I’m so grateful that harvest is mostly complete at this point! When so much of the crop was replanted in late June/early July, I wasn’t anticipating harvest to get rolling till mid-November for the replant crop. The early frost ended up being beneficial in that way. With Thanksgiving approaching this week, I realized how much I needed to take time and reflect on the year; perhaps you do too? I realize many want to forget it, but it can be healing to think through what one experienced and look for the positives amid the challenges. We ran from what seemed to be one issue to another which led to an extra exhausting year with minimal time to process. I’m not ready to share thoughts yet, but it has been helpful for me to reflect. Hoping you can take time this Thanksgiving to reflect on the blessings amidst the hard things. There truly are so many! Wishing you and your family a blessed Thanksgiving!
Thanksgiving resources: For Thanksgiving turkey prep, fun recipes, and family activities, check out: https://food.unl.edu/article/thanksgiving-central. En español: https://go.unl.edu/z7di. My colleague Brandy VanDeWalle also shares some gratitude research in this post: https://vandewalleviews.com/2022/11/04/gratitude-improves-health-well-being/.
Returning to the Farm Workshop Dec. 9-10 at Holthus Convention Center in York: Only 50% of farm families have an estate plan in place. Billions of dollars will be transferred in the next 10 years in agriculture. Does your family have a plan in place to ensure that assets are transferred the way you desire? Being in Extension, I’ve heard and watched stories of heartbreak when one generation passed and the next wasn’t able to farm or ranch on ground the way either generation hoped. It’s happened in my family and perhaps some of you have experienced this too? So much of this comes down to communication. Most of us don’t communicate well and sometimes we need tools to help. Legal tools can then help with putting communicated goals and desires into place.
I highly recommend this workshop! It assists families and agricultural operations with developing financial plans and successful working arrangements to meet their unique needs. It will guide families in developing estate and transition plans, setting personal and professional goals and improving the communication process between family members. Sometimes the greatest barriers in life are our ability to communicate effectively with each other. As I’ve sat in the room during these workshops, I’ve watched barriers break down as different members listened long enough to learn what another person was saying (or not saying). I’ve watched a neutral environment where hard things were discussed and honesty was shared.
It really is intended for multiple generations to attend together. My colleagues have families work through scenarios/questions as multiple generations set around tables…things like what happens if different people pass unexpectedly, what happens in the event of a divorce or remarriage and what does asset transfer look like if that happens, who is all included and who isn’t included, fair and equal and are they the same, etc. My colleagues share numerous genuine stories, both humorous and hard, to drive home points. And, I’ve watched the different families represented in the room become friends, bouncing ideas off each other throughout the workshop and staying in touch months and years later. The workshop fee is $70 per person which includes meals and all the materials. It also includes two follow-up virtual workshops in the evenings on Jan. 12 and Feb. 2. Registration is due by early Dec. With this opportunity so close and with the main speaker and farm transition educator, Al Vyhnalek planning to retire this coming spring, I truly hope your family can take advantage of this! More info: https://cap.unl.edu/rtf22.
This week, I’m sharing information I learned at last week’s weed science school. One thing that was new to me, perhaps I should’ve known it but never really thought about it, waterhemp is a shade tolerant plant! We talk about palmer being so incredibly efficient with sunlight that I never thought about waterhemp being so efficient in the shade.
Dr. Kevin Bradley, weed scientist at the University of Missouri gave a great presentation. He had three main points which I share below.
1-More complex herbicide labels: get used to new labels for the future. Those who read the new Enlist® label would be more familiar with them. The labels are based on hydrologic soil groups (determined by soil texture which influences water infiltration and holding capacity). Depending on those hydrologic soil groups, the land manager/applicator needs to meet a minimum number of credits specified by complying with various management practices. This is similar to requirements EPA was proposing in their review of atrazine. Kevin shared this appears to be the way new labels will be formulated for the future.
