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Ohio State University Extension

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C.O.R.N. Newsletter 2013-29

Dates Covered: 
September 3, 2013 - September 10, 2013
Editor: 
Adam Shepard

Fall Weather Outlook

Over the last week, rainfall was generally below 0.50 inches with some places in west-central and northwest Ohio near zero. Isolated totals were 0.50 inches to 2 inches, but those were few reports.

The next two weeks will feature slightly above normal temperatures (+1F to +3F) with below normal rainfall. Expect little or no rainfall this week with the next chance for rain Sunday or Monday with another about the middle of next week about September 11. Total rainfall for the first 2 weeks of September will generally be under 0.50 inches.

The outlook for September is slightly above normal temperatures and below normal rainfall.

The pattern may begin to wet up again in October but not until then but it will likely dry out again as we head toward winter.

There are indications that the risk going into 2014 will be on the increase again as rainfall looks to lean toward the drier side but we will refine this in the coming weeks.

Quality Corn Silage Production

Corn silage has the reputation as a reliable and economic feedstuff.  Corn silage is widely used in ruminant livestock rations, particularly with cattle, but I have also seen it used with sheep as well.  A good thought to keep in mind is that the quality of the corn silage you produce this fall will affect your livestock for many months in to the future.  Producing high quality silage depends upon good management practices at several different steps.           

Corn silage is a fermented product.  To be effective that fermentation must take place in an anaerobic (no oxygen) environment.  The goal in this fermentation process is to achieve a pH of less than 4.0.  This can be accomplished when air is removed as quickly as possible after chopping so that high concentrations of organic acids, predominantly lactic acid, are rapidly produced.  This may sound simple, but implementation depends upon good decisions, harvest preparation, and some cooperation from Mother Nature.

The first and most critical step is that corn must be chopped at the right moisture or dry matter (DM) content.  If you don’t get this right, nothing else will matter.  A DM range of 30-38% is acceptable.  Silage put into a bunker silo should be at the lower end of this range while silage put into upright silos should be at the upper end.  Corn less than 27 to 30% DM does not ferment properly.  It produces silage that often has high concentrations of butyric acid and can have a very low pH.  This silage will have an unpleasant odor and animal DM intake will be reduced.  Corn chopped at higher than 40% DM does not pack well.  As a result it usually does not ferment adequately, resulting in low acid concentrations, heat damage and moldy silage.  Starch digestibility is usually low, causing the silage to have less energy.   Silage harvest needs to start on the wetter end of the acceptable range because corn will gain DM content or lose moisture at a rate of between 0.5 to 1.0 percentage points per day.  Rapid harvest is important to ensure that corn is chopped within the acceptable moisture range.          

Chop length is a consideration for silage packing, feeding and animal performance.   A three-eighths inch (3/8) theoretical length of cut (TLC) is recommended for corn at 32 to 36% DM.  When DM is under 32%, a three-quarters (3/4) inch TLC is recommended and when DM content is above 36%, a TLC of less than 3/8 inch is recommended.  There is a reason that this is termed “theoretical”.  The actual cut length in the field can vary so operators should look at the actual chopped forage and make adjustments to get the correct chop length.  One practice that can change these recommendations is kernel processing.  Kernel processing involves fracturing the corn kernels as the corn plant is chopped.   Research results have consistently shown benefits in animal performance when kernels are processed adequately.  The goal is to crack 90 to 95% of the kernels and 70% of those should be fractured to smaller than one-quarter of a kernel.  When kernel processing is a part of the chopping process then TLC is typically increased to three-quarters of an inch.           

One question that often comes up in any silage production discussion is whether or not to use a silage inoculant.  There are 2 main types of inoculants; homofermenters and heterofermenters.  Homofermenters contain Lactobacillus bacteria that produce lactic acid and heterofermenters contain Lactobacillus buchneri that produce lactic and acetic acid.  The lactic acid promoting inoculants are used to increase silage quality by driving the silage pH down quickly and reducing DM loss during the fermentation process.  Dry matter loss during fermentation is higher with the buchneri type inoculants but feed out losses can be reduced.  The buchneri inoculants are used to increase the aerobic stability of silage during feed out.  The acetic acid produced prevents yeast growth.  Bill Weiss, OSU dairy nutritionist located at the OARDC in Wooster says that his standard recommendation regarding inoculant choice is that if you have historically had problems with moldy silage during feed out or if the TMR ration gets hot in the bunk, then use the buchneri type.  If neither of these is an issue, then use the lactic acid promoting type of inoculant.  Regardless of which inoculant type is used, the key is to purchase high quality inoculants and to apply them correctly.

