Crop Update - September 5 - September 13

As the 2017 growing season winds down, ISU Extension and Outreach field agronomists share how the crops are progressing and finishing out the season in their repressive regions across the state.   

Northwest Iowa

Paul Kassel (Region 2): “Signs of crop maturity are apparent in a large part of my area. Crop maturity is a little further advanced in the counties that were affected more by the drought, which is parts of Buena Vista, Pocahontas and Sac counties. Corn is in the half milk line stage (R5.5) to black layer (R6). Some cornfields are entirely brown in color. Corn silage harvest is mostly complete. Many soybean fields are appearing more yellow in color, and most soybean fields have reached late R6 to early R7 maturity stages in much of the area.”

Ear corn judging at the Clay County Fair. Photo by: Paul Kassel

Northeast Iowa

Terry Bassol (Region 4): “Corn and soybeans here in NE Iowa are showing some moisture stress due to lack of rain events in the past few weeks. According to the Iowa Mesonet there has been 0.18” of precipitation at the ISU NE Iowa Research and Demonstration Farm here at Nashua from August 22 through the time of writing this update. Corn is currently in the mid-dent stage (R5.5 – R5.6), and progression of the milk line is roughly at half to sixty percent. Cooler than normal temperatures have continued, resulting in growing degree day (GDD) accumulation being behind by 184 GDD’s compared to the long-term average for the Nashua location (see map below). Soybeans have started turning color in many of the fields in NE Iowa, in which indicates the transition from the end of the R6 stage to the R7 stage, where one normal pod on the main stem has reached its’ mature pod color.”

Growing degree day departures from normal for the 2017 growing season across the state of Iowa from April 1 through September 12. Source: ISU Mesonet.

Central Iowa:

Mark Johnson (Region 7): “I continue to see spots in almost all fields in my nine counties where it is obvious there are problems. Mostly due to soil changes or soil management prior to or during the planting operation; compaction, sidewall compaction, etc. Corn is nearing physiological maturity (R6), with many fields in mid to late R5 stage. Many fields have at least some areas where the plants have reached premature black layer. Those areas will not gain anymore yield and will likely bring the field average down. Most soybeans are at least at the R5.5 stage and many fields are in stages beyond that. I haven’t observed any at physiological maturity (R8) yet.  It’s not uncommon to see fields with several different stages from one end to the other end.”  

Southwest Iowa

Aaron Saeugling (Region 6): “Corn is in the late dough (R4) to dent (R5) stage. Most silage has been cut at this point. High moisture corn will begin this week in most areas.  We are dry and could use a nice general rain across the area. Crop progress is maturing fast for corn. Soybean harvest has NOT started yet, but it is very close. I expect beans to be going in two weeks or less based on the forecast. We should see a much earlier harvest on soybeans this season than last year. Early maturity soybeans are dropping leaves and turning brown. Forage last cutting hay has been harvested or will be baled in the next week. There has been some discussion around cover crops. We really need a rain for a cover crop seeding to be successful.”  

Southeast and South-central Iowa:

Rebecca Vittetoe (Region 8): “Rainfall has been pretty sparse over the past two weeks. For the growing season, the counties I cover range in being 4" to to nearly 12" behind normal rainfall, as illustrated in the graphic below. We have gotten a break with the cooler temperatures. According to the U.S. Drought Monitor, this part of the state is still in a moderate to extreme drought. Corn silage harvest has pretty much wrapped up. The corn is moving right long with most in the late dent (R5) to reaching physiological maturity (R6). Keep an eye out for ear molds and stalk rots. I’ve really noticed soybean fields starting to change over the past week. Most soybeans would be in full seed (R6) to beginning maturity (R7), but some fields have reached full maturity (R8).The pastures and alfalfa are starting to look a little better, but could still benefit from some rain.”

Precipitation departure from normal for the 2017 growing season from April 13 to September 13. Source: ISU Mesonet. 

Virgil Schmitt (Region 10): “In the last two weeks we have had rainfall of less than 0.5 inch over nearly all of my counties. With the exception of Jackson County, which received between 2 and 4 inches of rain in the last 30 days, my counties have received less than 2 inches of rain in the last 30 days. The third cutting of hay is nearly complete. Corn is mostly in late R5 stage, with approximately a three-quarter milk line. Soybeans are in the R6 to R7 stage. I have seen a few soybean fields at R8. In general, both corn and soybeans look good from a plant health standpoint. Crops south of Highway 92 are still showing the effects of the drought.”

As harvest approaches, we want to wish everyone a safe harvest season!