2-Integrated approaches for weed control: ones he mentioned included cover crops, robots, releasing sterile weed pollen, electrocution, flaming, tillage practices, crop rotation, and chemicals. He did some work with Weed Zapper™ on electrocution of weeds. It has a copper boom attached to the front of the tractor which electrocutes any plant it contacts with up to 15,000 volts. It does this with a 110,000 watt generator attached to the back of the tractor. He shared that it had the best application on weed escapes later in the season that were at flowering or beyond (as a seed control mechanism) vs. trying to control smaller weeds. It provided decent control of marestail, giant ragweed, and waterhemp but not palmer and grasses. His team looked at any impacts to seed viability later in the season. On waterhemp with viable seed, the electrocution reduced that seed viability by 67%.
He also shared on combine seed destroyers where companies are hoping to provide this technology as an add-on feature to kill weed seed. He shared Redekop™ has a deal with Deere in Canada while Seed Terminator™ is planning to work with all brands right now. In the south where there’s typically green palmer at harvest, he said there’s an issue with clogging when using seed destroyers but didn’t see that issue as much in Missouri. His team put cameras on the ground and on the combine to show how it worked and they also collected seed during harvesting. The video from the cameras showed around 30% of weed seed shatters prior to entering the combine header…so there’s a portion that will never have a chance to be destroyed. However, it did an incredible job of separating weed seeds and funneling them into the seed destroyer where damaged waterhemp seed exiting the combine ranged from 66-83%. Across the 7 locations over two years, fuel consumption was 3 gal/hour greater, engine load was 5.6% higher, and speed was 0.24 mph slower when the Seed Terminator™ was on. They saw a significant reduction of waterhemp in the soil. It just depended on if it took 1 or 2 years to achieve it.
3-Zero tolerance for resistant weeds was an interesting topic to discuss with the audience. Ultimately, he was sharing that we’re in a new era of resistant weeds in which plants are able to break down the herbicide at increased rates using ‘metabolic resistance’. I need to dig into this to better understand these mechanisms, but he talked about ‘target site resistance’ where weeds in the 1990’s-early 2000’s conferred resistance by overcoming a specific site of action so the herbicide couldn’t bind. Since 2010 through today, weeds are able to use ‘metabolic resistance’ in which they can confer resistance to other herbicides in same group and possibly to herbicides in other groups. No one had good answers on how to get to a ‘zero tolerance for resistant weeds’ but one thing we all agreed upon was that it would take integrated approaches in order to do so.
Fall Herbicide is one management tool besides seeding small grains to control winter annual weeds and marestail (horseweed); it may not be necessary for every field. It’s important to scout fields for current weed pressure. Also consider targeting fields that have a history of winter annual weeds or marestail. Nebraska research shows up to 95% of marestail germinates in the fall, so fall application can aid management. Most products contain 2,4-D and/or dicamba. Tank-mixing a residual herbicide with a burndown product will improve marestail control because the residual activity will control marestail emerging after herbicide application.
Some winter annual weeds also serve as hosts for pathogens like soybean cyst nematode (SCN): purple deadnettle (strong host), henbit (strong host), field pennycress (moderate host), shepherd’s-purse (weak host), small-flowered bittercress (weak host), and common chickweed (weak host). SCN can reproduce in the field on henbit and purple deadnettle. We have no research to show that a fall application helps with palmer even though some feel it does.
Regarding temperatures, Dr. Amit Jhala has shared the ideal temperature for applying most post-emergence herbicides is between 65°F and 85°F. Herbicides can be applied at 40°F to 60°F, but weeds may be killed slowly. When the temperature is below 40°F for an extended time after burndown, weed control will most likely be reduced, specifically for a systemic burndown herbicide such as glyphosate. Additionally, weed control may be reduced under cloudy conditions following an initial temperature drop below 40°F. With late-fall herbicide applications be sure to add labeled adjuvants to improve herbicide efficacy.
Frosts of less than 25°F usually cause leaf damage to annual plants, making them poor targets for herbicide applications; however, winter annual weeds may tolerate a frost up to 20°F and continue growing when conditions improve, with little tissue damage. After weeds experience frost, active growth may not begin again for a few days. Growers should wait until new leaf tissue is produced, scout the field, and then consider applying herbicide. Generally, this would be when nighttime temperatures are 35°F or greater and daytime temperatures are at least 50°F for two consecutive days. Additionally, sunshine is needed for plants to recover.
