Estimating Yield Losses in Stressed Corn Fields

Source: Dr. Peter Thomison, OSU Extension

Drought stressed corn near tassel emergence

Many corn fields are still silking (and some are just past the mid-vegetative stages)….so, it may seem a little early to discuss estimating grain yields. However, according to the most recent  NASS crop report, for the week ending Aug. 8, 2019,  25% of the corn crop has reached the dough stage (compared to 63% for the 5 year average). Corn growers with drought damaged fields and late plantings may want to estimate grain yields prior to harvest in order to help with marketing and harvest plans. Two procedures that are widely used for estimating corn grain yields prior to harvest are the YIELD COMPONENT METHOD (also referred to as the “slide rule” or corn yield calculator) and the EAR WEIGHT METHOD. Each method will often produce yield estimates that are within 20 bu/ac of actual yield. Such estimates can be helpful for general planning purposes.

THE YIELD COMPONENT METHOD was developed by the Agricultural Engineering Department at the University of Illinois. The principle advantage to this method is that it can be used as early as the milk stage of kernel development, a stage many Ohio corn fields have probably achieved. The yield component method involves use of a numerical constant for kernel weight which is figured into an equation in order to calculate grain yield. This numerical constant is sometimes referred to as a “fudge‑factor” since it is based on a predetermined average kernel weight. Since weight per kernel will vary depending on hybrid and environment, the yield component method should be used only to estimate relative grain yields, i.e. “ballpark” grain yields. When below normal rainfall occurs during grain fill (resulting in low kernel weights), the yield component method will OVERESTIMATE yields. In a year with good grain fill conditions (resulting in high kernel weights), the method will underestimate grain yields.

In the past, the YIELD COMPONENT METHOD equation used a “fudge factor” of 90 (as the average value for kernel weight, expressed as 90,000 kernels per 56 lb bushel), but kernel size has increased as hybrids have improved over the years. Dr. Bob Nielsen at Purdue University suggests that a “fudge factor” of 80 to 85 (85,000 kernels per 56 lb bushel) is a more realistic value to use in the yield estimation equation today. https://www.agry.purdue.edu/ext/corn/news/timeless/YldEstMethod.html

According to Dr. Emerson Nafziger at the University of Illinois under current drought stress “…. If there’s a fair amount of green leaf area and kernels have already reached dough stage, using 90 [as the “fudge-factor “] might be reasonable. It typically doesn’t help much to try to estimate depth of kernels at dough stage, when kernel depth is typically rather shallow anyway, especially if there are 16 or more kernel rows on the ear. If green leaf area is mostly gone, however, and kernels look like they may be starting to shrink a little, kernels may end up very light, and using 120 or even 140 [as the “fudge-factor”] might be more accurate”. http://bulletin.ipm.illinois.edu/article.php?id=1695.

Calculate estimated grain yield as follows:

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Hay and Straw Barn Fires a Real Danger

Jason Hartschuh, CCA, Mark Sulc, Sarah Noggle, David Dugan, Dee Jepsen, OSU Extension

Usually, we think of water and moisture as a way to put a fire out, but the opposite is true with hay and straw, which when too wet can heat and spontaneously combust. Most years this is more common with hay than straw because there is more plant cell respiration in the hay. This year the wheat is at various growth stages and straw seem to have more green stems than normal. When baled at moistures over 20% mesophilic bacteria release heat-causing temperatures to rise between 130⁰F and 140⁰F. These bacteria cause the internal temperature of hay bales to escalate, and can stay warm for up to 40 days depending on the moisture content when baled. If bacteria die and the bales cool, you are in the clear but if thermophilic bacteria take over temperatures can rise to over 175⁰F.

Assessing the Fire risk

  • Most hay fires occur within the first six weeks after baling
  • Was the field evenly dry or did it have wet spots
  • Were moistures levels kept at 20% or less
  • If over 20% was hay preservative used

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Knox County Soybean Starter Fertilizer Trial

A BIG thank you to David & Emily Mitchem for allowing me to put my Soybean Starter Fertilizer trial on their farm this year!

 

The results are listed in the tables below.

The 2018 report is now available in both a print and e-version. To receive a printed copy, stop by the Knox County Extension office.  The e-version can be viewed and downloaded here at go.osu.edu/eFields.

Dealing with the Weather and Unharvested Crops

Source: Penn State Extension (Edited)

WHAT A FALL!!!  According to the November 26 Crop Weather Report, approximately 14% of corn and 10% of beans still in the field.  The average moisture content of corn harvested last week was 17 percent and the average for soybeans was 16 percent, how big of a concern is this?

