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C.O.R.N. Newsletter: 2015-16

  1. June Weather

    Rain in the extended forecast
    Author(s):

    There is not much change from the last article. It appears June will remain a warm and humid month overall. Most daytime temperatures will remain at or below 90 degrees but nighttime low temperatures will be much above average due to more clouds and humidity during June. Expect lots of lows in the 60s and even some 70s in June.

    Even though there are pockets of dry areas, expect a wetter month of June. There are some scattered rain chances early and again the middle of the week but it will be scattered. Rain chances appear to increase into the week of June 14-21 with locally heavy rain possible.

    See the latest week 2 outlook from NOAA at:

    http://www.cpc.noaa.gov/products/predictions/814day/814prcp.new.gif

    http://www.cpc.noaa.gov/products/predictions/814day/814temp.new.gif

    The 16-day rainfall outlook on NOAA/NWS/Ohio River Forecast Center:

    http://www.erh.noaa.gov/ohrfc/HAS/images/NAEFS16day.pdf

    Normal rainfall is close to an inch per week.

    The latest water resources outlook from the Ohio River Forecast Center can be found at:

    http://www.erh.noaa.gov/ohrfc/WRO.shtml

    Looking ahead into July, temperatures still look normal or slightly above normal with rainfall possibly drying out.

  2. OSU Weed Science Field Day

    Author(s): Mark Loux

    The 2015 OSU Weed Science Field Day will be held on Wednesday July 8 at the OARDC Western Ag Research Station.  Registration starts at 8:30 and a field tour with presentations by OSU faculty, staff and students will start at 9 am.  There is also, as usual, the opportunity to view studies of interest on your own.

    The cost is $30, which includes the tour book and lunch.  Please RSVP to Bruce Ackley, Ackley.19@osu.edu, and include the number of people in your group.  Payment can be via cash or check the day of the event.  Address of the research station – 7721 South Charleston Pike, South Charleston, OH.  Location – about 5 miles south of I-70 on SR 41.

  3. Look Out for Potato Leafhoppers in Alfalfa

    Author(s): Andy Michel

    Now that most alfalfa has had its first cutting, it is time to begin sampling for potato leafhoppers as the crop reaches a sufficient height for sweep-net sampling.  A single sample is 10 sweeps of a sweep net. 

    When the average number of adults and nymphs in a sample is equal to or greater than the average height of the alfalfa stand, insecticide treatment is warranted.  For example, if the alfalfa is 6 inches tall and the average number of leafhoppers is 6 or higher, you should consider an insecticide application. If the average is lower, then re-sample the field in a few days.

    There are alfalfa varieties that are resistant to the leafhopper, these have glandular hairs which help limit feeding.  If you are growing resistant alfalfa, the above threshold should be increased 3-times (for example 18 leafhoppers for 6 inch tall alfalfa).  However, if the resistant alfalfa is a new planting this spring, growers might want to use thresholds meant for regular alfalfa during the very first growth from seeding.  After the first cutting, growers can then use 3X times the normal level threshold.

    More information on potato leafhopper, including how alfalfa growing conditions might affect the threshold, is available at http://ohioline.osu.edu/ent-fact/pdf/ENT_33_14.pdf.

  4. Corn Leaf Striping

    Striped corn present in Wayne Co., 2015. Source: Rory Lewandowski

    I’ve received reports of corn plants exhibiting varying degrees of leaf striping (interveinal chlorosis) across the state.  There are several nutrient deficiencies (including sulfur, zinc, magnesium, and manganese) that result in leaf striping and some of these look similar. The severity of the striping may vary considerably within a field and may be associated with differences in soil pH, organic matter, compaction, tillage, temperature and moisture. Bright yellow to white interveinal striping running the length of leaves may be the result of “genetic stripe”, but it’s usually limited to scattered plants within a field.

    Striping symptoms often disappear when favorable growing conditions promote plant rapid growth after the V8 stage. For more on distinguishing between the different nutrient deficiencies that give rise to striping and the plant tissue sampling procedures for diagnosis, check out articles by Dr. Jim Camberato, Purdue University extension soil fertility specialist,  entitled “Striped Corn - Potential Nutritional Deficiencies” (http://www.agry.purdue.edu/ext/soilfertility/news/Striped_Corn.pdf) and Dr. Chad Lee, University of Kentucky Extension Agronomist, entitled “Cloudy Skies and Striped Corn” (http://graincrops.blogspot.com/2015/06/cloudy-skies-and-striped-corn.html).

  5. Supplemental Forage Options for Early Summer Planting

    Sudangrass
    Author(s): Mark Sulc

    Now that first harvest of forage crops is completed or in progress, some may be noticing the low yields in damaged forage stands, or they may realize the need for additional forage supplies this summer. There is always the temptation to no-till something into existing stands in an effort to produce more tonnage, but I believe that is a risky proposition this time of the year. The existing stand will compete heavily for moisture and regrowth of the existing stand will shade new seedlings struggling to get established. So at this point in the year, I think it is best to either kill a poor stand and seed an annual crop for summer forage production, or find open land available to seed an annual forage for supplemental feed.