After DM content, the next critical step is the rapid removal of air by packing.  As layers of forage are added to the silo or pile, they need to be driven over multiple times by heavy machinery.  The goal is to achieve a silage density of 15 lbs. of DM/ft3 or higher.  The density is directly correlated with oxygen exclusion within the silage pack and generally high silage density results in lower DM losses.  The guideline for packing is that 800 pounds of packing weight is needed for each ton of silage delivered to the silo or pack.  For example, if the harvest rate is 50 tons/hr. then the packing weight needed is 50 x 800 = 40,000 lbs. or 20 tons.  In addition to the packing weight, the thickness of the layer packed should be monitored.  The optimum condition is to pack layers of 6 inches or less.  Another piece of advice from Bill Weiss regarding packing is: If you think you have packed enough; pack some more.

The final important step is covering the bunker or silage pile.  This should be done as soon as the bunker is filled and the final packing had been done.  Covering prevents oxygen, weather and animals from getting into the silage pack.  Covering reduces DM and spoilage losses.  The recommendation is to cover with plastic of 6 to 8 mil thickness and weigh that plastic down, sealing the edges as well.  University research trials have demonstrated that the oxygen barrier 2-step products have reduced losses more than covering with the 6 to 8 mil plastic.

Updated Fertility Recommendation Spreadsheet

The Fertility Recommendation Spreadsheet has been updated to provide more functionality in developing fertility recommendations based on the tri-state fertilizer recommendation. Feedback from the release last fall was used in updating this version.

New functions include:

·  Phosphorus soil test results from either either Bray P1 or Mehlich III can be entered directly without conversion.

·  Phosphorus and Potassium soil test reported in units of pounds per acre or part per million can be used.

·  A lime recommendation sheet provides lime need adjusted based on ENP of liming source and calculates cost for product and application.

·  A fertilizer recommendation sheet calculates dry fertilizer need and cost on the per acre and total field basis.

·  Crops included include corn, soybeans, wheat (grain only), wheat (grain and straw), corn silage and alfalfa.

The spreadsheet can be found at https://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins or directly downloaded from https://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins/TriStateFertCalcV2013-3.xlsm

2013 Farm Science Review CCA College

The OSU Extension Agronomic Crops Team will again this year offer the FSR CCA College so that those CCAs attending or working at the Farm Science Review can earn continuing education credits. Again this year the FSR CCA College will be all three days of the Farm Science Review. There are several CEU opportunities all over the grounds and all three days – September 17, 18 & 19:

·  At the Gwynne Conservation area will be many Soil & Water CEUs as well as Crop Management talks.

·   We’ll have SW, NM and CM CEUs at the Small Farm Center.

·   New this year - at the Agronomy Demonstration Plots between the east end of the Exhibit Area and the public parking will be scheduled talks from state specialists as well as individual guided tours of the agronomy plots. Talks and hands-on demonstrations will occur each day at 10AM and 2PM, one-half hour each with three talks in the morning and two in the afternoon.

Watch for the “Are You Good Enough to be a CCA?” clipboards posted at each venue. On the clipboard will be sign in sheet; sign in at the time and date of your program and CEUs will be awarded.

·  See all the 2013 FSR CCA College opportunities on the Agronomic Crops Team website under links or: https://agcrops.osu.edu/links/2013-fsr-cca-college. Included will be a listing of approved CEU by venue when received, so check late week or after.

·   Buy Farm Science Review tickets in advance at your local County Extension office and many Ohio agri-busineses for $7 or at the gate for $10. For more information on the Farm Science Review: http://fsr.osu.edu. There is no additional cost for CCA CEUs.

·   Also, there is a new Farm Science Review web application for your smartphone or tablet. This is the second year for the FSR app, which includes general show information, a full schedule, comprehensive maps and exhibitor information.

While on your device, direct your mobile browser to http://go.osu.edu/SRg and download the app. On most phones and tablets, you can simply bookmark the page for future reference. This should reference all of the talks at the Gwynne, Small Farms and Agronomy Demonstration Plots.

Agronomic Crops Team Schedule for Farm Science Review

There is a chance for one more field day, that lasts for three days – the September 17, 18 and 19 OSU Farm Science Review at the Molly Caren Agricultural Center near London Ohio. One way to learn is to see first hand the research that the Agronomic Crops Team conducts. The Agronomy demonstration plots are to the east of the exhibit area, on the path from the parking lot to the main pedestrian entrance at Gate C. We’ll be there all day, all three days from 8AM to 5PM. Look for the tent, stop and visit.

