Corn observations: It seems amazing to me to be where we’re at with harvest and it’s only October 4th as I write this! Many farmers finished beans last week and started on corn. It’s a good feeling to be at this point; can also appreciate there’s been no rain and not a lot of breaks either. Please be safe!
This past week was spent taking corn notes and starting to harvest corn studies. Besides harvest stand counts, I also like to look at percent stalk rot in fields. This gives an idea regarding standability and harvest priority. To do this, I use a pinch test using my thumb and first finger to pinch the elongated first or second internode above the soil line on 20 plants in an area of the field. Stalks that are compromised will “give” or “crush”. Obtain a percentage for the number of stalks that do so. Quickly doing this in five areas of the field provides a better idea of stalk health and harvest priority. Stalk quality pinch test video at: https://youtu.be/7z75VN1c51Q. So far, much of the corn is standing well. I’m mostly finding compromised stalks on plants that had premature ear droop. It will be especially important to assess stalk rot for fields that had high southern rust pressure and weren’t sprayed with a fungicide.
Another observation is some weakened ear shanks, although I can’t say this is a problem yet or even widespread. Weakened shanks makes sense on ears that prematurely drooped as that ear shank collapsed. Things we know cause weakened ear shanks and ear drop include stresses like high heat and/or moisture stress around pollination, large ears after this type of stress due to long grain fill, fungal disease like Fusarium infecting the shank, and to an extent, genetics (regarding shank diameter size). As we think of this year, we had the July 8th wind storm shortly before tassel which caused additional stress on plants. Corn also had a long fill period creating larger ears. So again, not saying this is a problem, just something to watch.
Stress cracks and broken kernels are another thing to watch for and seek to minimize. We know this can occur during the grain drying process in the bin when high moisture corn is dried with high heat followed by rapid cooling. In one conversation this week, a farm family was wondering if there were conditions that led to more stress cracks to corn in the field this year. I really don’t know. Found one publication that said internal, invisible stress cracks can also occur during kernel fill as a result of high temperatures and/or high moisture. However, the focus of the publication was viewing cracks with other types of imagery instead of the physiology, so I don’t have more to share on that. Broken kernels can also occur with harvesting higher moisture corn (above 20%), particularly with too high of rotor speed. A handful of guys have mentioned seeing broken kernels as they’ve been harvesting above 20% and shared the combine adjustments they’ve made to minimize them, so thought it may be something to mention. Combine setup is not my expertise but with a quick search, there’s a number of YouTube videos and websites regarding reducing broken kernels that may be helpful.
Corn Drydown Calculator: If you’ve never seen it or used it before, Iowa State University has a neat tool that estimates corn drydown in the field based on weather forecast for a particular area. It’s called the corn drydown calculator and you can find it at: https://crops.extension.iastate.edu/facts/corn-drydown-calculator.
Land Leasing for Solar Development Oct. 9th: Just a reminder of this virtual seminar to be held October 9th from 11 a.m. to 1 p.m. You can register at https://go.unl.edu/solarleasing. This seminar is open to the public. Farmers, landowners, and their families in areas with potential solar development have much to consider and should consider attending. This webinar will give an overview of solar development and touch on major issues to consider when negotiating a solar lease agreement. More info. on this topic at: https://cropwatch.unl.edu/2020/considerations-leasing-land-solar-development.
Crop Update: In some ways it’s felt like a strange harvest season with how much of the area crop was harvested early due to storm damage and drought, but that’s also a blessing. It’s also been a blessing to have had surprisingly good test weights from some of the hail damaged corn and low mold damage reported thus far. There’s still a lot of harvest to go and I think stalk and ear rots are on the minds of us all.
I’ve been seeing more ‘less common’ ear rots this year and starting to receive questions on them. These include Nigrospora ear/cob rot, Cladosporium rot, and Trichoderma rot. These are caused by weaker fungi feeding on ears of plants that were stressed or killed prematurely. So hybrids that had problems with anthracnose top dieback, top leaf death, root rot issues, shortened husks with exposed ear tips, and hail/wind damage may have more problems with these diseases. Symptoms include when the cob feels rotted or falls apart when you break an ear in half. With Nigrospora, the kernels often have black spores on them and the spores can also be noticed on the cob pith as well. With Cladosporium and Trichoderma, the spores appear more green in color. None of the fungi causing these diseases have a mycotoxin associated with them, which is good. The diseases can create lighter test-weight ears and can create more chaff and dust during harvest due to the cobs falling apart. In storage, the biggest problems would be the fines, broken cobs, and extra chaff; keeping the grain below 15% moisture will stop fungal growth.
I’ve also had people asking for more specifics on conducting the pinch test to determine percent stalk rot in the field. Sometimes it’s easier to visualize this versus me keep writing about it. Thus, I created a very short video this week to hopefully help. One note is as you do this pinch test, the stalks may not completely crush, but a stalk with rot has a definite ‘give’ to it. You can view the video at: https://www.youtube.com/watch?v=7z75VN1c51Q.
For those who left hail-damaged soybean standing in fields with yields less than 5 bu/ac, some have asked about grazing those acres. For whole fields, we were recommending seeding a cereal into them (like rye at this point) just to offset the fat content of any remaining beans and provide some cover on the ground. That’s still a possibility for those interested in doing this. Some have also asked about grazing the soybean acres adjacent to seed corn residue without adding in a cover crop. That could be an option too and we don’t anticipate problems with that situation. When grazing seed corn or corn residue in any fields, it will be important to determine amount of ear loss on the ground prior to grazing. A way to do this is to measure off 100 feet and count the number of ears you find within that distance; do this 3 times throughout the field (for a total of 300 feet). Add the total number of ears found in 300 feet. Then, assuming each ear is about 0.5 bu, multiply the total number of ears by 0.5 to determine the average bushels on the ground in the field. Normal grazing management can be used if the total is 10 bu/ac or less on the ground. If more than that, different management needs to be considered and the following is a good resource for those considerations: https://go.unl.edu/8j4n.
For those asking about wheat varieties for Eastern Nebraska, the following resource may be of benefit to you at: https://cropwatch.unl.edu/2018/winter-wheat-varieties-eastern-nebraska-fit.
Also, Aaron Berger, Nebraska Extension Educator who conducts podcasts for the UNL Beef website, recently interviewed Chad Dane, a Clay County farmer. You can hear this podcast on “A Row Crop Farmer’s Perspective on Cover Crops and Cattle Grazing” at: http://s3-us-west-2.amazonaws.com/unlbeefwatch/2018/Sep_2018_Chad_Dane.mp3.