased for $10 or as a downloadable pdf file $8.50 from https://extensionpubs.osu.edu/. Content is also available at the website https://agbmps.osu.edu/.
Estimating Wheat Yield With Stem CountsAuthor(s): Laura Lindsey
Between planting in the fall and Feekes 4 growth stage (beginning of erect growth) in the spring, winter wheat is vulnerable to environmental stress such as freezing temperatures with limited snow cover, saturated soils, and freeze-thaw cycles that cause soil heaving. All of which may lead to substantial stand reduction.
However, a stand that looks thin in the spring does not always correspond to lower grain yield. Rather than relying on a visual stand assessment, farmers should estimate the yield potential of their winter wheat crop by counting stems, before deciding whether a field should be destroyed. An alternative method to evaluate wheat stand is fractional green canopy cover (FGCC). Fractional green canopy cover can be used to measure the canopy surface area using the mobile device application Canopeo. The app can be downloaded for free here: http://www.canopeoapp.com.
Wheat Stem Count Methods: Wheat stems (main stem plus tillers) should be counted at Feekes 5 growth stage (leaf sheaths strongly erect) from one linear foot of row from several areas within a field (Figure 1).
Figure 1. Measurement tool used to consistently count the number of stems in one foot of row.
Fractional Green Canopy Cover Methods: Fractional green canopy cover should be measured at Feekes 5 growth stage using the mobile device application, Canopeo (http://www.canopeoapp.com). The camera should be held at a height to capture three rows of wheat in the image (Figure 2).
Figure 2. Winter malting barley image analyzed for fractional green canopy cover with the Canopeo mobile device application.
After counting the number of wheat stems or measuring FGCC, Table 1 can be used to estimate wheat grain yield. For example, if an average of 51 stems is counted from one foot length of row, the predicted grain yield would be 100 bu/acre. Similarly, if the average FGCC measurement was 35%, the predicted grain yield would be 100 bu/acre.
Table 1. Estimated grain yield based on number of stems and fractional green canopy cover (FGCC).
(# per foot of row)
Tri-State Farm Bill SummitAuthor(s): Sam Custer
The 2018 Farm Bill, passed by Congress and signed by President Trump, now awaits implementation by United States Department of Agriculture (USDA), agencies like the Farm Service Agency, Natural Resources Conservation Services, Risk Management Agency and many others. The passage of the farm bill authorizes funding for many of the federal programs producers utilize throughout the growing season. This bill is considered to be mostly evolutionary not revolutionary, but there are still changes that will be important to producers and agribusinesses.
The Ohio State University, the Purdue Center for Commercial Agriculture, the University of Kentucky and Farm Credit Mid-America are jointly sponsoring a Farm Bill Summit on Thursday, April 11, 2019 at the Versailles High School in Versailles, Ohio. The program will feature presentations by three of the nation’s top ag policy professionals: Keith Coble from Mississippi State; Jonathan Coppess from the University of Illinois; and Patrick Westhoff from the University of Missouri’s Food and Agricultural Policy Research Institute. The three keynote speakers will speak on their areas of expertise and cover the three largest agricultural titles in terms of spending within the farm bill: commodities (Patrick Westhoff), conservation (Jonathan Coppess) and crop insurance (Keith Coble).
Free registration is available here. Refreshments will be served at 6:00 p.m. with the program starting at 6:30 p.m.
Weather Outlook PodcastAuthor(s): Amanda Douridas
Listen in on Wednesday to the new Agronomy and Farm Management Podcast episode featuring Aaron Wilson, researcher with the Byrd Polar and Climate Research Center and OSU Extension. Wilson covers weather conditions as we head into planting and an outlook for the growing season. We also talk about changing weather patterns and what that means for agriculture in Ohio.
You can listen and subscribe to the podcast on Stitcher (go.osu.edu/StitcherAFM) or iTunes (go.osu.edu/iTunesAFM). Follow us on Twitter and Facebook (@AFMPodcast).
Fertilizer Certification for New ApplicatorsAuthor(s): Chris Zoller
Are you certified to apply fertilizer? If you apply fertilizer (other than manure) to more than 50 acres of land to crops grown primarily for sale, you need to hold a fertilizer certificate from the Ohio Department of Agriculture. The Tuscarawas County office of Ohio State University Extension will conduct a fertilizer certification training for anyone needing to obtain a certificate. This is NOT recertification. The training will be held April 9 at 7pm at the Community Center in the Village of Tuscarawas at 222 E. Cherry St.
To register, please contact the Tuscarawas County office of Ohio State University Extension at 330-339-2337 no later than April 5. Additional information is available at http://tuscarawas.osu.edu.
About the C.O.R.N. Newsletter
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.
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.