Answers to corn harvest questions

Brian Essinger, DeKalb/Asgrow Territory Manager, has been fielding questions from farmers in northwest Ohio based on what they have been seeing in fields this fall. Here are some of the most common questions and Essinger’s research-based responses.


Question 1: Have you seen much ear drop?


Ear drop can be genetic, but more than likely what you are seeing this year is caused by environmental stresses. Ear drop problems will vary by environment (i.e. planting date, soil type, and in field stresses). All of the agronomic occurrences are related to the late planting timing, high heat and drought during pollination, and the extended cool wet weather in late August and September. Combine these stresses with the uniqueness of each field and we will get anomalies or scenarios that are not ideal or sometimes unexplainable. Initial reports are they may not have impacted overall yields as much as we thought, but have caused other issues. More specifically, here are some environmental stresses that can cause ear drop:

1. The most common/severe cause is extreme high temperatures during R1 (Silking). High temperatures at this time can cause a weak shank.

2. Drought Stress and premature plant death can also result in diminished shank strength.  Ear shanks can be cannibalized for carbohydrate production just like stalks.

3. Fungal infections, which develop late in season, can also lead to shank deterioration, particularly just before harvest.

4. Insects like European corn borer can tunnel into the shank, and weaken it in conventional or refuge products.


Question 2: What causes Ear Molds?  Are there hybrids that are more focused on grain quality, rather than flat yield?


Ear molds are a direct result of a combination of environmental stresses. Yes, some hybrids have better grain quality/ear disease ratings than others. However this year, quality issues were more a factor of weather, timing and stresses than product. Here are the various stages/stresses that need to be present to have ear rots.

1. Ear disease starts back at pollination. It is dependent upon the number of spores of Diplodia, Fusarium, and Gibberella in the air when the seed tubes emerge for pollination.

2. Stresses like heat, drought, nutrient deficiencies and bird damage also impact ear/kernel development and add to the possibility of ear disease development.

3. Finally, if weather conditions are right (cool, wet, wet, dewy) late season the ear diseases will manifest themselves.

Therefore disease susceptibility is more a factor of timing and weather than hybrid susceptibility, although some products are a little more susceptible it is still about timing.  See Information on ear diseases attached above.


Question 3: Does Sprouting affect quality?


Sprouting should not affect feed or grain quality. A little starch may be used in the sprout, but not enough to cause major feed loss or deterioration. During harvest, these sprouts will be knocked off and should not affect grain quality much at all. It is more a cosmetic problem in the field than a major problem in grain/feed quality.


Question 4: Do you think sidedressed nitrogen is causing some of the late maturing this year even in the earlier maturity, or was it just the weather pattern?


First of all, the slowness or delayed drying is a direct impact of the rains and cool temperatures in late August and all of September. In fact, the warm temperatures in the last couple of weeks have matured and dried the corn in some instances by 8-10 points of moisture. Even after the late start with the increase of GDU’s throughout the summer, we were in good shape as far as maturity is concerned up until late August. Again, drydown is a factor of environment, but most of the factors have well been out of our control in 2011.

As far as nitrogen is concerned, and this is my agronomic opinion, the key is to have enough for your yield and agronomic goals (i.e. stand, health, quality) no matter what you use.  This is not a macronutrient to skimp on since it is a key building block yield and overall agronomic strength. As far as type and timing, each operation has to determine what is best for them. I am a fan of NH3 (ammonia). I believe overall it is more stable than other types and in Ohio that is critical because of most of the clay based soils. Plus, I like the use of knives to open the soil when applying it. However, this does not mean it is the only viable source. You do have to weigh in the safety factors and practicality when handling ammonia and these should be first and foremost when making your decision.

Here are the practices I prefer and I am talking in ideals, but Nitrogen decisions must be based on what works best for your operation.

1. In an ideal world I would like to see 100 pounds of N at preplant, 30-45 pounds of N applied during planting, and 80-100 pounds of N sidedressed depending on yield goals.  This would feed the plant throughout all critical times of reproduction from V5-V8 (ear width determination), V10-V12 (ear length determination), then reproduction and fill.

2. If that is too many passes for your operation, I would put 45 pounds on at planting and 160-200 pounds sidedress.

3. If you preplant nitrogen in the spring use a nitrogen stabilizer like N-serve to maintain the maximum amount of N available to the plant throughout the season. I would still put on 30-45 pounds of N when planting, as the pre-plant N will be available like an early sidedress rather than early N when applied during planting.

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