The week of May 4 saw a bustling of field activity across the state. Planting is winding down in many areas across the state, and the farthest along corn is between V2 to V3 and the farthest along soybeans are VC. Stand concerns due to soil crusting and anhydrous ammonia burn emerged this last week, particuarlly in parts of central and NC Iowa. As well as did concerns for weed control either due to weeds coming through PRE herbicides already applied or lack of moisture to activate PREs recently applied or that are going on now. ISU Extension and Outreach field agronomists share more specific updates about what is happening in the regions they cover below.
Gentry Sorenson (Region 2):
“We had a full week without rain in region 2 allowing for rapid planting progress and fieldwork operations. Corn from early plantings in April emerged last Monday. I would estimate greater than 90% of corn planted and 90% or more of soybeans are planted. Some farmers started planting last Monday in wetter areas affected by more rainfall. Sprayers were actively applying pre-herbicides and liquid nitrogen working ahead of planters. Moth flights for black cutworm and true armyworm have slowed over last week. Check out the moth trapping network update 4 for more information and predicted cutting dates in this ICM News. Phone calls consisted of questions about herbicide applications and questions on pastures, although most questions were about weed control in corn and soybean fields.”
Angie Rieck-Hinz (Region 3):
Cerro Gordo, Franklin, Hamilton, Hardin, Humboldt, Webster, Worth, Wright counties
“Excellent weather the week of May 5 through 12 provided a much-needed opportunity to return to field operations and planting. The USDA-NASS Crop Progress and Condition report for Iowa on Monday, May 12 showed corn planting at 81% and 70% complete for the NC and Central Crop Reporting Districts respectively, and soybean planting at 56% and 68% respectively for the NC and Central Crop Reporting Districts. In some places, crop emergence is struggling due to crusty soils as a result of pounding or excessive (5+ inches) rain the week after Easter. Rotary hoes have been tasked into work and some people are replanting or currently weighing options to replant. Remember replant decisions are not just about stand counts, so take time to assess gaps and reasons why stand loss is occurring. From the majority of what I have seen, soil crusting is the primary culprit for stand issues. However, I did spend time in a field where multiple issues were in play and combining to reduce stand, including crusting, anhydrous ammonia burn (see photo), and uneven down force on the planter. The uneven downforce caused the outside rows to be planted much shallower than the rest of the rows. The shallow seedlings experienced imbibitional chilling and caused germination issues, leading to stand loss. In terms of weed control, there are several issues happening. Pre-emerge herbicide that were applied prior to our first planting window were either worked too deep, or the rain moved them out of the germination zone for weed seedlings, so there are many fields with waterhemp (and other weeds) coming through the pre-emerge herbicides. Now, we face the opposite problem with the dry weather. We need rain to activate the pre-emerge herbicides that were applied last week. And topping off the trifecta of herbicide issues is the fenceline spraying and burn-down that is currently happening with low humidity. Under low humidity conditions, weeds tend to “harden off” and absorption of herbicide is compromised, which in turn can compromise control. Consider making your post-applications earlier than usual, or consider a two-pass post application. I have found alfalfa weevil adults and larvae in the same alfalfa fields. So far, nothing has met a threshold for treatment but continue to scout those alfalfa fields. A final reminder that we have had significant black cutworm moth and true armyworm moth flights so scout for these pests as well.”
Terry Basol (Region 4):
Benton, Black Hawk, Bremer, Butler, Chickasaw, Floyd, Grundy, Howard, Mitchell counties
“This past week has been very progressive in regard to spring planting operations for both corn and soybeans here in NC – NE Iowa, as farmers have been able to cover a lot of acres due to dry weather conditions. By the end of the week, if our weather continues to be favorable, many farmers will have corn planting completed and soybeans very near to that. For the early planted acres, corn is emerging and ranges from VE toV1, whereas soybeans are primarily in the VE stage. Continue to scout the corn and soybeans acres that are emerging for stand evaluations. With the warm temperatures the past couple of weeks, also be on the lookout for germinating weeds, and begin to evaluate species and where they occur throughout the field, potential pressure, weed height, and timing of the first post emerge application. According to the USDA-NASS Crop Progress Report, as of May 11, 81 and 56% of the acres have been planted to corn in NC and NE Iowa, respectively. For soybeans, 56 and 48% of the acres have been planted in NC and NE Iowa, respectively. For Oats, 97% of the acres have been seeded here in NC and NE Iowa. Warm temperatures have accelerated the development of alfalfa this past week. Last week the stand here at the Northeast Iowa Research Farm (NERF) averaged 16 inches in height without any visible buds (RFV of 237). This morning the stand has increased to a height of 25 inches and is in the bud stage (one or more nodes with visible buds, but without flowers), with an RFV of 176 using the PEAQ method. It was a dry week last week with no measurable amounts of precipitation received here at the Northeast Iowa Research Farm.”