Grazing Restrictions: Be sure to check labels for any grazing restrictions if livestock will graze cornstalks after a fall herbicide application (I’ve added photos of the grazing restrictions from the 2022 Weed Guide on my blog jenreesources.com). If the label doesn’t specify and you want to be on the safe side, a rule of thumb is to use the pre-harvest interval for the amount of time to wait before grazing stalks.
Water Testing Kits from UBBNRD: The following is a small excerpt from the UBBNRD Blueprint newsletter on this helpful program for rural residents. For the full article and information, please see: https://www.upperbigblue.org/%E2%80%8B-free-water-quality-test-kits-offered-rural-residents. “Consuming water with elevated levels of nitrate-nitrogen can have significant health risks, especially for younger people. (EPA guideline for safe drinking water is less than 10 parts per million of nitrate.) Annual testing of your water is an important way to protect the health of everyone in your home—and a new test kit now available through the Upper Big Blue Natural Resources District makes that even easier to do. Thanks to a partnership with the University of Nebraska Lincoln, the Upper Big Blue NRD can now mail simplified at-home test kits to district residents for free. To request a kit, call (402) 362-6601 or email email@example.com with your home mailing address. The at-home kits are not as sensitive as having a sample tested in the lab, but they do provide a simple way to determine if additional testing is required to identify what further steps need to be taken to improve drinking water quality, such as installing a reverse osmosis filter.”
2022 Nebraska Ballot Initiatives are explained by Dr. Dave Aiken in this document https://agecon.unl.edu/2022-nebraska-ballot-issues and webinar https://go.unl.edu/n2pw.
Grateful to hear the corn moisture is dropping and to see more replant corn being harvested! As November 1st is around the corner, some may be thinking about fall fertilizer. It’s important to consider soil temperatures regardless of the date one can apply fall fertilizer in area NRDs. Soil microbial activity and the conversion rate of ammonium to nitrate is very low when the soil temperature is less than 50oF. Thus, apply anhydrous ammonia (and manure) when the soil temperature at the 4” soil depth is below 50°F and trending cooler. We’re currently hovering above that mark and probably will be above it with the warmer air temperatures this week. You can view soil temps at: https://cropwatch.unl.edu/soiltemperature.
With the dry conditions, make sure there’s a good seal. One may also wish to consider if the anhydrous is deep enough and consider how it may impact your seed zone next spring if we remain in dry conditions. Be aware that soil nitrates are typically higher than normal after a dry growing season, especially in non-irrigated fields and even more so in non-irrigated fields that had wildfire damage.
As one looks at soil test results this fall, also be aware that soil pH and potassium (K) results are often lower than expected due to dry conditions, particularly in non-irrigated situations. It is true that below-normal yields result in lower phosphorus and potassium removal from the soil. However, as Dr. Antonio Mallerino from ISU shares, “a couple of processes may counteract this possible increase and most likely will result in lower soil-test P and K results than expected.
- Below normal rainfall from the time of physiological plant maturity until the time of soil sampling results in much less K recycling to the soil than normal, and consequently lower soil-test K levels than with normal fall rainfall.
- While a small soil-test P reduction is possible, it is also less likely.
- Scarce or no rainfall since early September slows down the normal reactions between soil nutrient pools, which often results in lower soil-test K levels. Plants are like pumps taking up P and K from the soil, but the uptake decreases sharply a couple of weeks before the crop reaches physiological maturity. Normal rainfall allows for the replenishment of the available nutrient pools from the less available pools.
- Soil pH values likely will be less than normal (more acidic) with drought, with differences ranging from 0.1 to 0.4 pH units being common. This is because small concentrations of soluble salts normally present in the soil solution are not leached to deeper layers by rainfall, which results in higher hydrogen ion concentration and greater acidity in the topsoil. On the other hand, drought has little effect on the soil buffer pH, which is used to estimate the lime requirement.”
He suggests, if possible, to wait on soil sampling until at least a week after a ‘meaningful’ rain event occurs; he suggests that would be one that wets the profile at least 6”. Since that’s not looking likely, if obtaining soil samples this fall, it’s important to obtain a full soil core when sampling and be aware that the K results will be low, P should be fairly on track, and pH will also be low.
