Winners of the 2022 WI Soybean Yield Contest are Announced

Division 4:

1st           Don and Doug Midthun, Arlington (96.57 bu/a with Asgrow AG20X9)

2nd          Ron Digman, Mount Hope (96.33 bu/a with Pioneer P28A42X)

Division 3:

1st           Kelley Farms, Arlington (88.33 bu/a with Asgrow AG24XF1)

2nd          Jim Salentine, Luxemburg (74.58 bu/a with Stine 19EC32)

  • *UW Bean Team (Mark Kendall, Andrew Malcomson, Haleigh Ortmeier-Clarke), Madison (84.08 bu/a with Pioneer P20A22X). The UW Bean Team is ineligible for official prizes as they are graduate students of Dr. Conley; however, their efforts are still unofficially recognized.

Division 2:

-No entries were submitted for Division 2-

Division 1: 

1st           Josey W. Wilson, St. Croix Falls (72.44 bu/a with Pioneer P16A84X)

2nd          Jim Wilson, St. Croix Falls (63.89 bu/a with Asgrow AG11X8)

New Contestant Award

  • Daniel Ballmer, Janesville (90.01 bu/a with Dyna-Gro S28XF92)

The contest is sponsored by the WI Soybean Program and organized to encourage the development of new and innovative management practices and to show the importance of using sound cultural practices in WI soybean production.

For more information please contact Shawn Conley, WI State Soybean Specialist at 608-800-7056 or

Finalists for the 2022 WI Soybean Yield Contest are Announced

The finalists for the 2022 WI Soybean Yield Contest were announced today. The top two entries in each division (in no particular order) are:

Division 4:

  • Ron Digman, Mount Hope (planted Pioneer P28A42X)
  • Don and Doug Midthun, Arlington (planted Asgrow AG20X9)

Division 3:

  • Jim Salentine, Luxemburg (planted Stine 19EC32)
  • Kelly Farms, Arlington (planted Asgrow AG24XF1)
  • *UW Bean Team (Mark Kendall, Andrew Malcomson, Haleigh Ortmeier-Clarke), Madison (planted Pioneer P20A22X)

*The UW Bean Team is ineligible for official prizes as they are graduate students of Dr. Conley; however, their efforts are still unofficially recognized.

Division 2:

-No entries were submitted for Division 2-

Division 1: 

  • Jim Wilson, St. Croix Falls (planted Asgrow AG11X8)
  • Josey W. Wilson, St. Croix Falls (planted Pioneer P16A84X)

One New Contestant Award is presented statewide to the highest yield from a first-time contestant that does not place first or second in their geographic division.  The 2022 recipient is:

  • Daniel Ballmer, Janesville (planted Dyna-Gro S28XF92)

The final ranking and awards will be presented in February at the Corn Soy Expo to be held at the Kalahari Convention Center, Wisconsin Dells, during the WSA/WSMB annual meeting.

The contest is sponsored by the WI Soybean Program and organized to encourage the development of new and innovative management practices and to show the importance of using sound cultural practices in WI soybean production. For more information, please contact Shawn Conley, WI State Soybean Specialist at 608-800-7056 or

(SBOC)…..One MORE thing to think about this fall?

By: Seth Naeve and Shawn Conley

Fall is time where farmers literally reap the production of their year’s efforts, but fall can be a crazy and chaotic time as well.  Each year offers new challenges, and this one will be no different.

Farmers in the Midwest should be aware of an issue in the production system that may affect how their soybean deliveries may be handled.  The issue is related to soybean seed coat color and it is important that producers are aware of this prior to harvest.

Soybean seed coats can vary in color based on genetics of the seed, the environment where they are produced, or through infections by disease organisms.  The presence of colored seed coats is not uncommon and the U.S. Federal and Grain Inspection Service (FGIS) includes a measure of seed coat color in its soybean grading standards.  U.S. #1 yellow soybeans are allowed up to 1% soybeans of other colors (SBOC), a general term to note any soybean with off-colored seed coats.  U.S. #2 soybeans may contain up to 2% SBOC.

