Understanding Derecho Damaged Fields

by | Aug 17, 2020 | Educational Articles

By now many people have seen pictures of this bin complex located on the west edge of Luther. It’s about six miles south of Boone, Hwy 30 and our farm place. We have heard of unofficial NWS reports of wind speeds as high as 164 mph, which is equal to a high F5 tornado or a low Category 5 hurricane. The town of Madrid, a few miles to the south has tree and building damage similar to what was seen in Joplin a few years ago. The Zearing area has also been mentioned as being hard hit.

Most corn fields in the areas of extreme wind velocities are 90 to 100% flat as are many deep rooted 30 to 40' pine trees. Most grain bins, both on farm and commercial, made out of steel are either blown away or in shambles. Replacing them at this time is a very expensive and lengthy process, even in a normal year. As we all know the cropping years of 2018, 2019 and 2020 have not been normal. The two earlier years were monsoon city with many locations measuring twice the normal amount of rain and many farm operations unable to get their in-season fieldwork completed on time. Many acres were planted one to two months late, if at all, across the entire cornbelt.

Questions from the field are coming in as to what to expect from the corn plants:

1. Will they stand back up? Once the plant tassel most of the energy is expended on the reproductive processes and filling the grain. Disease control is secondary. Earlier in the season the brace roots will straighten the plants upright.

2. Will grain fill be normal? Don’t expect it to be. Plant species and varieties can be rated as to their LAI, or leaf area index, meaning how often the ground would be covered if all the leaves were cut off and laid on the ground. Corn plants can attribute part of their C1 efficiency to the fact they have lots of sun energy capturing cells called chloroplasts they expose to the sun. The middle and upper versus the lower leaves capture most of the photons from the sun. With the plants collapsed there is much less total leaf area left to capture sunlight. We are likely to see stalk quality decrease as time advances.

3. Will moisture use change for the plants? Remember most parts of the Midwest are still in a drought. The average rainfall gained from the storm in most locations was less than 1”. Nutrients typically move from the soil in three days. Diffusion, mass flow and osmotic pull. Water is vital to all three methods. In recent weeks we have seen the corn plants turn lighter green in color as less water is available to help move nutrients in. The collapsed plants could hold more dew in, which could trim ET, but could also lead to more fungal problems.

4. Is there anything that a grower can do for their crop at this time? With no practical way to apply any product to the crops, no. If drones or drone fleets were available applying a systemic nutrient based disease controlling product might make sense. So basically make preparations for having the proper corn head attachments for harvesting downed corn and line up storage facilities if needed.

Farmers are eternal optimists so when given a break in weather defied all odds, so the northern and eastern sections of the Midwest planted those corn and bean acres long after the normal optimum window had closed. In 2019 the months of September and October turned out warm and sunny, so those late planted acres actually matured and were harvested. Test weights were light, yields were lowered, and the harvest moisture were high as field drydown was very slow as daily GDUs were often non-existent.

We live just north of Ames and I have traveled in a few different directions since the storm blew through. I have had many people ask me questions about what I expect to happen over the next few months to the corn plants in the flattened fields. I am not a seer but can relate what just happened to what we have seen in more localized flattened corn events in the last four decades. Waking up early on Sunday I am following thru on the notion that I needed to pass on my thoughts and what might be expected of the crop.

In the Ag world many people remember the individual years by: whether it rained or not; whether there were unusual or heavy insect problems; how the yields turned out; if planting and harvest occurred earlier or later than normal; if there were major cropping problems such as emergence, weed control or products such as Dicamba drift or Scepter carryover; or an abnormal weather event.

I remember 1987 in that rain was scarce in Iowa and fractions of the normal amount would arrive just before the crop was lost. Yields were decent, considering how dry the entire season had been. There was a big windstorm in mid-July east of Carroll that blew the corn down just after pollination. The rest of the season was dry and quite hot and there were not many days with a light breeze. The horizontal corn plants were short of moisture and unable to pull in enough moisture to respire at the normal rate to remain cool. Air movement thru the collapsed plants was minimal and leaf temps were high. Plant tissue scalded as a result. A DeKalb test plot was along that route and I help harvest it. Yields from those collapsed fields varied a bit by variety with overall yields being 40 to 50% of normal.

In comparison there was a big wind west of Marshalltown in 2002, maybe 1992, where the corn was flattened in a fairly large swath after pollination again. The weather the rests of the growing season remained cooler than normal, light breezes occurred on most days, and rainfall events were adequate without much mud. Harvest of those flat fields was slow and most had to be done in one direction, but final yields closely matched those of the non- affected fields.

So weather and environmental conditions thru the rest of August, September and early October will be crucial to determining how the plants fare. We now know that the path of the storm was roughly 770 miles long and about 100 miles wide, running from eastern Nebraska and South Dakota, thru Iowa, Illinois, Indiana and into Ohio. It did flare off to the north delivering strong winds into Wisconsin and Michigan. In vising with other crops people since then and at the local field days it sounds like in the lesser affected fields along and just south of Hwy 20 there were differences in degree of damage based on: varietal family and root growth properties; corn on corn vs following beans; light to moderate CRW populations vs none; deep till the previous fall vs compacted root systems; having a smear layer from a tillage pass the restricted rooting depth; UAN used instead of 82% thinking that the ammonia burned off a portion of the roots reducing their anchoring ability.