Returning to the Farm Workshop Dec. 9-10 at Holthus Convention Center in York: This is a workshop series for families who are in the transition process of bringing members back to the farm or ranch. The series assists families and agricultural operations with developing financial plans and successful working arrangements to meet their unique needs. It will guide families in developing estate and transition plans, setting personal and professional goals and improving the communication process between family members. The workshop fee is $70 per person. It also includes two follow-up virtual workshops in the evenings on Jan. 12 and Feb. 2. Registration & more info: https://cap.unl.edu/rtf22.
Fire Damage to Fields
Am grateful for reports of few people hurt, many homes saved, and I think most cattle saved too from Sunday’s fires. I really can’t imagine how all that works with that many firefighters, first responders, and farmers showing up with equipment driving blind into smoke/dust/fires and everyone staying safe, but am grateful. With Sunday’s winds and the fire damage throughout the State, have received questions on what to do next in these damaged fields and what to anticipate for soil impacts.
For fields that were harvested with residue burned, we’re recommending to get rye or wheat planted into them to potentially get some cover on these fields. I know it’s dry. We keep hoping for moisture with each of these potential rains forecasted (including this week). But if there’s any chance to get some cover, I’ve seen 1″ tall rye produce up to 3″ roots and watched how that size of rye helped this past spring with the winds and in 2019 in helping hold soil during the floods. Rye can germinate down to 32F soil temperature and wheat can germinate down to 39F. So that’s our recommendation. If you have smaller areas where you can get manure on that has any type of bedding in it, that also could help.
A few calling from Nuckolls Co. have wondered about fire damage to long-term no-till. Fire itself won’t damage no-till from the standpoint of the soil structure built. It will remove residue and the organic matter from the residue, but the fire itself doesn’t impact organic matter. Fire and the resulting ash does impact water infiltration as the ash can clog soil pores. Wind erosion can also ‘seal off’ the soil surface which can reduce water infiltration. Thus another reason why drilling a small grain in hopes of disturbing the ash and getting cover established may help.
Nitrogen and sulfur to a small extent are released to the atmosphere during fire, and nitrogen and other nutrients become more available in the soil due to quick mineralization from the fire. Nutrients from the residue will be contained in the ash which can be lost to wind erosion, but those nutrient losses are fairly minimal overall. To read more on soil impacts, see this resource from Montana State. It has an interesting chart showing the amount of N, P, K in the top 6″ of soil and then compares how much is removed from stover that’s harvested or burned. The numbers for residue removal aren’t exactly the same as what we share for Nebraska, but they’re in line.
Plan on soil testing, may be wiser next spring, to determine nutrient levels in these fields prior to planting. The combination of drought + fire may result in greater nitrogen availability than what one may think.
Fire can often aid grasslands, so would say to let pastures work to recover on their own for now.
I hope all the fields impacted were harvested, but if you have a field that wasn’t, please give me a call and we can talk through that. Ultimately, what we’ve been recommending for fields in this situation in northeast Nebraska has been to harvest the fields as normal and send in grain samples to get a feed value and also quality value. All those fields have been corn fields so far. Dr. Mary Drewnoski has put together information on feeding burned corn that we can share for anyone who needs that.
Wind Damage to Replant Corn Fields
I had been watching different forecasters talking about last weekend for a few weeks. Grateful it wasn’t like they were originally predicting. So last Friday I had popped into fields to see how stalks were holding up. From what I was seeing in the replant corn, I figured a lot of the tops would blow out as plants were quickly losing strength above the ears. Was seeing up to 35% stalk rot (base of plants) in irrigated fields and over 50% in non-irrigated. So far, have seen good shank attachment and ear attachment within the shanks. Grateful for how the ears have held on and the bottoms of plants have held up thus far!
In saying this, it’s honestly a matter of time before these replant corn plants will go down and/or potentially drop ears. I seek to be positive, but I also want to be honest with what I’m seeing. I’m hearing the wind dried corn down compared to last week. Please be checking moistures in your fields. I realize everyone’s situations vary with bins, etc.; it may be wise to keep harvesting a little at a time and drying in between instead of waiting for it to dry in the field this year.
