C.O.R.N. Newsletter : 2015-31

  1. Farm Science Review 2015--Last Minute Reminders

    Harvest has started in many areas of Ohio. At the Farm Science Review we have some of the crop off to allow demonstrations to begin. Yields are in the 180 range for corn and 50’s for soybean. Field demonstrations will include soybean and corn harvest, of course; plus drones/UAVs, soil sampling, planters, precision nutrient placement and drainage installation.

    Visit the Agronomic Crops Team. We will again be the welcoming crew as you enter the grounds from the public parking lot on the east side of the exhibit area. We can talk about weeds, insects or disease; continue on with a discussion about corn and soybean production practices and more. This year we have also in place long-term demonstrations on soil quality along with several cover crops. Stop off in the Agronomy Plots as you arrive or on the way out.

    The Farm Science Review app, which can be used on both Apple and Android smartphones and tablets, can be downloaded in the Apple App Store or the Google Play Store by searching for “FSR 2015,” or by directing your mobile browser tohttp://fsr.osu.edu and clicking on the visitor tab.

    With the app, users can:

    * View the complete show schedule and create a personal schedule.

    * View detailed session information, including speaker bios.

    * Provide feedback on sessions.

    * View a show map.

    * Locate food vendors.

    * View exhibitor information.

    * Connect with Farm Science Review on Facebook and Twitter.

    CCAs can also get continuing education credits at the Gwynne Conservation area, the Small Farm Center and with us in the Agronomy Plots, watch for the FSR CCA College signs. For a complete FSR CCA CEU schedule:https://agcrops.osu.edu/links/2015_CEUs_at_FSR.pdf/view.

  2. Fall Herbicide Applications and New Technology

    Author(s): Mark Loux

    The C.O.R.N. archive has a plethora of previous articles about fall herbicide treatments, including the importance of these for management of marestail.  Nothing has really changed that would merit rehashing all of this again – don’t spend a lot of money, save the residual herbicide for spring, etc.  However, some discussion relative to the Enlist and Xtend technology might be useful, especially for anyone who has already decided that fall treatments will no longer necessary based on the coming ability to use 2,4-D or dicamba in spring burndown and postemergence treatments.  This is some truth to this with regard to marestail control at least, but before you wash your hands of fall treatments consider the following:

    - fall herbicide treatments initially caught on to remedy the problem of having a lot of weed cover in no-till fields in spring, which caused problems with tillage and planting and harbored insects and soybean cyst nematode.  Not every no-till field needs fall treatment but it’s really handy for the ones that do have a lot of winter weeds.  Spring burndown treatments often don’t control and dry down weeds fast enough to solve this problem.

    - fall is still the key time to control tough biennials and cool-season perennials – wild carrot, poison hemlock, dandelion, etc.  Spring/summer treatments of 2,4-D or dicamba won’t necessarily be as effective.

    - A spring application of dicamba/glyphosate often adequately controls marestail, even in the absence of treatment the previous fall.  However, variability of marestail control with spring-applied 2,4-D/glyphosate has been a major problem in the state, primarily in fields not treated the previous fall or those not treated until sometime in May.  A POST application of Enlist Duo tends to finish off the marestail that survive an application of 2,4-D/glyphosate earlier in spring.  However, the need to make two applications of Enlist Duo to control plants that were there at the time of the first application is fairly guaranteed to result in the development of 2,4-D resistance (the “resistance is us” program).  Keeping fall herbicide treatments in the program should go a long way toward avoiding this problem, although not if 2,4-D is the primary herbicide controlling marestail in fall also.

    And this leads to the following caution:

    - we have been using a lot of 2,4-D in fall and spring burndown treatments, and now we will have the option to use even more with POST treatments to Enlist soybeans.  The same can be said for dicamba – it has been used in fall treatments (usually with 2,4-D) and now we can make multiple applications from fall through summer.  Overuse of these herbicides for control of marestail will certainly induce selection for resistance, and its also possible that there are already populations of marestail with reduced response to 2,4-D.  Preventing this from occurring will require: 1) keeping residual herbicides in the spring applications, which can reduce the need for POST application of 2,4-D or dicamba; and 2) including some other herbicides with foliar activity on marestail to mix with or replace 2,4-D/dicamba in certain applications .  Examples:  including Sharpen in the spring burndown; replacing glyphosate with glufosinate in POST applications to Enlist soybeans.  The goal here will be to mix it up where it makes sense to do so, without making programs more expensive.

  3. Soil Sampling in the Spring vs. Fall

    Anthony Fulford was also a contributor on this article.

    Soil sampling for lab analysis is a critical aspect of effective nutrient management, as it provides valuable information on the fertility status of your soil. Many producers find that fall is an ideal time to sample soil for several reasons: 1) soils often have an ideal moisture range that makes sampling easy, 2) it gives producers ample time to apply fertilizer or lime before the next crop and 3) it helps ensure spring planting will not be delayed.

    Of course, soils can be sampled at other times of the season, most commonly in the spring before planting. But how will soil sampling at different times of the year affect your soil test results? A study from the University of Kentucky found that soil values will vary seasonally, and that they tended to be lowest in the fall. To see how this compared with Ohio soils, we conducted a small study to compare differences in spring vs. fall sampled soil.

