Crop Update: What a blessing to have rain this past week! Grateful for how it provided much needed moisture into the top two feet in many cases. Updated soil moisture status will be at http://jenreesources.com. Some in our area and in other parts of the State received wind, hail damage, and flooding to crops. This week’s CropWatch at http://cropwatch.unl.edu shares information for those situations. A few summarizing points: for those with greensnap or with severe hail damage, you may wonder what potential yield may be based on your planting date and current plant stand. The following chart from Iowa State University and explanation of how to understand it may be helpful: https://crops.extension.iastate.edu/cropnews/2009/05/assessing-corn-stands-replanting.
For those with flooding, corn in the V7-10 leaf stage can survive for about 7-10 days in flooded water. Temperatures above 86F can result in greater stress on those plants than if the temps remain cooler than that during that time. Another consideration for the future, it’s not uncommon to find a disease called ‘crazy top’ of corn when the tassels begin to emerge. We’ve seen this the past several years where creeks or areas along waterways or field edges were ponded. There’s nothing you can do to prevent this.
For those with hail damage, damage from V7-10 leaf corn can result in a number of situations depending on the severity of hail. Minimal yield loss is assumed for leaf damage in crop insurance charts. Final plant stands will be important which will account for broken off plants that don’t recover. Stem bruising also isn’t factored in. For corn, bacterial diseases tend to be my larger concern at these growth stages. Bacterial top rot is one in which the plant dies from the top down and has a strong odor to it and creates a soft, slimy mess. Goss’ wilt is another concern-particularly systemic Goss’ wilt. You can check for this if you have a dying plant that doesn’t have a soft rot by taking a
cross section of the stem and looking for discoloration of the vascular bundles. You can also send plants like this to the Plant and Pest Diagnostic Lab in Lincoln for confirmation.
Regarding fungicide use on hail damaged corn, Iowa State and the University of Illinois did studies finding similar results. Both found no statistical difference in applying a fungicide vs. the untreated check in spite of small numerical differences. Regarding timing, the Iowa State study simulated hail damage at tassel and applied fungicide an average of 3 days and 8 days post-hail. There were no statistical differences on yield of the timing of the applications either. They did find statistically less fungal diseases in the hail-damaged plots vs. the non-hail damaged plots and speculated it was due to more air flow and less leaf area available for disease to occur. I have observed that fungicide can help with stalk strength and maintaining whatever green tissue remains when we had the 2013 hail storm in Clay County at brown-silk to blister corn. But this early, it’s hard to justify a fungicide application based on the data that’s available. If you’re interested in testing this for yourself, the following is an on-farm research Fungicide Protocol for Hailed Corn and Soybean.
For hail damage on soybean, many of the beans are at flowering or approaching flowering. Again, stem bruising isn’t counted in crop insurance assessments. I haven’t really observed bacterial or other disease issues necessarily from stem bruising in soybean. What tends to be more of an issue is those plants hardening off and becoming brittle to walk through. For soybeans, the blessing is that often new buds form and you will see increased branching which can help with canopy closure…it just can hurt right now when soybeans were already near canopy and we’re trying to reduce additional inputs for weed control. Things to consider are that pods may be closer to the ground from this increased branching and you may need to harvest earlier to help with getting beans that become brittle before snapping off in wind storms. I leave plant stands of near 60,000 plants/acre based on our soybean pop studies that received hail damage. If you want to prove any replanting differences to yourself, you may wish to consider the following Soybean Replant Protocol. We’d recommend waiting on herbicide apps till some new growth occurs, which is difficult when I’ve watched palmer essentially be not affected by hail and put on two new leaves within a few days in the past. Last year we started making herbicide apps 5-7 days post-hail. Additional hail resources are at a new resource called ‘Hail Know’ at: https://cropwatch.unl.edu/hailknow. There’s a lot of info I haven’t transferred to this site yet…but you can view photos and comments on hail recovery at numerous growth stages over time at my blog under the ‘Storm Damage’ category: https://jenreesources.com/category/storm-damage-2/.
Last week I shared the following video regarding determining timing of off-target dicamba movement to soybean: https://youtu.be/rQid7-vX-TU. Sharing again with an increase in the number of fields that were experiencing cupped symptoms last week.
May 23: Corn is looking good for the most part with few major concerns yet. Some have commented on the yellow-looking corn. This is most likely due to cool, wet soils rather than any nutrient issues. There may be field-specific issues such as saturated soils, compaction, and some herbicides that can cause this yellowing too. Also had a call on cutworms in seed corn but not widespread calls on this yet. Extension Educators have set up light traps for tracking cutworm moths and you can find that information here: http://go.unl.edu/rhhe. Cutworms will cause the most damage the first 7 days after corn emergence so scouting is important. The York County Corn Grower Plot was planted on April 24th with the corn currently at 2 leaf stage. Special thanks to Ron, Ray, and Brad Makovicka for hosting and the work put into this plot each year!
