On-Farm Research Protocols:
Hail and wind damage occurred throughout the area I serve last week. Overall, I’ve been encouraged by the regrowth observed on corn and soybean plants affected by the June 14th storm. We were blessed with warmer weather and sunshine that allowed for regrowth to occur in many situations other than some fields around the Deweese area.
You can look for regrowth on leaves within the whorl of corn plants and on the axillary buds of soybeans. Even what appeared to be soybean ‘sticks’ may show regrowth by now.
The concerns I have for plants affected by these storms is all the stem bruising on both corn and soybeans and the potential for bacterial diseases to affect corn.
For those of you affected by June 16th storms, we recommend to wait a week to assess damage and any decisions. I realize we’re also at a critical stage for replant decisions as we continue later in the season. Ultimately, decisions need to be made on a field by field basis.
- CropWatch Hail Damage Resources
- Resources from storm damage in 2014
- Fungicide Use After Hail or Wind
There’s no good research to Dr. Tamra Jackson-Ziems or my knowledge to support this. Fungicides only control fungal diseases. Bacterial diseases are favored after hail events and we have already seen bacterial leaf streak in the area prior to the storm. From past-years’ experience of prior wind/rain events, we can expect to see more of it in about a week. Fungicides won’t help that disease nor Goss’s wilt which is another we often see come in after hail events.
However, if you’re considering this, I’d like to have several farmers prove it to yourselves with on-farm research this year so we do have data for the future. It’s this simple. All you do is spray fungicide in enough width to complete 2 combine passes. Then skip an area for 2 combine passes. Then treat again and repeat across the field. Fungicide Protocol for Hailed Corn and Soybean. Please let me know if you’re interested in this!
Timing of fungicide app: ISU did a study to simulate hail damaged corn at tassel stage within an average of 3 or 8 days post-hail. They didn’t find the timing to provide any yield effects. They also didn’t find a statistical yield increase (90% confidence level) in fungicide application to hail damaged plants vs those which weren’t hailed although they also reported a numerical increase in 12 of the 20 fields.
Herbicide application: I spoke with Dr. Amit Jhala, Extension Weed Specialist for his thoughts regarding this. He said ultimately herbicides shouldn’t be applied to stressed weeds in order to achieve greatest efficacy. The concern for many including me right now is how well the weeds survived the hail and how quickly they are regrowing compared to the damaged corn and soybeans. This again is a field by field assessment regarding how well your corn and soybean regrowth is occurring and how rapidly your weeds are. I watched one palmer plant in one field after June 14 storm: 1 day post hail and 2 days post hail put on two sets of leaves in that time period. I also took pictures of soybeans reduced to sticks while waterhemp in that field was virtually untouched. I think many are trying to wait 5-7 days post-hail to apply herbicides but there were some fields I was suggesting to apply over the weekend with the recovery already occurring and less damage.
Corn replant: The biggest concerns with corn would be stands, eventual stalk rot/downed corn due to stalk bruising, and bacterial diseases. I’ve essentially watched stands reduced over the course of the growing season after early-season hail storms mostly due to bacterial diseases like Goss’ wilt. It will be important to have your crop insurance adjuster look at the field again prior to harvest. Splitting the stems of damaged plants across the field can help you assess any damage to growing points; they should be white/yellow and firm not brown and soft. Tattered leaves that are wrapped around the whorl should eventually turn brown and break off with the wind. They can sometimes impede new growth from the whorl as well though.
Soybean replant: Soybeans can compensate so greatly for reduced stands. From hail at this stage in the past, we’ve said to leave stands of non-irrigated at 60,000 plants per acre and irrigated at 75,000 plants per acre. Some soybeans reduced to sticks are shooting axillary buds. My biggest concern on soybeans is the stem bruising which isn’t accounted for in hail adjustments. If you want to prove replanting or not to yourself, consider slicing in soybeans next to the old row in strips across your field. Be sure to inoculate the soybeans and be sure to take prior stand counts. Soybean Replant Protocol.
There’s nothing like doing these studies and seeing the results on your own ground or from your peers’ farms. In 2006, I worked with a grower in the Lawrence, NE area on a non-irrigated soybean plant population study where he tested seeding rates of 100K, 130K, and 160K seeds/acre. He received hail at the cotyledon stage and because he was non-irrigated, chose to leave the stand. His actual stand counts were 74.4K, 89.4K, and 97.9K plants/acre respectively for the previous mentioned seeding rates which resulted in yields of 38.6, 40.6, 42.7 bu/ac respectively. Another soybean replant study occurred near Columbus, NE where the grower had an average plant stand of 75,000 plants per acre on June 11th. He chose to replant five strips across the field at a diagonal to the existing rows. The replanted soybeans ended up yielding 1 bu/ac less than the original plant stand. I realize it’s hard to want to do these extra steps for on-farm research, but this is why it’s important; it’s the way to answer these questions for yourself! Please contact one of our team members if you’re interested in on-farm research this year!
This year I was counting my blessings as we made it through May with no tornadoes in Clay County and no Memorial Day storms! Yet history seems to repeat itself on days. Last year, hail went through the counties north of us on June 3. This year, hail hit us on June 3rd….an estimated 30% of Clay County. Please also see the resources listed at the end of this post for more specific information regarding decision-making.
For more information on hail and replant decisions, please see:
On May 6, quite a storm was unleashed in south central Nebraska. Soybeans that had been planted two to three days before the storm seem to have emerged fine, while those planted May 5-6 tend to have uneven emergence and crusting. This is occurring regardless of tillage type, residue cover, etc. Many farmers have been running pivots to help the soybeans break through the ½- to 2-inch crust, often applying an inch of water before they see stand improvements.
The primary question for growers has been “Should I replant?”
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 populations 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. Yield was 4 bu/ac less than in the 160,000 seed/acre planting that had a final stand of nearly 98,000. 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.
UNL research conducted by Dr. Jim Specht, UNL Soybean Physiologist, also has shown that for every day planting is delayed after May 1, there is the potential to lose 1/4 to 5/8 bushel per day. As we near the end of May and early June and consider that late planting yield penalty and the dry soil conditions (particularly in dryland fields), along with the seeding rate results from this UNL on-farm research, we are recommending that growers leave stands in many fields. 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.
We realize that there are some larger gaps in various rows in the field, and while we don’t like to see that, the gaps are disappearing as plants continue to grow and branch out. Keep in mind that a gap in one plant row will be compensated by plants in the adjacent flanking rows. They will form extra branches to take advantage of the sunlight, thus single-row gaps may not be as yield-reducing as you might think — especially in 15-inch row spacings.
We’re also seeing how resilient soybeans are. Some soybeans have been in the ground for two weeks and in many cases, are fairly healthy below the crust. Soybean seedlings emerge by pulling (not pushing) their cotyledons upward. The seedlings rely on the cotyledons as a reserve source of carbohydrate, protein, and lipid to support early seedling development until leaflets open for photosynthesis. When a seedling tries to pull its cotyledons through a crack in the crust, the crack may be too small and the cotyledons may be stripped off.
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 after a soil crusting event, 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 such as the picture on this page.
Recommendation: When deciding whether to replant your field, consider UNL research findings that showed a minimal yield difference between stands of 90,000 and 180,000 seeds/acre. We recommend leaving irrigated soybean plant stands of 90,000 or more and dryland plant stands of 65,000 or more. Uniformity of plant stands is also important, but “patch” planting may be used to deal with local areas of low plant stands.
For more information on reduced soybean planting rates, see the April 20, 2012 CropWatch story, Drop Soybean Seeding Rate and Save $10-$18 per Acre.