Frost Damage Update: Prior to the Oct. 8 frost, I did a driving tour to check where any replant fields were at. I wanted to have an idea of what potential yield loss we were looking at in the area.  Around 85% of the corn surveyed in the York/Seward/Hamilton/Clay area pre-frost was in the ½ milk stage. Around 10% was ¼-1/3 milk stage while the remainder was either just at beginning dent or at ¾ dent.

So, I knew we were mostly looking at these stages when it came to yield loss when I wrote last week:

• Beginning Dent: Leaves & Stalk killed = 40% yield loss; Leaves only killed = 27% yield loss (23% via National Crop Insurance Services 100% leaf loss at this stage)
• ½ milk: Leaves & Stalk Killed = 12% yield loss ; Leaves only killed = 6% yield loss (8% yield loss based on National Crop Insurance Services 100% leaf loss at this stage)

Looking at fields this week, the top half of plants in all corn fields were frost damaged with leaves turning gray/green. Fields that were earlier than ½ milk and/or that had been recently irrigated before the frost, had green leaves from the soil line up to the ears. I also observed that most of the corn moved another 1/4 milk along from what I documented prior to Oct. 8. Milo fields also ranged in the amount of leaf area killed as one looked at canopies within fields. Soybeans that had leaves were protected by shelterbelt areas, but otherwise turned color for the most part. In a couple fields that were further behind, the pods/seeds are turning to a light green/yellow, so will see what happens with the bean color over time. Leaf area that was not killed in all these crops will succumb with expected temps Sunday-Tuesday.

With the winds last week, I was concerned about stalks and ears, as were a few people who asked me what it was looking like. I am concerned about stalk quality going forward. Thankfully, right now, stalks are holding up well. Tops blowing out is fairly hybrid specific or observed more in non-irrigated ground. Frost damage to premature corn can also lead to pinched ear shanks as the ears turn down prematurely, increasing the potential for ear drop. So far, fortunately also seeing ear shanks firmly attached with ears firmly attached in husks.

I know we want to get the corn as dry as possible in the field. Just want to caution you to keep an eye on the stalks and ears and plan to harvest at higher moistures if needed.

Grain drying resources with charts:

• Drying binned corn with natural air: https://cropwatch.unl.edu/drying-binned-corn
• Drying corn using heat: https://cropwatch.unl.edu/cw-09-11-3-drying-times-corn-heated-aeration
• Bin drying soybeans: https://cropwatch.unl.edu/bin-drying-soybeans

Would documenting test weights be of value to you? Was thinking about what could be learned with this frost. I can’t document yield loss because we don’t have any corn that wasn’t damaged, but I can document what happens with test weights. Wondering if the info. could be helpful in the future since I’m not aware of recent data? So, I plan to drive the same route as we get closer to black layer and grab ear samples for test weights. The only thing I won’t know is hybrids on all the fields, but will document them where I know them. If you’d like to help, if you knew where your corn was at pre-frost, simply add in what the test weight, moisture, and hybrid was at the following link and I’ll share the anonymous data after harvest: https://forms.gle/x9VhbyMeA5qNku1YA.  If you have other ideas how to improve this or something else I should be thinking about for information, please let me know!

Greenness remaining in fields varied depending on crop stage pre-frost and soil moisture level. Minimal greenness remained in non-irrigated (far-left) to green from the soil line to ears in the two right-photos. Ears are turning down in fields that were more impacted by frost and most likely we will see ears turning down more this coming week. Watch stalks for stalk rot and watch for potential ear drop in fields.

I didn’t pop into many soybean fields but this is the range of pods/seeds coloration that could be expected in those that were greener with leaves remaining on them. These beans were still filling and pods were changing color. Several sources say the seed greenness should lesson over time if the stem was not completely froze (which was observed this past week with green color lessening) and/or with aerated storage after 4-6 weeks.

Milo also showed damage to leaves but often remained green deeper within the canopy of fields as one went into the fields. Most of the milo was past hard dough stage pre-frost.

Other observations last week: Wasn’t happy to see ear worms survive the frost in some ears (but the ones I found didn’t survive me 🙂 ). Drifts of soybean leaves in ditches are a common site with the very windy days.