May 1: It never ceases to amaze me how quickly planting occurs each year! Corn planted the week of April 10th has emerged and for those fields that received hail from last week’s storms, I’m hoping we don’t see disease issues later on. Also of note, some have asked me about the CropWatch soil temperatures as they are higher than what some of you have been measuring in your fields before planting. The CropWatch soil temps at http://cropwatch.unl.edu/cropwatchsoiltemperature are averages of 24 hours under bare soil which may be different than the residue conditions in your fields and is an average of the entire day vs. one point in time. This may help explain some of the differences.
Many stands of alfalfa are lush green with over a foot of growth at this point. I looked at some alfalfa in Clay County that got dinged by cold temperatures in areas of the field and stopped growing. At this time I’m also finding quite a few aphids and a few alfalfa weevils. A disease common this time of year called spring black stem can be observed in nearly all alfalfa fields right now in the lower canopies. This disease consists of small black lesions on the leaves which eventually cause the leaves to turn yellow and drop. Normally this disappears with later cuttings as humidity and rainfall are typically high during the first cutting and can be managed with cutting the alfalfa. One option to consider according to Dr. Bruce Anderson, our Extension Forage Specialist, is to consider cutting alfalfa before bloom. He shares that weather can cause long delays and alfalfa doesn’t bloom very aggressively during spring. Bruce felt there were advantages to cutting alfalfa when it is 15-20” tall before bloom during first cutting including: weather compared to later spring, spread out alfalfa harvest if you consider cutting one field earlier, reduction in insect and disease problems by early harvest, and high feed value. It also potentially allows the second cutting to be ready before the summer heat which can lower forage quality. Disadvantages include lower yield from cutting early which could be made up in later harvest, regrowth may be slower if cut early, and the need to allow for longer recovery after first or second cutting to maintain long-term stands. So, harvesting before bloom may be something you wish to test in one of your fields this year and consider how this works for you, especially if you did have some frost damage or are having insect/disease issues in your alfalfa right now.
Before the bus started moving we were working on plant identification for a client. Then we learned about the status of Emerald Ash Borer among other pests at the Douglas-Sarpy County Extension Office. By the end of the presentation we were considering getting a meat thermometer and recordable Hallmark card! (will explain later).
Along the way, John Wilson provided an update regarding the flood recovery efforts from the 2011 flood. He mentioned at Gavins Point Dam, the lake would have drained every 25 hrs. when releases were occurring for the flood. He was involved with an effort in putting together a webinar that involved 25-30 agencies and 14 speakers from 5 states. During the recovery there were 2″ to 25′ drifts of sand in fields. One piece of ground that was reclaimed cost $125-150K and needed 7 excavators for a month. One 300 acre piece of ground that wasn’t reclaimed was going to cost $10,000/ac. to reclaim it.
John Hay provided an update regarding wind energy. He pointed out the different types of towers along the way as we passed several wind farms. Facts included: a 1.5Megawatt wind turbine can run 1000 homes each and the gear box is turning 2000:1 compared to the blades. Iowa is #1 in percent of electricity produced from wind power (20%) and it costs $3-6 million each to install a wind turbine (essentially double the cost of how many megawatts). The life span of a turbine is 20 years with a maintenance cost about $0.05/kwh. When considering efficiency, wind turbines are 40-50% efficient vs. coal power (35%), nuclear (35%), cars (25%); so they’re more efficient at converting free energy into electricity but they are less cost efficient than those other energy sources. Windfarms also typically pay for themselves in 5-10 years.
Our first stop was at Hawkeye Breeders where we saw their semen storage facility that essentially had enough semen to fertilize every cow in the U.S. They ship all over the world and their primary customer is the dairy industry. We also toured their semen collection facility and got the coolest pen from there.
From there we stopped at Blue River Organic Seeds and were surprised to learn that all their organic seed research is done conventionally. They provide organic seed for corn, alfalfa, soybean, and various forages and are looking for more growers. We also learned about PuraMaize which was developed by Dr. Tom Hoegemeyer to essentially block pollen from outside sources to maintain purity.
That night we had supper with faculty from Iowa State University talking about programming efforts there, including their manure programming, ag economics, and Roger Elmore spoke of the corn programming there. But before that, a few of us took advantage of the 45 min. of time to get a few geocaches in the area 🙂
Memorial Day storms hit us again this year, this time with the EF2 tornado in Edgar. I checked NE Rain, and for the month, Clay County received between 5.9-9.7″ of rain with nearly 3/4 of that coming in the last 6 days !
Even with the saturated soils and localized flooding, there is still potential for drought. It was this way last year at the end of May before the rains shut off in early June.
I’ve received questions regarding potential storm damage to crops. Normally I’ve found that waiting a week helps with determining regrowth and decisions. Overall, we’re fortunate that crops were so small. Much of the corn was V1-V3 and the soybeans were anywhere from not planted to cotyledon stage. The majority of damage occurred where emerged plants were silted over with soil and/or residue, standing in water for periods of time, of left with stems due to high wind and/or hail.