If you’re willing to share your replant corn test weights anonymously, please do so here: https://docs.google.com/forms/d/e/1FAIpQLSfpgVRce5VJ6ytg1S2gZlqBfFAa10qINVhWIkVFSpaFh89-7A/viewform?usp=sf_link.
With each of these red flag days, am grateful for our firefighters, first responders, and all involved helping fight fires; praying for all of them and those who are impacted. Sharing this week on some upcoming November programs and a grain question I received when it was cold last week.
Should low moisture corn be cooled in bins? Will running air remove much more moisture? Dr. Ken Hellevang with NDSU answered the following question. “The temperature of the corn will change many times faster than any moisture content change. We can estimate the cooling time by dividing 150 by the airflow rate. So, if the airflow rate is 1.0 cfm/bu, it will only take about 15 hours to cool the corn. To change the moisture content of all the corn at that airflow rate will take about 40 days. Even at a typical aeration airflow rate of about 0.2 cfm/bu it only takes about 3 days to cool the corn.
Anytime we cool the corn, there will be a minor (fraction of a percent) reduction in moisture. Therefore, with dry corn running the fan at night during higher humidity conditions is beneficial. I would run the fan all day and night for the most rapid cooling and just at night if willing to be controlling the fans.
I encourage farmers to cool the corn whenever outside temperatures are 10-15 degrees cooler than the corn, so they certainly could utilize the cooler air to cool the corn.
With the corn at moisture contents of 13% or less, it will store at the warmer temperatures for a while, so there is not a problem with waiting. They will need to cool the corn for winter storage at some time to limit the potential for moisture migration and wet corn at the top of the bin. This occurs if there is consistently at least a 20 degree difference between outdoor air temperature and the corn temperature.”
2022 Nebraska Ballot Initiatives are explained by Dr. Dave Aiken in this document https://agecon.unl.edu/2022-nebraska-ballot-issues and webinar https://go.unl.edu/n2pw.
Cover Crop Grazing Conference will be held November 1st at the Nebraska Research and Extension Center near Mead (1071 Co. Rd. G). This conference is designed for crop and livestock producers with a trade show, speakers, producer panel, and cover crop field demonstrations. The day begins at 9 a.m. with registration and a trade show with the program running from 10 a.m. to 2:45 p.m. Speakers include Ben Beckman (Rotational/Strip Grazing) and Brad Schick (Grazing of Perennial and Annual Forages). There is a $10 registration fee payable via cash or check at the conference to cover lunch and refreshments. RSVP at: https://enrec.unl.edu/covercropgrazingconference/. If interested in exhibiting in the trade show, please contact Connor Biehler at firstname.lastname@example.org or 402-624-8007.
Nebraska Extension Weed Science School will be held Nov. 9 at the Eastern NE Research and Extension Center near Mead (1071 Co. Rd G). Registration begins at 8:30 a.m. with program from 8:45-2:30 p.m. CCA credits are available. Speakers and topics include: Amit Jhala (Nebraska Weed Management Survey Results); Kevin Bradley with University of Missouri (Future of Weed Management in 2023 and Beyond); Jenny Rees (Herbicide options when interseeding cover crops into corn and soybeans); Nahar Neta with Greeneye Technology (Spot herbicide application technology for weed management in corn and soybean); Bob Klein (Spray quality and carrier rate-how they affect herbicide efficacy and spray drift?); Stevan Knezevic (Soybean response to 2,4-D and dicamba); Sam Wortman (Off target injury of dicamba or 2,4-D in specialty crops). No fee but please RSVP for lunch: go.unl.edu/weedscienceschool.
Central NE Regenerative Ag Conference will be held Nov. 18 at the Tassel Performing Arts Center in Holdrege, NE from 1-4:30 p.m. with Gabe Brown as the featured speaker. Fee is $15 if pre-register by Nov. 14; otherwise the fee is $25. Registration is through Central Community College in Holdrege. Register online or you can call them at 308-995-8133. Just FYI, it gave me a confirmation email saying I registered for “Entrepreneurship”, but the day and time were correct. More information at: https://greencover.com/event/soil-health-and-regenerative-agriculture-conference/.
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.
