Iowa crop update for June 7 to June 12, 2016

June 13, 2016 4:28 PM
Blog Post

Iowa Crop Progress Summary
The USDA Weekly Crop Progress Report showed that Iowa's corn crop is 99% emerged and has a good/excellent rating of 80% for the week ending June 12. The agency reported 91% of Iowa soybeans have emerged, 10% ahead of the 5-year-average. The good/excellent rating for Iowa soybeans are 81%, compared to the U.S. good/excellent rating of 74%. Sulfur deficiency and herbicide injury are two issues seen throughout the state over the past week, as side-dress nitrogen applications and postemergence herbicide applications continue. Read on for more information about your region's crop progress and field conditions from Iowa State University Extension and Outreach field agronomists.

Joel DeJong (Region 1): We had a dry, hot week in the northwest corner of Iowa this past week. Limited rain fell in the northwest corner Friday night, but the remainder stayed dry.  A lot of soybeans were planted on the Missouri River bottom during the past week, finally. Growth of corn was tremendous, but some showed problems from inhibited root systems (compaction, wet panting, etc.) during the three days with temperatures in the mid-90’s. Over the past week, I observed instances of herbicide injury in some fields, but it looks like most will recover OK. Stalk borer migration has begun, so check field borders in fields with corn hybrids that don’t have protection from Bt traits effective on stalk borers.

Paul Kassel (Region 2): Corn is stage V4-V8 in my region of northwest Iowa. The April 15-17 planting is V8 to V9 and is almost shading the rows in 30-inch rows. The late planted/replant corn is also looking good and is in the V4 stage. The soybean crop is also advancing. We are seeing the soybean crop in the VE-V2 stage. Farmers have been busy with side-dress nitrogen applications and post emergence herbicide applications.  

Terry Basol (Region 4):
Warm temperatures last week helped spur the development of both the corn and soybeans in northeast Iowa. Corn is at the V5-V6 stage, with some of the early planted fields starting to show canopy closure over the row. Soybeans are in the V2-V3 growth stage with most of the fields having the first trifoliate leaves fully expanded. Hay harvest was in full swing, and most of the first cutting harvest has been completed. There was a lot of field operations happening last week that included side-dress nitrogen applications for the corn and postemergence herbicide applications. Rainfall was abundant for the latter part of the week, as we received 4.02 inches of rain, with the greater share of it occurring the 10th and 11th of June (2.34” and 1.45” for the 10th and 11th, respectively). I live in Waverly and dumped out 4.8 inches of rain from my rain gauge Saturday morning.

Brian Lang (Region 5): The first 5 weeks of corn growth is often referred to as the “ugly phase.” Corn fields often look uniform through V3 stage. If “ugly phase” corn had any problems with early root growth and/or premature rot of the mesocotyl from factors such as soil borne disease, soil insects, herbicide injury, fertilizer burn, etc., then unevenness will be increasingly noticeable as fields advance to V6 stage. Scout these uneven areas in the field to sort out why some the of the corn suffered significantly more stress in order to adjust management in the future. 

West Central and Southwest
Michael Witt (Region 11):
Corn is around the V4-V7 stage, on average, for west central Iowa. The crops are generally healthy with little nitrogen or other nutrient issues. Soybeans are ranging in maturity from V2-V4. Ninety-eight percent of planted beans have emerged across the area. Plants of all crops have been growing significantly this past week with the warm weather. There is adequate mid-to deep subsoil moisture, but crops could still use some moisture in the top layer. There is some plant curling and heat stress due to the abnormally hot temperatures of the last week. Herbicide spray damage has started across the area. This is mostly due to improper calibration of sprayer equipment, poor cleaning of equipment and tanks, improper mixing with surfactants and chemicals, or wrong chemical application. These issues have been mainly in corn with soybean spraying still going slowly across the area. Striped rust has been discovered in wheat crops in Iowa and across the Midwest. With rain forecasted early in the week, then a return to warm and dry conditions, crops and weeds will grow rapidly; proper crop scouting is essential for fields.

Clarke McGrath: In southwest and west central Iowa, corn spraying is about wrapped up. For fields yet to go, just take a minute to double check corn stage/size and compare to herbicide labels. We don’t want anyone to run into herbicide injury, as this corn is really growing quickly and might be pushing the upper limits of some product labels. Soybean spraying is getting started. Be sure to check weed sizes vs. herbicide rates so you can maximize herbicide effectiveness. I am getting calls on some pretty sizeable weeds in fields, especially ragweed and waterhemp.

Mark Johnson (Region 7): I had two calls last week wondering if what they saw was sulfur deficiency. One was eroded side hills on two fields, and the other was low organic matter areas of two fields. In both cases, there was no recent history of manure. With the side hill fields, the soil test levels for potassium were also low. They both were indeed sulfur deficiency and are being treated.

I had 2.5 inches of rain Saturday morning and some other areas in my area were similar, with parts of Warren County getting nearly double that, and some parts of my area getting far less. The photo below of rolled corn in Dallas County shows the need for rain that’s in the forecast for Monday night (June 13) and Tuesday (June 14).

Photo by Mark Johnson

East Central, Southeast, South Central
Rebecca Vittetoe (Region 8): In south central Iowa, the crops have really grown this past week. You are seeing more unevenness show up in fields, especially corn. This is likely attributed to the stage the crop is at, stresses from earlier in the season, and the warmer and dryer weather we’ve experienced. From a pest perspective, not much insect activity, but I have seen a field with northern corn leaf blight.

Meaghan Anderson (Region 9): Corn is mostly in the V6-V8 stage and soybeans in the V1-V4 stage in my area of east central Iowa. Crops look good for the most part, but soil texture differences are really showing in some fields with corn color and height differences. My more northern counties received between 0.5 and 1.2 inches of rain this last week, but more southern counties could really use some rain with the hot temperatures we’re getting. I’ve been busy with field calls lately – starter fertilizer/anhydrous ammonia root burn and herbicide injury are the two most common things I’m seeing, as corn that had better roots really outpaced their injured neighbors.

Virgil Schmitt (Region 10): Rainfall for the last week varied from zero in the south to about 0.5 inches in the northern part of east central Iowa. South of I-80, lawns are starting to go dormant. Oats are headed, and alfalfa regrowth is looking good. Corn is at the V7-V9 growth stage, and soybean is at the V2-V4 growth stage. Herbicide injury Groups 2, Group 4, Group 27, bronzing from surfactants late in the week. Grasshopper nymphs are present. Issues in east central and southeast Iowa over the past week include sulfur deficiencies, May 9 planting poor stand, and Liberty drift.

Find your local ISU Extension and Outreach field agronomist here!