The weather continues to be unpredictable and give challenges to operators with grain and crops still in the field. Snow and ice over the last couple weeks have just been the latest in a long list of hurdles that growers have had to overcome this season. With some careful thought and planning you can still have a successfully harvest.

Having corn in the field now can be a double-edged sword. The longer it stays out, the dryer the corn will be when harvested, thus decreasing your drying costs. However, there is a higher risk of yield loss the longer the corn stays unharvested. Research on winter corn drydown showed that over a five-year span, corn grain would lose roughly 40% of its moisture between the months of October and December, when left in the field. The tradeoff is that we cannot anticipate the weather. The same study found that a single year yield decreased by 45% and another year decreased by only 5%.

Another concern of unharvested corn could be disease and mold. When discussing disease and mold, snow and ice pose no more danger to your crop than rain does. A positive of this situation is that the lower temperatures could have a limiting effect on pathogens’ ability to incubate or develop. A drawback of having laying snow is an increased opportunity for lodging. This year we have already seen a lot of lodging due to stem rots and adding snow to the mix may increase this risk. The risk of lodging is even further increased when coupled with winter winds and snow and ice to come. The takeaway is that disease and mold issues should not be your largest concern right now.

If you have a large amount of stock rot and lodging, harvesting as soon as possible will be best for a successful harvest. If your corn crop has lodged, one thing to remember is that this is not a usual harvest. Special consideration and care must be taken to get acceptable yields, which means slowing down and using caution. A few other options you have for getting a better harvestable yield are combining in the opposite direction, or “against the grain.” This will allow the head to get under the crop and lift it up. Another option is to use a corn reel. A corn reel is a specialized piece of equipment that mounts on the top of your corn head and uses rotating hooks to lift the corn and allow the head to get under the lodged crop.

The last concern is compaction and rutting of fields … Who Doesn’t Have Compaction Issues This Year??  Compaction will linger for years and will require attention to avoid problems with next year’s crop.

 

Drying and storing wet soybeans

Source: Michael Staton, Michigan State University Extension

Due to the cool and wet conditions, soybeans harvested at this time of the year will need to be dried on the farm or at the elevator. Some elevators will accept soybeans up to 18 percent moisture while others will reject loads that are above 15 percent moisture. Contact your elevator prior to delivery and understand their discount schedule. Information on understanding soybean discount schedules is available in “Understanding soybean discount schedules” from Michigan State University Extension.

Commodity soybeans used for domestic crush or export can be dried using supplemental heat. However, food grade and seed beans should not be dried with supplemental heat. Proper management is essential to minimizing damage when using supplemental heat. Keep the drying temperature below 120 degrees Fahrenheit.

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Understanding soybean discount schedules

Source: Michael Staton, Michigan State University Extension

 

Every elevator that receives soybeans has a discount schedule. Discount schedules are important because they communicate how and when various shrink factors and discounts are applied at delivery. Discount schedules vary from elevator to elevator and can be somewhat confusing. This article lists and explains the major shrink and discount factors pertaining to soybeans and provides examples of shrink and discount calculations.

Test weight

Test weight is a measure of density (mass/volume) and is measured in pounds per bushel. The standard test weight of 60 pounds per bushel is always used to convert the scale weight of soybean loads to the number of bushels contained in the load. This is true even if the actual test weight of the load is lower than 60 pounds per bushel. Therefore, test weight does not impact the number of saleable bushels harvested from a defined area (acre or field). However, most grain buyers will begin discounting soybean loads when the test weight falls below 54 pounds per bushel. Discounts are applied to the gross weight of the load before shrink factors are applied. The only advantage of having test weights higher than 54 pounds per bushel is that the beans will take up less volume in storage and during transportation.

Read more click here.

 

2018 Ohio Corn Performance Test Preliminary Results Now Available On-Line

Results from the 2018 Ohio Corn Performance Test are now available on line at:  http://oardc.osu.edu/corntrials

Single and multi-year agronomic data is currently available for the Southwest / West Central and North Central / Northeast regions. Upper Sandusky will be harvested when field conditions allow. Results for Upper Sandusky and the Northwest region summary will be updated immediately after harvest. The results can be accessed by following the links on the left side of the page.  Information regarding the growing season, evaluation procedures and traits will be available soon.  Additional hybrids will be added as soon as marketing information becomes available, as will the combined regional tables (which are especially helpful in assessing hybrid performance across locations).