The sun came up with vapors from frosty plants filling the air as it warmed. I know there’s nothing we can do about the frost, but I appreciate it’s still hard. What we can do is know what to expect next from these replant crops. Lots of information below. A blessing is the warmer predicted temperatures for this week.
Conditions vary due to location, hills/valleys, soil moisture, etc. Temperatures at 31F for a few hours can kill leaves while temperatures at 28F for a few minutes can kill the plant, including the stalk of corn and soybean. Four hours at 24F or lower will freeze the growing point at the top of alfalfa and 26F will kill milo (sorghum). Frost symptoms of water-soaked leaves and/or stems will begin 1-2 days post-frost but it can take as much as 5 days before we see the extent of the damage. One thing I’ve thought about is how we’re blessed with irrigation. I know everyone was tired of irrigating, but many pivots ran before this frost. A higher soil moisture content can allow radiant heat from the soil to potentially keep the canopy warmer than the air temperature outside of the canopy. Hopefully that helps reduce frost impacts.
Corn: If only leaves are killed, the ear will continue to fill because the stalk can continue to move carbohydrates to the ear. If only partial leaves are killed, photosynthesis will continue at a slowed rate. If the stalk dies, yield loss increases. In all these cases, stalk quality will be compromised and with these large ears, be aware of plants going down. Check for stalk rot and harvest timely. Estimated yield losses based on research conducted in 1984 where they used 80 and 105 day hybrids:
- 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)
The kernels will eventually form a black layer when there’s no longer nutrients from the placental cells where the kernel tips are attached to the cob. The pre-mature death results in lower test-weight grain (low 50’s to high 40’s) that can be chaffy. Test weights below 53 lb/bu rapidly reduce storage life. Plan on moving low test-weight corn to market before summer and aerating it frequently before then. Kernels can be smaller than normal, misshapen, and may break easily when handled. Grain moisture content will be greater than 35%. Grain drying rates can range from 0.83 to 1.16% moisture less/day when whole plants die prematurely. Research found it took 4-9 more days of field drying to the 22-30% moisture range when corn was frozen before black layer compared to ‘normal’ maturity.
The outer kernel portion will dry slower than the inside part, thus grain moisture will be deceiving. Plan on grain being 1-2% higher than hand-held grain moisture testers. Also plan to dry frost-killed corn 1-2% lower than 14-15% and cool the grain as quickly as possible.
For those planning to dry corn, Peter Thomison from Ohio State shares, “Dry frost-damaged corn at reduced air temperatures (below 160 °F) and store at 14 percent (or lower) moisture. Dry corn as gently as possible, even if it is tempting to crank it up for higher dryer capacity. Also, use slow cooling methods after gas-fired drying to minimize quality problems. If possible, aerate stored grain to cool it to 20 to 30F for winter storage (in the upper Midwest).”
It’s not recommended to make silage from frost-damaged corn because of the excessive moisture in the plant and lower quality. Low test-weight corn and sorghum can be fed to livestock; more information on that here: https://go.unl.edu/0q8i.
Soybean: A killing freeze for soybean is considered 28F. Temperatures below 32F can injure leaves and stems/pods/seeds are injured at 30F. More leaves present can maintain more radiant heat keeping the canopy warmer. If at least one pod was mature on a soybean stem, the remaining seeds on the stem should mature fairly normally with normal colored beans. If just the leaves were froze, but stems remain intact, the beans should continue to fill. I have seen soybean pods that were green in color during a frost result in both round, green-colored beans, or remain green, lima-shaped beans. The beans will be similar to corn in that hand-held moisture testers will read 1-2% low compared to what they actually are. Depending on the percent of green beans at harvest, one may choose to bin the beans and aerate them to allow a reduction in the greenness and moisture in them over time before marketing.
Milo: If the grain hadn’t reached physiological maturity (usually around 40-45 days after flowering), there can be reduced grain yield and reduced test weight when temperatures reach 28F for around 2 hours. Sorghum plants aren’t normally completely killed by frost until temperatures reach 26F. K-State research found yield reduction to be around 20% when the grain is at hard dough stage. They also found a 6.5-27% reduction in grain weight at hard dough and 27-52% reduction at soft dough.
