ILSOYADVISOR POST

Agronomy: Post Season Soybean Evaluation

When it comes to producing high-yield soybeans, knowing the details count.

By now most fields of full-season soybeans have been harvested. It probably felt good to combine that last acre of beans for the season and be done.

But your work isn’t over yet. As harvest ends and fall work slows down, take time to evaluate how your soybeans did overall and in individual fields. And do this before you make your soybean variety decisions for next season.

Mastering soybean production to produce consistently high yields is about understanding limitations and fine-tuning management practices. And it’s true that soybeans respond to management just like corn, but they are a little more fickle and you need to pay closer attention to the crop. With soybeans you need to identify limiting factors and learn to optimize every production factor on every field planted to soybeans. And some limiting factors aren’t easily recognizable.

Not surprisingly, weather was a deciding factor in 2015. Ample and even excess rain delayed planting, led to replanting or forced growers to take preventative planting. Soybeans were planted late, not always in ideal conditions, and weed control was a problem. However, all that moisture along with moderate temperatures led to soybean yields greater than average and yields were often similar to 2014. Of course there were fields that fell short of that due to excessive rain. When it comes to soybean production, weather is always a big influencer or equalizer. The impact of weather can negate the performance of a particular practice in any given year.

With all that rain, followed by a mild late summer, there was a noticeable absence of diseases and insects. This took a lot of pressure off the crop after an unsteady start. Diseases like Cercospora leaf spot, brown spot, sudden death and white mold never had a major impact on the crop in Illinois. And populations of aphids, bean leaf beetle and Japanese beetle were often not present or very low. Of course the unseasonably warm end to the season and a soil profile with ample moisture let beans fill out.

So after you consider the impact of weather on the 2015 crop start to look back on your practices.
• Did you plant on time?
• Was your row spacing and population right?
• Did you use the right seed treatments?
• Was the field weed-free at planting or emergence?
• Did you see signs of seedling blight or insect feeding?
• How was stand establishment and did you reach your target population?

I believe weed control was one of the biggest crop challenges in 2015. Evaluate how your weed control plan worked. Did the residual herbicide fail to control weeds due to excess rain? Were you unable to do an early post spray? Were there weed escapes and are glyphosate-resistant weeds like Palmer amaranth or waterhemp becoming an issue?

How did you foliar application program work out? Did your insecticide or fungicide treatment work and was it really worth the investment in 2015? If you applied a foliar nutritional did it help keep the plant growing? With the pressure on soybean prices and the need to shave costs, can you save on foliar applications or are they a must?

Take time to assess yield maps and aerial images. Yield monitors are good tools for monitoring both yield and moisture during harvest. In addition, the maps they create contain a wealth of information about the field and how management practices worked. Aerial or satellite images reveal similar information, but instead of yield they show where stress occurred. And today you can deploy drones up close and personal to really focus in on stress areas and look at the symptoms more closely.

Lastly, when assessing your crop look at performance in terms of three areas:
• How did your initial production plan perform and does anything need tweaking?
• What factors might have limited growth and yield throughout the season?
• How did any add-on agronomy practices or products perform?

Use this information and what you learned from your 2015 crop to develop a record-breaking plan for 2016.

Agronomist Dr. Daniel Davidson posts blogs on agronomy-related topics. Feel free to contact him at djdavidson@agwrite.com or leave a comment below.


Dan Davidson
Soybean agronomist Daniel Davidson, Ph.D., posts blogs on topics related to soybean agronomy. Feel free to contact him at djdavidson@agwrite.com or ring him at 402-649-5919.


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