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Vol 1 Issue 2 August 19, 2021

NW Iowa Crop News

Newsletter for current topics in crops for the counties of Buena Vista, Clay, Dickinson, Emmet, Hancock, Kossuth, Palo Alto, Pocahontas, and Winnebago Counties.

Gentry Sorenson

Extension Field Agronomist


Iowa State University Extension and Outreach

1121 Hwy 18 E Algona, IA 50511

Phone 515-295-2469



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Special Drought Update

Iowa Drought Monitor

On August 5th parts of Dickinson, Clay, Kossuth, and Emmet were moved from the D2 Severe Drought to the Extreme Drought D3 category. The D3 Extreme Drought is defined by historical impacts such as dry pastures where cattle have to be sold, high feed prices, pest infestations in crops, and trees that may drop leaves.

The updated drought monitor map from August 19 extended the D3 intensity into western Kossuth as well as added parts of Palo Alto county. In the above link it shows the areas of Iowa that have been upgraded to the D3 Intensity.

The remainder of the area I serve is in a lower category of drought defined as D2. D2 historical defined impacts are defined as lower mosquito populations, high fire danger, and corn that may have low yields.

Recent rains have been variable all season with most areas not receiving enough rainfall causing drought stress to the crop. At this point we will be needing a consistent rain to help minimize losses with corn and help hold some test weight. Rain will also help if we get it very soon to help finish out the soybeans and reduce pod loss. In soybean fields that I walked this week I observed some pods being aborted from the dry conditions. On the Integrated Crop Management website there are several drought resources that are available. Here is the link to the Drought Resources You are also welcomed to call or email with any questions.

In addition, open communication with your insurance representative regarding your crop if you have not already. Scout your fields to understand the issues present and share those issues with your insurance representative.

Current News

Soybean Drought Stress

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Long term drought stress in soybeans results in reduced number of pods and flower abortion in plants. Drought can also result in soybean plants maturing earlier along with shortening of the grain filling period which results in lower yields. Nitrogen fixation by soybean nodules can also slow during periods of drought because of dry weather. Evaluation of the soybean nodules can be done by digging up a plant root and splitting a nodule. A healthy nodule will be pink or a red color. A nodule that is not active is a black color when split.

Drought In Soybeans

Drought Stressed Corn

Many fields are short on rainfall this year. I am seeing tip back (abortion) of corn kernels on the ear in many fields that I have visited. This is caused from stress such as severe drought stress, excessive heat, and overcast and cloudy conditions. All of these conditions have been prevalent that has lead to tip back on the corn ear. Many fields that I have visited are currently in the R5 or dent stage. At this stage decreased kernel weight can result from severe drought and heat stress and can result in early black layer formation. I have added a link below that reviews drought stress in corn for more in depth evaluation.

Drought effects on corn and soybeans

Northern Research Farm Fall Field Day

On September 9th the Northern Research Farm Association will host the Northern Research Farm Fall Field Day. The field day will have various speakers as well as lunch. Please RSVP by contacting the Wright County Extension Office at 515-532-3453 by September 7th.

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