2013 highlights

·  Nutrient management – from manure to Phosphorus and Nitrogen placement; stop by to talk with us about how we can better place N & P to reduce losses.

·  Soybean weed control – we have had some problems again this year, there is no new technology to rescue us and now we have these pesky pigweeds moving in.

·  Corn management for high yield – higher populations, narrow rows, sugar – but which sucrose or dextrose?

·  Maximizing soybean yield – maybe we just need to mind the basics.

·  Origins of modern soybean genetics – it’s not all about Roundup Ready

·  North America’s most exported crop – from Teosinte to modern hybrid corn production – the history of corn; and where do those hybrids come from?

·  Bio-fuel alternatives with Dennis Pennington from Michigan State University’s Kellogg Center demonstrating the bio-energy pellet machine each day at 9:30 and 1:30.

·  Soybean aphid resistance, and other late season insect pests

·  Disease control of corn - and things that can go wrong

·  Sign up for the C.O.R.N. newsletter here, too.

In the Agronomy Demonstration Plots – new with scheduled speakers at 10AM and 2PM each day, and individual plot tours with OSU Extension field specialists almost any time you stop by.

Come to hear the speakers, and then wander the plots to discuss our research. Past visitors like our plots and discussion, but this year we added scheduled talks each day so you can get your information directly from the agronomic crops specialists.

·  Kiersten Wise, Purdue University Plant Pathologist – on September 18th.

·  Mark Loux, OSU Extension Weed Specialist – will discuss pigweed species in Ohio and why we have concerns

·  Amanda Douridas & Glen Arnold – Manure Management Specialists will discuss manure placement for optimum crop needs

·  Greg LaBarge – Agronomy Field Specialist will give an update on P management in Ohio and placement

·  Grace Bluck – OSU Horticulture & Crop Science will discuss hail injury and recovery

·  Alex Lindsey also with H&CS will be demonstrating hardware that can detect stress in corn – come see if a million dollars worth of equipment can tell us more than our eyes can.

·  And more across all three days with Anne Dorrance with soybean diseases, Pierce Paul on wheat diseases and late season corn disease concerns and Ron Hammond on late season insect pests and their impact on yield along with Andy Michel on aphid resistance

Schedule of 2013 Farm Science Review Agronomic Crops Team Talks – in the Agronomy Plot Demonstration Area. CCA CEUs approved.

Tuesday, September 17th

9:30     Dennis Pennington      Bio-energy Pellet Demonstration

10:00   Ron Hammond           Late season insect pest on soybean: Bean leaf beetle and stink bug evaluation

10:30   Amanda Douridas       Corn application timing and methods for manure

11:00   Glen Arnold    Using livestock manure nutrient to fertilize corn, wheat and alfalfa

1:30     Dennis Pennington      Bio-energy Pellet Demonstration

2:00     Anne Dorrance            Season long impacts of soybean diseases

2:30     Grace Bluck    Soybean Health: Fungicide Application, Sugar Application, and Hail Recovery

Wednesday, September 18th

9:30     Dennis Pennington      Bio-energy Pellet Demonstration

10:00   Mark Loux      Pig(weed)s in Ohio: Will the big, bad wolf blow that door down?

10:30   Kiersten Wise  Managing diseases long term in the eastern Corn Belt

11:00   Clif Little        Summer and fall forage solutions

1:30     Dennis Pennington      Bio-energy Pellet Demonstration

2:00     Andy Michel   Aphids in Ohio, and finding plant resistance genes

2:30     Greg LaBarge Soil test P stability and managing to the critical level

Thursday, September 19th

9:30     Dennis Pennington      Bio-energy Pellet Demonstration

10:00   Greg LaBarge Low hanging Fruit in Managing DRP and edge of field losses

10:30   Alex Lindsey  How Can We Quantify Plant Stress? Current Techniques to Measure Environmental Stress

11:00   Steve Prochaska          Wide Row Wheat: with an eye toward Intercropping

1:30     Dennis Pennington      Bio-energy Pellet Demonstration

2:00     Pierce Paul      Corn disease concerns for fall 2013

2:30     Alex Lindsey  Drought Tolerance Testing in Corn

Fall Harvest Considerations for Alfalfa

A popular question as we enter September is: What is the last date to harvest alfalfa?  Unfortunately, there is not one single right answer to this question.  It really depends upon a number of risk factors and how comfortable the alfalfa grower is with varying degrees of risk.  Based on risk, there are guidelines that can be used to help determine a last fall harvest date. According to the Ohio Agronomy Guide, the last regular season harvest dates vary depending upon the area of the state and are September 7 for northern Ohio, September 12 for central Ohio and September 15 for southern Ohio.  These guidelines are based on avoiding a fall harvest during the late September through October period.  This period is termed the critical period because this is when forages are actively storing carbohydrate reserves in the crowns and roots.  Following this recommended last harvest schedule is a least risk, time-tested model.