If grazing sorghum forages, it’s best to keep livestock out of them from the first light frost to full hard frost and allow the tissue to completely dry for 5-7 days post hard freeze to avoid prussic acid poisoning.
Alfalfa: Prior to the frost, several had asked about taking another cutting of alfalfa. We don’t recommend that within 6 weeks of a hard frost (24F for 4 hours). One can take a cutting after a hard frost. One can also take a cutting in mid-October even if a hard frost hasn’t yet occurred. The goal with this final cutting is to limit any new regrowth so the plant spends its energy preparing for winter dormancy. I haven’t checked where we’re at, but there’s also a way to consider this final cutting using GDD. Please let me know if you have questions on that and I can share more.
Crop Update: What beautiful weather! Grateful for the crops that are being harvested! Also, grateful to hear some are blowing out combines after harvest in these heavily infested palmer fields before moving to the next field. That’s the first step in managing palmer for the future. Regarding combine cleanout, Market Journal had a video at: https://youtu.be/UtSAaWtMTS4 and CropWatch had an article at: https://go.unl.edu/skfh if you’d like more information.
Managing heavy palmer fields after harvest: Palmer and waterhemp seed survive for 5-7 years. With each plant producing an average of 500,000 seeds, it only takes a few plants to create a mess.
It’s been encouraging to see the rye and other small grains being drilled in fields; I realize it’s also been hard to irrigate them up after such a long irrigation season. Small grains such as rye, wheat, and oats have been proven to significantly reduce palmer, even in the absence of residual herbicide use compared to a no cover crop control. With the addition of a residual herbicide, there was no difference between using a cover crop and the check treatment. However, the way I look at it, the cover crop was another tool to take some of the pressure off the herbicide from having to do all the work. The main reason for that is because these small grains keep the soil surface covered. Palmer germinates when it senses red light on a bare soil surface, so keeping the soil covered can help reduce early season palmer germination. The small grains are also beneficial at reducing diseases such as white mold and sudden death syndrome.
If one isn’t interested in cover crops but is already using reduced tillage, another plan going forward will be to use a PRE- herbicide with residual followed by POST- with residual and get to canopy closure. Essentially, the strategy there is to keep the seeds from germinating.
For those who plan on disking, the research showed that disking once and not disking again for 3 years resulted in palmer reduction of 80-100% by year 3. However, disking each year allowed the seed to keep coming to the surface where it could germinate (depending on the herbicides and timing used). So, planting a cover crop after disking to cover the soil is one option to help reduce palmer germination in the spring. For those not interested in cover crops, having a strong herbicide program of a PRE- with residual followed by a POST- with residual sooner than you think you may need it, may be a strategy. One can also include cultivation followed by a residual herbicide, depending on canopy closure. The use of tillage, flaming, and electrocution are also being used in organic and some conventional systems.
Finishing Replant Crops: Grateful to be at this point in the season where much of the replant corn is 1/4 milk or further! Hybrids will vary regarding growing degree units (GDUs) to finish. A GDD tracking tool to help is https://mygeohub.org/groups/u2u/purdue_gdd. Regarding irrigation, below is the amount of water needed to finish corn. Most of the beans should be close to done for irrigating.
- Beginning dent needs 5.0” water, around 24 days to maturity, 25-55% yield loss potential.
- ¼ milk needs 3.75” water, about 19 days to maturity, 15-35% yield loss potential.
- ½ milk needs 2.25” water, about 13 days to maturity, 5-10% yield loss potential.
- ¾ milk needs 1.0” water, about 7 days to maturity, around 3% yield loss potential.
We knew replant crops would be a target for insect and disease pressure. It’s hard to see the corn earworm impact crops for such a large area as what they have this replant corn. Even fields that were sprayed once still have ear damage on a good 50% of the plants. The earworm feeding has allowed entry of fungi such as those causing white/pink Fusarium ear mold to varying degrees on the ears. Also seeing some blue-gray Penicillium ear mold and some sprouted kernels. Unfortunately, there wasn’t much we could practically do about it and there’s nothing we can do now till harvest. The presence of mold does not automatically mean the presence of mycotoxins. For harvest, it’ll be important to set combines to blow out any lighter, damaged kernels. Will share more on grain management in storage later.
