Iowa Crop Update for June 5 to June 13, 2017

The USDA Weekly Crop Progress Report showed that Iowa's corn crop is 96% emerged and gave Iowa’s corn crops a 77% good to excellent rating. Soybean planting is 98% completed and 85% of Iowa’s soybeans have emerged. The USDA gave Iowa’s soybean crop a 74% good to excellent rating. The season started off on the wet and cool side, but has gone to being hot and dry.

Map showing rainfall totals for Iowa over the last 30 days. Source: http://www.weather.gov.  

Issues showing up in Iowa's crop fields include emergence concerns, nutrient deficiencies, and herbicide drift. Read on for more information about your region's crop progress and field conditions from Iowa State University Extension and Outreach field agronomists.

Northwest Iowa

Joel DeJong (Region 1): “Scattered locations in NW Iowa received a rainfall in the past week, but most of those areas were limited in size. Rainfall has been pretty rare since about May 20, and when you add in higher than normal temperatures and wind, corn plants show the stress in the afternoons. Soybeans are mostly emerged, but there were a lot of acres that struggled with emergence. These were mostly planted on either May 16 or 15. Rain and cold immediately after planting caused crusting and vigor issues, I believe. Most replanted without tearing up the existing stand – and were afraid that if tilled there would be no moisture left to get the replanted beans started. Corn herbicide applications have progressed well, but hot afternoons have chased applicators out of the field on several days. The first crop of alfalfa has been harvested.”

Paul Kassel (Region 2): “Soil conditions were on the wet side three weeks ago – with many farmers worrying about finishing soybean planting. Now, after a week of 90+ temperatures and 30+ wind speeds –some scattered rain showers were more than welcome. There have been reports of seed furrows that opened up and corn plants that have poor root systems that were hanging on by their seed roots systems. Also, there is some soybean seed that is in dry soil. Hopefully, the recent rains were adequate enough to remedy both situations. Corn is mostly in the V5 to V7 stage. The soybean crop is mostly in the V1 to V2 stage. A few farmers will be starting to apply post-emergence herbicides to the soybean crop this week.”

This Buena Vista county corn field not far from shading the rows. Photo by Paul Kassel. 

North Central Iowa

Angie Rieck-Hinz (Region 3):  “Corn is V4 to V8.  Recent winds and high temperatures are causing corn to roll by mid-morning.  Soybeans are V1 to V3.  I continue to receive calls with concerns about emergence from crops planted the week of May 15 to May 19.  Herbicide drift complaints were also the theme of last week.  Controlling weeds before they get too large is important, but so are wind speed and direction. Even with the warm temperatures of the last week, we are still running slightly behind the long-term average for growing degree days in north central Iowa (depending on when you planted). Precipitation shows we are lagging just a bit behind for June 1-June 11, with Eldora 1.75 inches behind the long-term average for the first 11 days of June and Mason City 1.07 inches behind average.”

Southwest and West Central

Mike Witt (Region 11):  “Corn ranges between V3 to V7 and the farthest along soybeans are V2. We are pretty dry and could use some rain. Issues that are showing up in crop fields include nitrogen banding in corn fields, soil crusting, and delayed soybean emergence. There have also been questions about scouting for Palmer amaranth in CRP.”    

Southeast and East Central:

Rebecca Vittetoe (Region 8):  “It’s been about 20 days since we’ve seen a really measurable rainfall in most of my counties, and we could really use a shot of rain. Most of the corn is V6 to V9 and has entered that rapid growth stage. I have noticed some sulfur (S) and potassium (K) deficiencies showing up in fields. Also, it was not uncommon to see corn leaves rolling Sunday, Monday, and Tuesday. Soybeans are VC to V2. I’ve had a few calls with emergence issues due to soil crusting. Not only have the crops grown considerably the past week, but so have the weeds. Pay close attention to weed size when out scouting and deciding when to spray as well as the conditions you are spraying in. On the forage side, most first cuttings of hay have been completed, and both the pastures and alfalfa fields could use some rain.”

 
Nutrient deficiencies (sulfur left and potassium right) showing up in fields this growing season. The question becomes is it really deficiency or because of environmental conditions? Photos by Rebecca Vittetoe. 

Virgil Schmitt (Region 10): “Except for a small area in western Jackson County that received a little over 0.5 inches of rain last week, the rest of my area received 0.0 to about 0.1 inches of rain last week. We are in need of a good rain. Harvest of first cutting hay pretty well wrapped up last week. Corn is mostly at V6 to V8. We are starting to see some sulfur (S) deficiency symptoms and also some light colored flag leaves due to rapid growth tying leaves up. Soybeans are mostly V1 to V3. Armyworms, herbicide injury, and herbicide drift were the major items last week.”

Map showing rainfall totals for Iowa over the last week. Source: http://www.weather.gov.  

Find your local ISU Extension and Outreach field agronomist here!