There certainly are alfalfa growers who believe the Ohio Agronomy Guide fall harvest dates are too conservative.  Cherney and Kilcer from Cornell University wrote a newsletter article in 2000 on the topic of fall forage management.  In the article they say that research indicates the length of the harvest interval prior to fall cutting is more important than the actual date of fall cutting in terms of risk to an alfalfa stand.  Their advice is to provide a rest period of at least 6 weeks between the last two cuts of the season.  In a July 2012 Cornell newsletter, J. Cherney, D. Cherney and P. Peterson write about alfalfa fall harvest guidelines.  They review some research from Canada that links the carbohydrate reserves accumulated between a second and third cutting to growing degree day (GDD) accumulation.  That research showed that as long as there was a sufficient interval to accumulate 500 GDD between the fall harvest and the previous harvest, alfalfa could be cut during the critical period.  Put in terms of weeks, this matched up once again with a cutting interval of 6 to 7 weeks.  How dependable is this concept of harvest interval?  How relevant is this concept of cutting interval to last fall harvest in Ohio?

Last winter, alfalfa growers across the Upper Midwest   suffered the worst winter stand loss of alfalfa in recent memory with millions of acres of alfalfa lost.    So, what went wrong? University of Wisconsin Extension forage specialist Dan Undersander chalks up the stand losses to poor energy reserves going into the winter.  The winterkilled fields had been managed quite intensively the previous year (2012) when above-normal temperatures and drought stress caused the crop to flower sooner than normal and consequently, stands were cut early before carbohydrate reserves were adequately replenished. Many fields were cut on only three-week harvest intervals. The intensive cutting schedule made it hard for the alfalfa to survive the very long winter that followed.  There simply was not enough energy for plants to overcome the weather conditions and have enough reserves to resume normal growth when sustained growing conditions finally arrived in May this year.

The harvest interval concept as a guideline for fall alfalfa cutting management has not been tested further south where fall regrowth may be more significant.  So in addition to the uncertainty of winter and succeeding spring conditions, what happens in the fall after alfalfa is cut?  If regrowth starts it must continue until the carbohydrate reserves used to generate that regrowth are replenished.  So, while the harvest interval concept may have some merit, it is not without risk and even in those articles from New York the authors stated that the other key factor besides a long enough cutting interval is that the alfalfa stand must be healthy if it is cut during the critical period.

Factors that help to determine stand health include disease resistance, protection from insects, age of stand, cutting management and fertility.  In the Cherney and Kilcer article, they state that alfalfa varieties with improved disease resistance enables those varieties to be more tolerant to negative effects of a fall cutting because there is less total stress on the plant.   Any of the newer varieties of alfalfa have good resistance to the major alfalfa diseases.  Research has shown that alfalfa is very sensitive to soil fertility.  High soil potassium can increase plant health and plant tolerance to fall cutting effects.  A high soil pH of 6.8 to 7.0 will also reduce the risk of fall cutting.  Stands under 3 years of age are more tolerant of fall cuttings as compared to older stands. Protection from potato leafhopper stress during the year is also important for maintaining strong and vigorous plants that will be better able to withstand a fall cutting stress.   

A significant risk factor that must be considered when making a decision about a final fall harvest is the number of times the stand has been harvested.  Alfalfa that has been cut three or more times before a fall harvest has a higher risk factor for injury due to fall harvest.  A final factor is soil drainage.  Alfalfa stands on well drained soils tolerate later fall cuttings better than alfalfa on moderately or poorly drained soils.

The bottom line is this: Most years in Ohio growers can probably get away with cutting during the fall without severe injury, but it is very probable that fall harvest robs yield next year and it always increases risk of winter damage if the cutting date is such that alfalfa regrows without sufficient time to recharge what it used for that fall regrowth.  Taking all risk factors into consideration, the worst time to harvest in Ohio is most likely between September 25 and October 15. If you do decide to cut during the fall critical period, leave several strips of alfalfa uncut in different parts of the field so you can compare the vigor of cut and uncut plants next year.           

For more information about fall alfalfa harvests contact a member of the OSU Integrated Forage team.