Stem Borer: Have heard some disappointment about soybean yields which I feel is mostly due to beans being pushed too fast with the weather. Soybean stem borer is also being blamed, but it hasn’t been proven via research to reduce yield unless beans become lodged/break off. To understand why, it’s important to understand corn and soybean physiology. Soybeans are dicots like trees and the xylem and phloem are found in rings towards the outside of the stem instead of the center. So the stem borer hollowing out the soybean center doesn’t affect the soybean vascular bundles, but insects like gall midge working on the outside of the stem can. This differs from monocots like corn where the xylem and phloem are arranged throughout the stem. Thus, I don’t think stem borer is the reason for lower soybean yields that weren’t due to lodging/breaking off this year.
Atrazine Comment Period: I’m blessed to work with both conventional and organic farmers and learn from them on various tools used in their operations to combat pests. For conventional farmers, one tool that’s been available for over 60 years is atrazine, which is used for weed control on over 2/3 of U.S. corn and sorghum acres. In listening to farmers, this latest atrazine comment period has been confusing, because EPA just re-registered atrazine for use in Sept. 2020 and confirmed the decision to use 15 parts per billion (ppb) aquatic level of concern. This level was based on a large amount of peer-reviewed scientific research and documentation which were in consensus that that 15 ppb level of concern was considered safe for aquatic environments.
The confusing part to those who were sharing was ‘why this change if it was recently re-registered?’. In Aug. 2021, EPA reopened the decision in response to a court case and published proposed revisions in 2022 which would lower the aquatic level of concern to 3.4 ppb. Re-opening a previously confirmed decision in such a short time-frame doesn’t typically occur. The proposed 3.4 ppb level of concern also doesn’t agree with the large body of scientific evidence that was reviewed to make the 2020 decision. It calls into question the scientific validity of this proposed ruling.
In the proposed ruling, in order to apply atrazine, mitigation strategies would need adopting by farmers based on land quality. Some of these listed include: No pre-emergence applications; Atrazine application prohibited when soils are saturated; Atrazine application prohibited when rain is forecasted during application or for 48 hours after application; Aerial application prohibited; Application rate reduced to 2.0 lbs of atrazine on sorghum, field corn and sweet corn in a year; Inclusion of a picklist to mitigate runoff and leaching based on factors of the field (soil, crop, slope, weather, etc.) and predicted atrazine contamination in watershed field is located in; and Record-keeping requirements. The docket of EPA’s proposed revisions is available on Regulations.gov.
The public comment period to these proposed revisions ends on October 7, 2022. The public comment period allows for anyone to provide their feedback on the changes to inform the EPA of knowledge gaps, considerations or concerns that the public would like addressed.
The following are some suggestions before making any public comments on any topics one feels strongly about: Define your objectives for the comment at the beginning; Use specific situations to strengthen your points; Include positive and negative feedback; Use precise and respectful language to state your concerns, identified gaps of knowledge, or additional considerations; Avoid grammatical errors and spelling errors; Include scientific data when applicable; Avoid opinions or undocumented observations; Use an active voice, not passive; Include solutions or specific changes to the language of the docket; Read the docket fully before writing a comment; and Avoid wordy sentences or dense text blocks.
National Corn Growers Association has a prewritten template that can be viewed on its website, and for those who wish to submit a comment through the group, see the following site: https://ncga.com/take-action/become-an-advocate/take-action.
Beef Quality Assurance (BQA) and BQA transport training will be held Oct. 5th from 10 a.m.-Noon at the Fairgrounds in Geneva. You can RSVP at https://bqa.unl.edu/training-events.
Crop Insurance Workshop will be held Oct. 19 at the Heartland Event Center in Grand Island. Register at: https://cvent.me/R5qeL3 or 402-472-4923.
Central Nebraska Regenerative Ag Conference featuring Gabe Brown will be held Nov. 18 at the Tassel Performing Arts Center in Holdrege, NE from 1-4:30 p.m. Pre-register at: 308-995-8133.
Dr. Kohl will be at Farmers and Ranchers College in Bruning at the Opera House on Dec. 8th.