Josh Michel (Region 5):
Allamakee, Buchanan, Clayton, Delaware, Dubuque, Fayette, Jones, Linn, Winneshiek counties
“A week of dry weather allowed field operations and planting to get back on track after a three-week rain delay in some areas. Nearly 100% of the oats have been planted, with an estimated 60% emerged. An estimated 60% of the corn has been planted, while soybeans are at 50%. Some of the early planted corn has reached V1-V2, while the earliest planted soybeans are at VE-VC. Soil crusting has been a concern for some of these early planted fields. As a result, I’ve seen a few harrows being pulled out of retirement. Alfalfa fields have been growing rapidly and generally look pretty good. Some producers may begin first crop harvest as the weather allows. There’s been some growing concerns about alfalfa weevil feeding. I haven’t seen any significant feeding yet, and many producers will likely manage this concern by harvesting their first crop within the next couple weeks. Pastures continue to green up and are looking good as well. The majority of other field calls I’ve received over the past week have centered around cover crop termination, herbicide programs, and weed identification and management.”
Meaghan Anderson (Region 7):
Boone, Dallas, Jasper, Madison, Marshall, Polk, Story, Tama, Warren counties
“Central Iowa received a surprise rain last Wednesday, but the heat and overall dry conditions have left us all feeling like we could use a drink. The forecast has a few small chances of rainfall that I hope come to pass and the NOAA climate outlooks are leaning cooler and wetter than average toward the end of May. Planting is wrapping up across this area and crops planted last week are already starting to emerge due to the heat. The largest corn I’ve seen is nearly V3 and the largest soybeans are about VC stage. Crops look good overall, though some hybrids and planting dates have had issues with leafing out underground due to the extended cool and wet we had in April. I’ve seen some insect activity in a few fields, as well as some anhydrous burn and problems that resulted from planting into wet soil conditions. Keep scouting fields as they emerge, watch for black cutworm activity in the next couple weeks, and make sure crop stands are as you expect. Most calls over the last week were about weed identification, replant decisions, soil crusting, and herbicide application decisions given the dry weather.”
Rebecca Vittetoe (Region 8):
Iowa, Jefferson, Keokuk, Poweshiek, Washington, Johnson counties
“With a few very isolated, spotty showers last week, the drier conditions allowed for plenty of field activity to take place. We are down to the last 10% or less of the corn and soybeans to be planted. Emerged corn ranges from VE to V3, and emerged soybeans from VE to VC. As you assess stands, check for weed pressure. I’ve noted waterhemp, lambsquarter, velvetleaf, and foxtails coming through PRE herbicides in fields. Also stay alert for true armyworm or black cutworm activity. I've seen some feeding on corn plants that appears to be from a black cutworm larave, but I wasn't able to find the culprit. I've also had a handful reports of bronzed cutworms in the last week most so near homes or building sides. These can be an issue in gardens and lawns rather than in crop fields. On the forage side, some alfalfa fields have already been mowed for first cutting, and I expect to see more in the next week. Using the PEAQ method, an alfalfa field near Washington had an average height of 33 inches at the bud stage, placing the RFV at 145. I’ve noticed a little more alfalfa weevil larvae pressure in the last week –continue to scout your fields for this pest. Pastures are looking good. Common questions this last week focused on weed ID, stand assessments, and insect activity.”
Virgil Schmitt (Region 9):
Cedar, Clinton, Des Moines, Henry, Jackson, Lee, Louisa, Muscatine, Scott counties
“Most of the area I cover received no rainfall during the last week. Where it did rain, it was very minimal. In general, field work progressed well last week. I would guess that about 90% of the corn is planted. The most progressed corn I have seen is at V3. I have seen a few of the earliest planted fields torn up and replanted. I would guess that 75+% of the soybeans are planted. I have not seen any emerged soybeans, but I am sure there are some. Hay and pastures look good and the harvest of first cutting hay began last week. Calls last week mostly centered around weed management. There is concern about herbicides applied with no rain following resulting in diminished weed control.”
Aaron Saeugling (Region 10):
Adair, Adams, Cass, Clarke, Decatur, East Pottawattamie, Fremont, Mills, Montgomery, Page, Ringgold, Taylor, Union, West Pottawattamie counties
“Lots of progress has been made in the last week. Much of the corn is planted and the early planted corn is V2 to V3. Some areas had crusting issues, and as a result a few fields are being replanted. Soybean planting is not far behind corn planting, and it will be caught up by the end of the week except for where soybeans will be planted following rye fields that will be chopped. Some soybeans also had emergence issues, which may result in replanting in cases. Overall, crops look good for this time of year, and rain would be welcome for most corn and soybean fields. First cutting hay is being cut as well as small grains for silage. Early post emerge applications will start this week on the bigger corn.”
Logan McCrea (Region 11):
Appanoose, Davis, Lucas, Mahaska, Marion, Monroe, Van Buren, Wapello, Wayne counties
“This past week has been a blur in SC Iowa, with a little bit of everything occurring in fields due to the warm temperatures and little precipitation. Some alfalfa first cutting is beginning to occur, with other fields being not too far behind. The PEAQ method is a great tool to use for optimizing first cutting in your alfalfa fields. Corn and soybean planting continued along at blistering paces and is making its way to the finish line. Early emerged corn and soybeans look good, with lots of early planted corn being around V2-V3 and most soybeans hovering around VC. Be on the lookout for black cutworm cutting over the next week or two as lots of the corn and soybeans are emerging and can be vulnerable to the larvae through the crop's young growth stages.”
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- Field Agronomist in EC/SE Iowa