In the areas with the strongest winds where metal power poles and 12” hard maple trees snapped off, the corn plants didn’t stand a chance. We do see a difference in that a % of the plants just tipped over if enough rain arrived to soften the ground. In others the plants snapped at ground level. In still others there is a sizeable % that green snapped below the ear. Those planted that got tipped over but are not horizontal to the ground, and still have a functioning root system have the greatest chance of producing an acceptable yield. Plants that are still attached to the ground, but got pinched will have a difficult time moving enough water to the leaves and photosynthates to the developing grain.

The quality of the grain has to be questioned. When you were a kid chucking ears of corn at each other in ear corn fights on the corn piles, getting hit with one hurt. When the plants with large ears attached were getting slammed around last week, most kernels were still in the milk or dough stage and susceptible to bruising. I saw the bruised kernels already beginning to develop mold problems a few days after the storm. Any insurance inspector should be made aware of this problem as it will affect yield and storage life.

As to harvesting the corn this fall, from what I have seen and been told by growers who have experience combining after a big wind or a tornado, there will be challenges. If there is steel or debris strewn through the fields, there may have to be a person riding on the platform ready to hop down and move the debris out of the way. Any piece of steel may have wood with nails in it. They can cause numerous time delaying flats. The newer poly heads allow the plants to flow better thru, up, and over the snouts than the older steel ones, but not as good as with the Drago and Capella heads where the paddles on the gathering chains grab deeper into the foliage. Whether conditions are muddy or dusty there will be problems running the snouts on the ground in attempting to pull the plants thru the head. Figure on having the bearings wear much more than normal. Harvesting in only one direction will be mandatory in many fields, slowing down your harvest pace. Not doing it may leave 20 to 40 Bu/A in the field.

Back in the 1970s in areas of the SW part of the cornbelt where Southwestern Corn Borer were bad, the 1.5” long larvae would girdle the corn plants just above ground level, detaching the plant from the roots. There were corn heads made down in Dimmit, TX that had gathering chains up and over every snout that could manage these detached plants. I am not able to find any reference to them in recent years. Corn reels will definitely be needed by more corn growers this fall.

The insurance adjustors are slow in getting to many clients. They typically work and adjust the fields on the fringe areas first and then move into the worst areas last, as having people hear of 100% loss early is not something they want to have happen. But if I have a choice between harvesting each field that is flat, or taking a 100% loss, and my bins are gone or inoperable and there is no commercial grain storage available, then not harvesting may be the best option.

Storing any grain in the large poly bags is an option. It will still have to be dried or at storable moistures to go into them. An elevated or slightly sloping site will have to be prepared for the large bags. Electric fencing or tapes will have to be in place to keep out burrowing raccoons. Equipment is needed to both load and unload the grain. They are not meant to be long term structures and any grain will have to be moved once the temps rise above freezing. Having a seasoned person with experience to guide you in understanding and managing the bags and equipment is important. Two such individuals are Karl G from Macomb, ILL at 309-456-3887 or Kevin M from Stacyville, IA at 641-710-2309.

In parts of eastern Iowa where Fusarium levels in the soil are high users of the large bags have had problems with molding grain forming in the bags. This has been a problem for those attempting to feed the grain or DDGs produced from the grain due the high levels of mycotoxins. The Fusarium levels are often much higher where Roundup use has been constant as the normal populations of Pseudomonas fl. Have been exterminated. Any grain fed out of those bags later in the springs should be tested for these toxins if fed to reproducing animals or those extremely sensitive to moldy grain.

It will be difficult to deal with all the problems this storm has caused. Was it a Nature made storm or was it nudged up in ferocity with energy from some external source? This is still being debated. Gaining so much strength from a smaller sized storm between Omaha and Carroll to a monster from Jefferson, IA and points east is amazing. It may mean that all bins should be strengthened with deep anchored steel cable that wrap around and over it. That has been proposed. The size of this storm was huge in the Midwest with wind speeds not seen by any local inhabitants we know of. Our consulting climatologist, who is typically correct in his predictions, has recommended these ideas be implemented.

The observation has also been made that many seed companies had their seed fields in the areas that were hit hard. We seem to be noticing that the husks were ripped away from the ears. Will that seed be suitable for planting next spring? Stay abreast of this topic as the people managing their seed quality will be called to pass judgement on this issue.

Having your insurance adjustor out and making their determination should help you immensely. Be sure you inform him of any ear molds that you have documented by pulling the husks back and looking at multiple ears for evidence of bruising. Be aware that having less air movement thru the canopy will increase the incidence and severity of leaf and ear molds, which may not be apparent yet. Bring this up and have the person explain why it won’t happen rather than have to explain why it might. This might be out of his league, so the more you understand it and can explain the causal relationship the more you can explain your position. Think about how weather parameters and plant conditions can deteriorate in a wet late fall and harvest losses can be more severe due to this storm damage.

As most of you know running a corn head lower than normal will increase the amount of dirt that will be pulled in. Guys who worked with the twin row 20 inch corn a few years ago found the bearing were needing to be replaced much sooner than normal. Having a corn reel in place and possibly the ‘rolly cones’ on the outside snouts to move hanging plants up to the cross auger will be important in handling the downed stalks.

As to what to exp ect from soybean plants. They would have been crunched down but appear to be unharmed. Extremely tall plants are now tangled up but still harvestable. Rain is still needed to fill the pods and nutrient availability is lowered due to the dry soils.

I hope this article provides some useful facts and information that you can use. Be safe as you proceed with your tasks.

Bob Streit bastreit@gmail.com