Following the 2021 harvest season, it became clear that Enlist E3® soybeans can produce soybean seed containing some off-colored soybeans, and the percentage of the seed with this SBOC appearance can be very large.  Not all varieties produce this trait, and this trait may not express itself in all fields.

By May, of 2022, around 32% of FGIS soybean certificates included SBOC of greater than 1%.  So, nearly 1/3 of soybean samples did not make US #1 yellow soybeans due to off-colored soybeans (Images 1, 2 and 3).  In previous years, fewer than 1% of soybean certificates failed to make US #1 due to SBOC (

Image 1. Graded Grain Sample containing a high percentage of SBOC.

Image 2. Closeup of graded SBOC sample.

Image 3. SBOC Highlighted. Image from PJ Liesch.

From a practical standpoint, seed coat color is unlikely to have any effect on the quality of soybean meal or oil produced from these soybeans.  However, significant quantities of US soybeans are exported for food use.  Presence of these off-colored seeds in shipments destined for food use may lead to rejections at either the origin or destination of these shipments.  This increases risk for all in the value chain.

Currently, it appears U.S. soybean processors will be unlikely to implement dockage on soybeans containing over 1% SBOC.  However, elevators that have connections to overseas markets are likely to segregate soybeans by Enlist E3® vs other traits.  While direct dockage to producers may be uncommon, it is very possible that basis levels will be adjusted based on local supply and demand of soybeans for processing and soybeans for export.  Regardless of direct impacts, segregation of commodity soybeans into different markets reduces efficiencies and will lead to additional costs that must be borne by buyers or sellers of soybean.

If concerned, farmers should consider reaching out before harvest starts to their local elevators and/or seed dealers to determine how this issue may be handled locally.

Soybean Flowers, Herbicide Labels, and Wheel Track Damage…Oh My!

Authored by Shawn P. Conley and Rodrigo Werle

We are starting to get the many reports of soybean beginning to flower (R1) in our early planted situations. As we enter the soybean reproductive growth phase there are a few things to keep in mind. The first is that soybean will produce flowers for ~3 to five weeks, depending upon planting date and environment. During that time soybean will abort anywhere from 20 to 80% of the flowers that they produce. Generally it is the first and last flush of flowers produced that are most likely to be aborted.

R1 soybean growth stage

Next, the timing window for many POST-emergence herbicide applications in our early planted soybean are quickly closing if not closed already. Glyphosate labels indicate that applications can be made through R2 or full flower, however the spread of glyphosate-resistant waterhemp and other weeds across Wisconsin and beyond has led several farmers to adopt soybean varieties containing the novel herbicide resistance traits (Xtend [which confers resistance to glyphosate and dicamba],Xtendflex [which confers resistance to glyphosate, dicamba and glufosinate], Enlist E3 [glyphosate, glufosinate and 2,4-D] or LibertyLink GT27 [glyphosate and glufosinate]), which all provide effective herbicide options for POST-emergence broadleaf weed control. The application window for the POST-emergence herbicides associated with the aforementioned traits is also linked to soybean reproductive growth stages.

In Xtend systems, the registered dicamba herbicides Engenia and XtendiMax with VaporGrip Technology can be applied in Wisconsin until June 30 or up until R1 (first bloom; in other words, don’t apply if the soybeans are flowering), whichever comes first. Tavium plus VaporGrip Technology may be applied through the V4 growth stage or prior to June 30, whichever comes first.

In LibertyLink systems (LL, LLGT27, Enlist E3, or XtendFlex), glufosinate herbicides such as Liberty, Interline, etc. can be applied up to bloom or R1 growth stage (don’t apply if the soybeans are at R2 stage or advanced).

In Enlist E3 systems, the registered 2,4-D herbicides Enlist One and Enlist Duo should be applied through R1 growth stage.

When deciding the best time for a POST application, target small weeds, follow all label requirements and don’t spray under adverse environmental conditions.

Soybean developmental note: on average it takes ~ 4 days to move from R1 (beginning flower) to R2 (full flower) and ~10 days from R2 to the start of R3 (beginning pod).