    There are several good options for producing supplemental forage from annual crops planted in June, which are discussed here. Additional options for supplemental forage exist for planting in late summer, particularly following wheat harvest. Those options were discussed in an article available at http://corn.osu.edu/newsletters/2012/2012-24/#7.

    Corn Silage. For anyone considering forages for silage, corn should be the first choice because of its high yields and energy content. Corn can be planted as late as mid- to late June for silage production; however, it does carry increased risk especially if dry weather develops. Nevertheless, June planted corn with adequate rainfall can produce more forage with greater feeding value than other summer annual grasses. If forage is needed before the ear is formed, corn can be green chopped. Even without the ear, the feeding value of corn is at least equal to that of the other summer annual grasses and yields are likely to be higher.

    Summer Annual Grasses. Sudangrass, sorghum x sudangrass hybrids, pearl millet, and forage sorghum grow rapidly in summer. When managed properly, these grasses can provide good quality forage. All these species can be planted up to mid-July and will produce 3.5 to 5 tons of dry matter per acre assuming sufficient moisture is present for emergence and growth. Pearl millet is essentially free of prussic acid poisoning potential, while the sorghum species have the potential for prussic acid poisoning which varies by species. Nitrate toxicity is possible with all summer annual grasses. Refer to the Agronomy Guide (pages 111-114) for how to reduce these risks and for more details on establishment and management (https://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins/agron_guide.pdf/view).

    Mixtures of summer-annual grasses and legumes such as field peas and soybeans are marketed by some seed dealers. The legumes generally improve protein content but only in the first growth when they are present. Because the legumes usually increase the seed cost, evaluate the cost to benefit ratio of purchasing mixtures with legumes vs. supplementing livestock with other protein sources.

    Teff is a relatively new warm-season grass option that can be used for hay, silage, or pasture. In our test plots it produced about 3 to 4 tons of dry matter per acre from 3 cuttings (http://oardc.osu.edu/forage2008/table14.asp,http://oardc.osu.edu/forage2009/table11.asp). It can tolerate drought-stressed as well as waterlogged soil conditions. For more details on managing this forage, see an excellent factsheet from Cornell University found athttp://nmsp.cals.cornell.edu/publications/factsheets/factsheet24.pdf.

    Soybean can be grown for forage, but it is extremely difficult to make good soybean hay and ensiling soybean also has problems. The high concentration of fat (about 10%) inhibits bacteria in the silage and fermentation is slow and often incomplete. The best approach to using soybeans as a forage is to mix them with corn plants during silo filling. A mixture of 1 part or more of corn to 1 part soybean works well.  In large diameter upright silos, adequate mixing usually occurs when one load of corn is unloaded followed by one load of soybeans.  In smaller diameter upright silos one-half load of soybeans followed by one-half to a full load of corn will usually result in adequate mixing.  For silo bags, mixing is difficult.  The ratio of corn to soybeans should be increased and the amount of soybeans put in the silo at one time should be small.  The best solution would be to chop about one-fourth to one-half load of soybeans and fill the rest of the wagon with corn. Use of herbicide-treated soybeans for forage or hay is allowed for only a few herbicides, so check chemical labels before using herbicides on soybeans to be used for forage.

    Several brassica species can be planted in May for late summer grazing. For more information on this option, refer to The Ohio Agronomy Guide, pages 114-118.

  6. Still Working on Planting Soybean?

    Author(s): Laura Lindsey

    The majority of the soybean acres in Ohio have been planted.  (According to the USDA National Agricultural Statistics Service, 85% of the soybean acres were planted by May 31.)  However, even if 5% of the soybean acres are not yet planted, with 5.1 million acres of soybean in Ohio, there are still 255,000 acres left to plant.  There are three things to consider when planting soybean in June: 1.) row width, 2.) seeding rate, and 3.) relative maturity.

    Row width.  When planting soybean in June, if possible, row width should be 7.5-inches to maximize light intercepted by the plant.

    Seeding rate.  When planting soybean in the first half of June, a seeding rate of 200,000 to 225,000 seeds per acre is recommended in the Ohio Agronomy Guide.  According to on-farm trials conducted by the Ag Crops Team, 155,000 plants per acreat harvest is needed to maximize yield when planting soybean in June.

    Relative maturity.  When planting late, the rule of thumb is to plant the latest-maturing variety that will reach maturity before the first killing frost.  The table (adapted from the Ohio Agronomy Guide) gives recommended relative maturity based on plant date.  Recommendations are based on years with normal weather and frost dates.  Late-maturing varieties are recommended for late planting to maximize vegetative growth before flowering begins.

    Table 1. Recommended relative maturity ranges for soybean varieties planted in June in northern, central, and southern Ohio (adapted from Ohio Agronomy Guide).