"Nosing Back" and "Zipper Ears" in Corn

Recently I’ve received reports of corn ears exhibiting “nosing back” symptoms. This condition, also referred to as “tip-back”, or “tipping back”, is not unusual and we encounter it every year although the magnitude of the problem varies greatly. Tip dieback is associated with unfertilized ovules and aborted kernels at the ear tip. Even in fields that receive timely rains, corn ears with unfilled tips may be common. No kernels may be evident on the last two or more inches of the ear tip. Several factors may cause this problem. The ovules at the tip of the ear are the last to be pollinated, and under stress conditions only a limited amount of pollen was available to germinate late emerging silks. Pollen shed was complete or nearly complete before the silks associated with the tip ovules emerge. As a result, no kernels form at the ear tip. Severe drought stress resulted in slow growth of the silks that prevented them from emerging in time to receive pollen. This was evident in many drought stressed fields in 2012. Uneven soil conditions and plant development within fields may have magnified this problem. Pollen feeding and silk clipping by corn rootworm beetles and Japanese beetles also contribute to pollination problems resulting in poorly filled ear tips.

 

Tip Dieback

 

Incomplete ear fill may also be related to kernel abortion. If plant nutrients (sugars and proteins) are limited during the early stages of kernel development, then kernels at the tip of the ear may abort. Kernels at the tip of the ear are the last to be pollinated and cannot compete as effectively for nutrients as kernels formed earlier. Heat and drought (as well as other stress conditions, such as nitrogen deficiency, hail, and foliar disease damage) may cause a shortage of nutrients that lead to kernel abortion. Periods of cloudy weather following pollination, or the mutual shading from high plant populations can also contribute to kernel abortion. Kernel abortion may be distinguished from poor pollination of tip kernels by color. Aborted kernels and ovules not fertilized will both appear dried up and shrunken; however aborted kernels often have a slight yellowish color.

 Are unfilled ear tips a major cause for concern? Not always. In many cornfields this year, favorable growing conditions may have resulted in a larger number of potential kernels per row than normal. So even if corn ear tips are not filled completely, due to poor pollination or kernel abortion, yield potential may not be affected significantly, if at all, because the numbers of kernels per row may still be above normal. The presence of ears consistently filled to the tip may actually indicate that a higher plant population is needed to optimize yields.

Another ear development problem involving poor kernel set that’s been getting more attention recently is “zippering” in which corn ears exhibit missing kernel rows (or parts of rows) often on the side of the cob away from the stalk that gives sort of a zippering look on the ears”.  The zippering often extends most of the cob’s length. Zippering is often associated with a curvature of the cob, to such an extent that zipper ears are sometimes referred to as "banana ears". This ear deformation is caused by the absence of kernels on one side of the cob coupled with the continued development of kernels on the other side that "force" the cob to bend or curve.

Zippering is due to kernels that are poorly developed and/or ovules that have aborted and/or not pollinated along some length of the ear. Affected ears are often associated with corn plants which have experienced drought stress during early grain fill; cobs associated with the zippering are usually smaller than normal and poor tip fill is often present. Recent OSU studies indicate that some hybrids are much more susceptible to zippering than others and that zippering among such hybrids is more pronounced at higher seeding rates. In studies in which corn plants have been subjected to severe defoliation during the late silk and early blister stages, we’ve observed the resulting ears to show zippering, which suggests that a sudden reduction in photosynthate supply may be a factor. The zippering did not occur when plants were subject to similar defoliation at the milk or dough kernel development stage.

Zipper Ears

Abnormal Corn Ears

Farmers frequently encounter abnormal corn ears in their fields when the crop has experienced stress conditions, such as drought, temperature extremes, disease, insect injury, or misapplied chemicals. These abnormalities often affect yield and grain quality adversely. We have prepared a poster (Fig.1) highlighting ten abnormal corn ears with distinct symptoms and causes. The purpose of the poster is to help corn growers and agricultural professionals diagnose various ear disorders. A reduced 11 x 14 inch version of the poster is available for online at:

https://agcrops.osu.edu/specialists/corn/specialist-announcements/Abnorm...

The OSU College of Food Agric. and Env. Sci. Communications & Technology section (contact information below) has 26 x 33 inch copies of the poster available for distribution. The poster is printed on plasticized coated paper for durability. Poster cost is $11.25 plus shipping. Ask for “Abnormal Corn Ears” poster” ACE-1.

The Ohio State University

College of Food Agric. & Env. Sci.
Communications and Technology
Media Distribution
216 Kottman Hall, 2021 Coffey Road
Columbus, OH 43210-1044
E-mail: pubs@ag.osu.edu

Order Online: http://estore.osu-extension.org/
Phone 614-292-1607
Fax     614-292-1248

 

 

Archive Issue Contributors: 
Archive Issue Authors: 
Topics: 
Corn Silage
Nutrient Management

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.