Last but not least, wheel track damage made from ground applications may start to reduce yield. Sprayer wheel traffic from first flower (R1) through harvest can damage soybean plants and reduce yield (Hanna et al. 2008). Our research suggests that an adequate soybean stand (more than 100,000 plants per acre) planted in late April though mid-May can compensate for wheel tracks made when a field is sprayed at R1. Yield loss can occur, however, when wheel tracks are made at R1 or later in thin soybean stands (less than 100,000 plants per acre) or late planted soybeans. Regardless of stand, plants could not compensate for wheel tracks made at R3 (early pod development) or R5 (early seed development). The average yield loss per acre is based on sprayer boom width (distance between wheel track passes). In our trials yield losses averaged 2.5, 1.9, and 1.3% when sprayer boom widths measured 60, 90, and 120 foot, respectively. Multiple trips along the same wheel tracks did not increase yield loss over the first trip.

Spraying soybean at the R1 crop growth stage
Wheel track damage to drilled soybean at R1

Hanna, S., Conley, S. P., Shaner, G., and Santini, J.  2008.  Fungicide application timing and row spacing effect on soybean canopy penetration and grain yield.  Agronomy Journal: 100:1488-1492.

Adjust Your Seeding Rate (Higher) But Not Your Maturity Group For Late May Planted Soybean

Adapted from original article written in 2018 by Authors: S.P.Conley, J.M Gaska, S. Mourtiznis, D. Mueller, and A. Varenhorst

With only 7 days left in May and roughly only 49% of the WI soybean crop planted what if any production changes should growers consider modifying?

  1. Do Not Switch Your Maturity Group….Yet: Do not consider switching to an earlier soybean maturity group until ~June 1. After June 1 do not go any earlier than a 0.5 MG earlier variety. For more information please see:  Soybean Planting Date and Maturity Group Considerations Moving into 2019.
  2. Increase your seeding rate to roughly 154,000 seeds per acre. Efficacy of soybean seed-applied fungicide and insecticide at early and late planting dates and a range of seeding rates were tested in multiple states during the 2016 and 2017 growing seasons. Researchers in Iowa, South Dakota, and Wisconsin participated with 4 locations each year for a total of 24 location/years.  Seed treatments included a) UTC, b) fungicide (prothioconazole, penflufen, and metalaxyl), and c) fungicide+insecticide (clothianidin). Only late planting dates were used in this below analysis. The average of the late planting dates for each state over the two years were: IA: May 24,  SD: June 21, and WI: May 31.  Seeding rates were in increments of 20,000 from 60,000 to 160,000 seeds/acre. There was a quadratic yield response to seeding rate that was significant (Figure 1). Maximum yield was observed at 154,000 seeds/acre. The curve is not very steep which shows that practical yield differences between seeding rates were not large. So, the curve does not tell the whole story. We re-ran the model with seeding rate as a categorical variable. The results suggest that yields for 140 and 160K were not different and 100-140K were not different either (Table 1). It may be argued that our seeding rate was not extended high enough…I assume my Twitter “friends” will come back and say “hey bean boy why didn’t you go to 180 or 220,000 seeds per acre”. That is a valid critique however given the flat response curve we find it difficult to believe we would have seen a significant yield response above where we are. As a reminder our recommended seeding rate for early planted soybean can be found here: The Soybean Seeding Rate Conundrum.
  3. Interpret the below information on return above seed cost cautiously. The best part of writing in a blog format is that you get to tweak the post after it is originally published. To that point we had several comments last year on the the small yield response difference between seeding rates and question the optimal farmer return above seed cost. If you were to look only at that factor the optimal seeding rate would be ~100,000 seeds per acre even at a late May planting (Table 2). Though those economic numbers are very appealing I would caution growers to not go this low if they have uneven or rocky fields as harvestabilty will be a challenge with a lower soybean pod set. Furthermore many soybeans will be “planted” and I use that term loosely into unfavorable environments (cold, wet and compacted soils) and emergence issues will be likely. I would also not go this low in fields that are prone to drought as the rows will be slower to canopy and lead to greater soil water evaporation and subsequent weed competition. This leads us to waterhemp and its wonderful biology of delayed germination and prolific seed set. The point I am trying to make is this is a system and as Paul Harvey so eloquently stated……”now for the rest of the story”!
  4. Figure 1. Soybean seed yield response to seeding rate for soybean planted in Late May and June in IA, WI, and SD.