    We sampled soils last fall and this spring from a long-term fertilizer trial at three OSU research farms in Clark, Wayne and Wood Counties. We sampled soils from 0-8 inches from 36 plots at each site. The sites were in corn-soybean rotations and we sampled in the fall after corn harvest and in the spring before soybean planting. No amendments or fertilizers were added in between samplings. Clark and Wood Counties were chisel tilled in the fall and Wayne County was chisel tilled in the spring.

    We had a standard soil test run with a Mehlich-3 extraction. To compared the spring vs. fall values, we calculated the relative percentage by:

    (Spring Sampled/ Fall Sampled) x 100.

    Table 1 shows these relative percentage values. Values over 100 indicate greater soil test values in the spring sampled soil, while values less than 100 indicate greater soil test values in the fall sampled soil. Soil pH and cation exchange capacity (CEC) were the only two measurements to show consistent bias across sites. Spring sampled soil had consistently higher pH values and consistently lower CEC values. Organic matter, phosphorus and base cations showed different trends depending on the site.

    Although there was a lack of consistent trends across the sites, within any given site, there were trends of increased values with fall or spring sampled soil. Figure 1 shows spring vs. fall sampled relationships with a 1:1 line. Points falling above this line indicate greater values in the spring and points falling below the line indicate greater values in the fall. These trends underscore the importance of consistently sampling at the same time of the year to get the most meaningful information from your soil tests.

    There are many factors that can influence your soil test results. Time of the year soils were sampled is only one of them. Discussion of other factors can be found here:http://ohioline.osu.edu/agf-fact/pdf/Soil_Sampling_to_Develop_Nutrient_Recommendations_AGF-513-12.pdf


    Managing Seasonal Fluctuations of Soil Tests


  4. Late September Weather

    There has been one change from last week. All indications are the eastern corn and soybean belt will now experience below normal rainfall into mid October. However, the western corn and soybean belt will see normal or wetter than normal conditions.
    Late September into the first half of October will experience above normal temperatures and below normal rainfall.
    RISK into mid October:
    Temperatures - Above Normal (+3-5F) - Normal highs are in the 70s and lows in the 50s.
    Rainfall - Below Near Normal (1.0 inches or less ) - Normal is about 0.5 inches per week. 
    Freeze - Below normal - Little if any expected.
    The NOAA/NWS/Ohio River Forecast Center 16-day rainfall outlook suggests the wet areas will remain west of Ohio. This trend of drier conditions over Ohio will continue into the first half of October.
    October is shaping up to be above normal temperatures and near to drier than normal conditions. Based on historic El Nino events, freeze conditions typically arrive a little later than normal so expect a week maybe two weeks of delay to freeze this fall.
    October is shaping up to be above normal temperatures and near to drier than normal conditions. Based on historic El Nino events, freeze conditions typically arrive a little later than normal so expect a week maybe two weeks of delay to freeze this fall.

    With a significant El Nino expected this fall and winter, everything suggests warmer conditions with below normal precipitation across western Ohio and normal precipitation in eastern Ohio.

  5. Decisions, Decisions, Decisions— Focus on Variety Selection

    Author(s): Anne Dorrance

    Each year things seem to be coming earlier, choices need to be made even before we have this current crop in the grain bin, much less have it sold.  Here are a couple of suggestions as you prepare for the 2016 crop.

    1.       Focus variety selection on the HISTORIC problems for any given field. 

    Diseases do not occur in every field, every year.  Environment plays a very big role in if and when diseases do develop.  Those fields that have a long history of Sclerotinia stem rot, Phytophthora root and stem rot, soybean cyst nematode, brown stem rot, and sudden death syndrome.  The inoculum may decline a bit, but it is always there, in wait for the highly susceptible variety and the perfect environment to strike again.  As you meet with your seed rep this week at Farm Science Review or in the coming weeks – focus on the varieties that have the best disease resistance package for your farm or particular field.  It really is important.  This will save you money in lost yield but also in the added costs of going in with fungicide applications later to try and save the yield you hope to get.

    2.       Don’t plant the same variety in the same field again next year – ESPECIALLY if you had disease this year.

    We’ve learned this one the hard way a couple of times in the past.  If you have had a disease outbreak of frogeye leaf spot, heavily stunted plants due to very high soybean cyst nematode populations – the best thing to do is to rotate out of soybeans.  Wheat and corn make great rotation crops for these situations, especially if your SCN populations are so high that they are reducing plant height (and yield)!  For frogeye leaf spot, this pathogen (Cercospora sojina) does overwinter here in Ohio.  If you levels of frogeye hit the 6% leaf area affected or higher in the top canopy – it is time to switch to a different variety, move the resistance to frogeye as the main selection factor for variety selection for 2016.

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.


Andy Michel (State Specialist, Entomology)
Dennis Riethman (Educator, Agriculture and Natural Resources)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
Les Ober, CCA (Educator, Agriculture and Natural Resources)
Mark Badertscher (Educator, Agriculture and Natural Resources)
Peter Thomison (State Specialist, Corn Production)
Pierce Paul (State Specialist, Corn and Wheat Diseases)
Sam Custer (Educator, Agriculture and Natural Resources)
Sarah Noggle (Educator, Agriculture and Natural Resources)


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.