According to Purdue University Agronomist, Bob Nielsen, it takes around 48 hours for oxygen to be completely depleted from saturated soils. Plants that are emerged above the water have a better chance of survival than those below it; however, it’s hard to tell exactly how long plants can survive in those conditions. We also have several areas where plants were standing in water for a few days, the water receded, and now they’re standing in water again. Only time will tell how those plants will fare.
Because the growing point of affected corn plants is below ground, in many situations, plants should recover if the growing point remained healthy. Hopefully only small areas will need to be replanted. For crop insurance decisions and options, please check out the following CropWatch article.
Some emerged soybeans that were at cotyledon stage have been reduced to stems leaving gaps between healthy plants. Soybean plants can compensate for reduced populations; however length of gaps and final stands do need to be assessed for replant decisions. UNL on-farm research has shown less than 1.4-2.0 bu/ac yield difference between planting 90,000 and 180,000 seeds/acre. (See report.) In our research, 90% of the planted stand was achieved at both seeding rates in irrigated 30-inch rows in no-till and ridge-till fields.
Consider what was found in 2006 in one dryland field in Nuckolls County where seeding rates of 100,000, 130,000, and 160,000 seeds/acre were planted. This field was at the cotyledon stage when it was hailed. Some plant stands dropped to 67,000 plants/ac. Yield was 4 bu/ac less than in the 160,000 seed/acre planting that had a final stand of nearly 98,000 plants/ac. The average yield in the field was 40 bu/ac. While this is only one field and one year of research, it is an example of how soybean plants can compensate for reduced populations by branching and how August rains in dryland can still allow reasonable yields to be produced. Based on our on-farm research, leaving dryland stands of at least 65,000 plants/acre and irrigated stands of 90,000 plants/acre is likely a better choice than replanting, in the event that the gaps between plants are not large and are fairly even.
Many of the soybeans worst affected were reduced to stems. Last year we watched as soybeans continued to develop plumules after the hail events and soil crusting in our area. The plumule, which is the seedling stem tip and its undeveloped leaves above the cotyledonary node, may remain, but without the cotyledons to serve as a carbon and nitrogen source, development of new seedlings with small leaflets will be slow. These plants may not become competitive with surrounding plants in terms of pod and seed production. Therefore, when counting seedlings to determine plant stand, count only the seedlings that have at least one cotyledon. You can count seedlings missing cotyledons if they have large unifoliolate leaves that will soon unroll as in this picture.
we will monitor damage early next week to help with replant decisions. Overall, I feel we are fortunate that the crops were so small and crop damage does not appear to be severe other than all the pivots that need to be replaced. We will also need to watch for potential disease damage in weakened plants. For crop insurance decisions and options, please check out the following CropWatch article.
The recent rains have left their impact on fields throughout the county and Nebraska in general. I’ve received several questions this week regarding flooded fields and how to help crops buried beneath piles of residue.
For flooded fields, Bob Nielsen with Purdue University wrote an excellent article to address these concerns. In short, our cooler temperatures will help plants survive better, but plants completely submerged under water in saturated soils for more than 48 hours don’t stand much of a chance for survival. You can read his entire article here.
If there’s one thing I would like to see farmers reconsider, it’s stalk chopping. It seems like every year we deal with heavy rains washing stalks from fields where they pile in certain areas of the fields burying plants, covering roadside ditches or jamming creeks. Talking to my colleagues and to several area farmers, we’ve all considered burning as an option. However, burning may only get the top-most dry material while the material underneath is still wet and won’t burn. Another farmer correctly pointed out that there’s usually so much silt intermingled with the residue that it’s hard to get a good burn anyway.
Keith Glewen, UNL Extension Educator in Saunders Co. suggests you consider harrowing or possibly rotary hoeing the stalks, knowing that the depth of stalks and the period of time which elapses following a heavy rain event are important factors in determining success or failure in managing the unwanted stalks. There’s a short amount of time to get that residue off those plants if there’s no light getting down to them. In some situations in the county, residue is up to 1 ft. deep over the top of plants. Harrowing can help even out the field and emerged seedlings may be damaged, but the growing point for corn is still below ground at this point. For emerged beans, the growing point would be above ground so harrowing wouldn’t be a good option. With the rains again today and forecast for more in the future, I’m not even sure that harrowing is much of an option right now for corn as it will take awhile to get back into the fields. In places where 1 ft. of residue is burying plants and the inability to get to those piles with the wet conditions, I don’t expect much plant survival there.
For now we’ll have to wait and see. In the mean time, evaluate your operation and the need for chopping stalks. If you don’t detach the stalk it won’t move. UNL on-farm research found no yield benefit to shredding vs. not shredding stalks in the research which can be found here.