Table 1. Mean soybean seed yield response to seeding rate for soybean planted in Late May and June in IA, WI, and SD.

Soybean seeding rate

(1000 seeds per acre)

Soybean Seed Yield

(bu per acre)

160 67.3 A
140 66.6 AB
120 66.0 B
100 65.8 B
80 63.8 C
60 61.6 D
Tukey-Kramer Least Squares Means (Alpha=0.05); LS-means with the same letter are not significantly different.

Table 2. Return above seed cost at various market prices for seeding rates over 60000 seeds/acre.

Seeding rate


Yield difference compared to 60000 seeds/a

Soybean market price ($/bu)









——– ——– $/acre —————







12.70 14.90 17.10 19.30 21.50



23.40 27.60 31.80 36.00 40.20



16.10 20.50 24.90 29.30 33.70



12.90 17.90 22.90 27.90 32.90



10.60 16.30 22.00 27.7 33.40
Based on $65.00/140000 seeds

Soybean Replant Decisions: Just the Facts Jack!

The start of the #plant22 growing season has been significantly less favorable than #plant21 for many Midwestern farmers. According to today’s NASS report for WI: Soybean planting was 26 percent complete, 9 days behind last year and 2 days behind the average. Soybeans emerged was 1 percent, 12 days behind last year and 8 days behind the average. Today we are starting to see the first wide spread images of soybean beginning to crack and emerge in WI. As farmers, agronomists and technical service providers begin to assess the 2022 soybean stands here are a few items to contemplate before re-plant recommendations are made.

  1. Get an accurate stand assessment. We are often drawn to the worst areas of fields and over-blow how bad the overall stand really is. You can go old school and use the tape or hula-hoop method or try a digital approach such as Bean Cam the WSMB funded soybean replant app!
    1. Link to the app store for iPhone and iPad
    2. Link to the app store for Android

      Bean Cam app calculations/results.

  2. An effective stand is obviously important to maximize soybean seed yield. However the downside yield risk for a sub-par stand is minimal until stands fall below 50,000 plants per acre. The synergy of early planting coupled with breeders adding 3x yield to soybean branches at low populations have effectively reduced the yield penalty for thins stands by 1/2 (Suhre et al. 2014) . Therefore we recommend the following.
    • Early planted soybean yield is maximized with stands that range from 100,000 (high yield environment) to 135,000+ (low yield environment) plants per acre.
    • When soybean stands are less than 50,000k plants per acre, inter-plant new seed with a similar maturity into the existing stand. DO NOT TEAR UP THE STAND AND START OVER.
    • When stands fall between optimal and 50,000k plants per acre Think Twice Before Replanting Soybeans! Our data shows a nominal ~2 bu yield increase in this situation. Even if you have a “free replant” guarantee the numbers don’t make economic sense. As a grower you are better off investing $$$ in an effective in-season residual herbicide to control weeds such as Palmer and waterhemp.


Gaspar, A. and S.P. Conley. 2015. Responses of canopy reflectance, light interception and soybean seed yield to replanting sub-optimum stands. Crop Sci.55: 377-385. doi: 10.2135/cropsci2014.03.0200

Suhre, J.J., Weidenbenner, N., ‡Rowntree, S., Wilson, E., S., Naeve, S. Casteel, S.P. Conley, Diers, B., Esker, P., Specht, J., and Davis, V. 2014. Soybean Yield Partitioning Changes Revealed by Genetic Gain and Seeding Rate Interactions. Agron. J. 106:1631–1642.