     

    Planting date

    Suitable Relative Maturity

    Northern Ohio

    June 1-15

    3.2-3.8

     

    June 15-30

    3.1-3.5

    Central Ohio

    June 1-15

    3.4-4.0

     

    June 15-30

    3.3-3.7

    Southern Ohio

    June 1-15

    3.6-4.2

     

    June 15-30

    3.5-3.9

     

  7. What’s the Right N Rate for Corn in Ohio?

    The first answer is we don’t know. The truth is that our soils, rainfall, temperatures, the year-to-year variation and cropping systems are different enough that any rate we tell you will be wrong.

    We formerly used crop yield goal to determine our nitrogen (N) rate. Shown here is Table 9 (Nitrogen recommendations for corn based on yield potential and previous crop) from the 1995 Tri-State Fertilizer Recommendations. With a corn yield of 160 bu/A we would recommend 190 pounds of N per acre in a corn after corn situation, and 160 pounds after soybeans. We gave a credit of 30 pounds nitrogen for soybeans.

    Table 9.

     

    Yield potential bu/A

     

    Previous crop

    140

    160

    180+

    Corn

    160

    190

    220

    Soybean

    130

    160

    190

    Those assumptions of the need for about 1 pound of N/bushel of corn and 30 pounds of N credit after soybean were wrong. Today we know that we have a rotation advantage for corn after soybeans – because the soybean residue breaks down more easily than corn fodder. We also from research know that we can grow a good corn crop in Ohio with about 160 lbs N/A, no matter what the yield. In some years and in some situations we can grow that corn crop with no (as in zero) nitrogen and in some situations 240 lbs N/A is not enough. There is little correlation between N applied and crop yield.

    So what is the better answer to arrive at an N rate for corn?

    Today the best suggestion we can make is to use an economic model to determine your most economical nitrogen rate. Ohio has worked with a regional group of universities on a Maximum Return To Nitrogen model (MRTN). The regional calculator is based at Iowa State University, on a website dedicated to this on-line calculator:http://extension.agron.iastate.edu/soilfertility/nrate.aspx.

    To use the MRTN calculator you need 3-4 pieces of information: location, crop rotation, price of N and corn price.

    ·        We choose Ohio as the location, soybean as previous crop, $0.50 for a pound of N and $3.57 as the corn price (today’s local January delivery price).

    ·        The calculator returns an N rate of 158 lbs N/A and that will cost us $79/A.

    ·        And with this N rate, from research conducted in Ohio in on-farm trials, we should achieve 97% of our maximum yield – and delivers the maximum economic yield.

    ·        This is the best suggestion we have for a corn crop in Ohio – use your own nitrogen and corn price for your operation to refine this number.

    Not satisfied with the MRTN, or the no longer useful yield-goal method to determine your corn nitrogen rate? Then explore some of the calculators that are available – Adapt-N, Encirca, Climate Pro, soil nitrate testing, and many more – all have shown some promise. Use of an in-crop sensor is also being looked at in Ohio – again also showing some promise.

    We also want you to consider an N rate trial on your farm, and share the results with us. We shared this trial plan during the winter meetings and encourage wider use.

    ·         N rate treatments:

    o   Treatment #1 = 0 N, as in no nitrogen at all – we allow some flexibility on this one. But you will be surprised at the corn yield.

    o   Trt 2 = 50,

    o   Trt 3 = 100,

    o   Trt 4 = 150,

    o   Trt 5 = 200,

    o   Trt 6 = 250 pounds of nitrogen.

    ·         With 3 replications in a trial plan such as this with randomization:

    Sample Plot Layout

    Rep

    1

     

     

     

     

    Rep

    2

     

     

     

     

    Rep

    3

     

     

     

     

    3

    5

    2

    1

    4

    6

    5

    1

    4

    2

    6

    3

    2

    6

    1

    5

    3

    4

     

    Other information we would request but not required is soil nitrate at V4-V6, an in-crop sensor reading such as from a GreenSeeker, an end-of-season stalk nitrate test and yield. The yield by rate and by replication is the most important information we require. We want to build our database, please help.

    Harold Watters, watters.35@osu.edu, office phone 937 599-4227.

    Steve Culman, culman.2@osu.edu, office phone 330 263-3787.

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

Amanda Bennett (Educator, Agriculture and Natural Resources)
Amanda Douridas, CCA (Educator, Agriculture and Natural Resources)
Ed Lentz, CCA (Educator, Agriculture and Natural Resources)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
John Barker (Educator, Agriculture and Natural Resources)
Les Ober, CCA (Educator, Agriculture and Natural Resources)
Mark Badertscher (Educator, Agriculture and Natural Resources)
Mike Gastier, CCA (Educator, Agriculture and Natural Resources)
Sam Custer (Educator, Agriculture and Natural Resources)
Ted Wiseman (Educator, Agriculture and Natural Resources)

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.

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