Just the Facts Jack: Soybean Planting Date, Seeding Rate and Seed Treatment Recommendations

When I am asked a direct question from a farmer or a crop consultant my response is always as follows…Do you want the short answer or the long answer as I can say the same thing in 5 minutes or 5 hours. Their response to me is almost always the same…”Just the Facts Jack”. In this blog I will attempt to answer three very agronomically important and challenging questions in a very succinct manner.  However as we all know brevity can be a gift or a curse depending upon the context of the question. With that being said here we go!

Question #1. When should I start planting soybean? My general response is to start planting your soybean crop ~7 to 10 days before you start putting your corn in the ground with the caveat that the soil is fit and you are following your crop insurance replant dates (FYI: a team of us are revisiting the RMA dates for U.S. soybean growers). We have measured soybean yield loss due to delayed planting date as early as ~April 25th however the rapid yield decline (up to 0.5+ bpa per day) occurs at ~May 10th. As you would expect the magnitude of this planting date yield response is soil and climate dependent and yield losses in some areas (TED’s) where as high as 2.8 bpa per week for delayed planting (Figures 1 and 2). For a deeper dig please review the below supplemental documents.


Figure 1. Map of the North Central US region showing nine technology extrapolation domains (TEDs) used in this analysis.

Figure 2. Producer soybean yield plotted against planting date in 9 technology extrapolation domains (TED) in the NC USA region.

Question #2. What is the optimal soybean seeding rate? The quest for the optimal agronomic soybean seeding rate for yield vs. the optimal economic seeding rate has been an ongoing debate. Fortunately a large group of academics and industry (thank you Corteva) were able to combine data sets and address this question (Figure 3). Our results suggest that for “on-time” soybean planting dates the optimal agronomic soybean seeding rate to achieve 99% yield potential ranged from 237,000 to 128,000 seeds per acre (assuming 90% germ) across environments; whereas the optimal economic soybean seeding rate ranged from 157,000 to 103,000 seeds per acre. Thankfully this roughly confirms my original recommendation that you buy a bag an acre (140K) and place ~20% more seed on the low yielding acres and ~20% less on the high yielding acres. If planting is delayed however we do recommend that you increase your seeding rate accordingly (Adjust Your Seeding Rate (Higher) But Not Your Maturity Group For Late May Planted Soybean ). For a deeper dig please review the below supplemental document.

 Location of 211 trial site-years that are included in the database and their respective environmental cluster classifications.

Figure 3. Location of 211 trial site-years that are included in the database and their respective environmental cluster classifications.

Table 1. Agronomic and Economic Optimal Soybean Seeding Rates by Environmental Cluster.

Cluster 1

Cluster 2

Cluster 3

Yield level (bu a-1)

Agronomic/(Economic) Optimal Seeding Rate1,2

< 58




58 – 71




> 72




1Agronomic optimal seeding rate (x1000 seeds) based on 99% maximum yield level.

2Economic analysis based on $62 a unit (140k) for seed and $9 a bushel pricing; soybean price and seed cost fluctuations will change the EOSR.

Question #3. When do I use a soybean seed treatment? I purposely placed this questions last as I know it will draw significant ire; however the data are what they are. Soybean seed treatments should only be used in some early planted soybean situations and/or if you have a history of or have scouted for an insect (i.e. Bean leaf beetle) or a pathogen (i.e. SDS) that exceeds economic thresholds. For a deeper dig please review the below supplemental document.

Th-th-th-that’s all folks!

The WSMB Free Soybean Cyst Nematode Testing Program is Back in 2022!

Ann MacGuidwin, Damon Smith and Shawn P. Conley

The WI Soybean Marketing Board (WSMB) sponsors free nematode testing to help producers stay ahead of the most important nematode pest of soybean, the soybean cyst nematode (SCN). Eggs of SCN persist in the soil between soybean crops so a sample can be submitted any time that is convenient. The soil test report indicates the number of eggs in the sample and is useful for selecting the right variety for the next soybean crop. Retests of fields planted with SCN-resistant varieties over multiple years shows how the nematode population is responding to variety resistance and provides an early warning should the nematode population adapt to host genetics.

In the spring of 2012, the WSMB expanded the nematode testing program to include other pest nematodes in addition to SCN. These nematodes are less damaging to soybean than SCN but can cause enough yield loss to warrant treatment. As is the case for SCN, there are no rescue treatments for nematodes so the primary purpose of this year’s soil test is to plan for next year’s crop. Soil samples collected in corn for nematode analysis have predictive value for explaining yield if they are collected before the corn V6 growth stage. Sampling early in the season will provide information about the risk potential for the current corn crop AND the next soybean crop.

The assays used to recover nematode pests other than SCN in soil require that the nematodes are alive. So, it is important to keep the samples moist and at least room temperature cool. Collecting a sample that includes multiple cores ensures that there will be plenty of root pieces to assay. It is not necessary to include live plants in the sample. The soil test report will indicate which pest nematodes are present and at what quantities and their damage potential to soybean and corn based on the numbers recovered.

For more information on SCN testing and management practices or to request a free soil sample test kits please contact: Jillene Fisch at (

Click to view more information on our WI SCN testing program or visit The SCN Coalition.

Remember the first step in fixing a nematode problem is to know if you have one! The WSMB sponsored nematode testing program provides you that opportunity. So Wisconsin farmers….”What’s you number?”

Winners of the 2021 WI Soybean Contest are Announced

Division 4:

1st           Ron Digman, Mount Hope (107.19 bu/a with Pioneer P28A42X)

                     *Inducted into WI 100 Bushel Soybean Club

 2nd          Don and Doug Midthun, Arlington (97.95 bu/a with Asgrow AG20X9)

Division 3:

1st           Jim Salentine, Luxemburg (97.57 bu/a with Stine 20EB23)

–Only one entry was submitted for Division 3–

Division 2:

1st           Scott Peavey, Woodville (98.34 bu/a with Asgrow AG11X8)

2nd          Mike and Dean Wegner, Sparta (79.43 bu/a with Pioneer P18A33X)

Division 1: 

1st           Jim Wilson, St. Croix Falls (80.09 bu/a with Asgrow AG11X8)

2nd          Josey Wilson, St. Croix Falls (76.15 bu/a with Pioneer P16A84X)

Soybean Quality Contest

1st           Jim Salentine, Luxemburg (3,085 pounds of protein plus oil per acre with Stine 20EB23)

The contest is sponsored by the WI Soybean Program and organized to encourage the development of new and innovative management practices and to show the importance of using sound cultural practices in WI soybean production.

For more information please contact Shawn Conley, WI State Soybean Specialist at 608-800-7056 or

Best Management Practices for Growing Second or Third Year Soybean

Originally Coauthored by: Shawn P. Conley, Seth Naeve and John Gaska December 14, 2016. Modified by S.P.Conley 1/22/18.

Modified by S. P. Conley, E. G. Matcham, and L. C. Malone 12/15/2021.

Before we start, we fully acknowledge our title “Best management practices for growing second or third year soybean” is a bit misleading as we do not advocate this practice (it’s not a BMP!) but we thought we could sucker you into reading this article if it had an enticing title!

This article was originally updated in 2018 when the USDA announced that U.S. soybean acres in 2018 will surpass U.S. corn acres. These acres have to come from somewhere and many of them will be from second-year soybean.With input costs rising rapidly, especially for nitrogen fertilizers, we thought it was time for another update. Many of our management recommendations remain the same, but we also have some additional recommendations based on recent crop rotation and nutrient management research.

With that being said, here are some recommendations to consider:

  • Balancing short-term versus long-term profitability (i.e., economic sustainability). Every year promises of short-term profitability may drive some farmers to consider planting soybean after soybean, rather than rotating, data from our long -term rotation experiment clearly shows the benefit of crop rotation to the soybean crop. It is amazing that after 5 years of corn, it only took 3 years of continuous soybean for the yield to drop to within 7% of continuous soybean (20+ years) yield levels whereas 2nd year soybean yielded within 5% of soybean in a corn-soybean rotation. We could hypothesize then that the yield of the 3rd year of continuous soybean (in our experiment) would be like a 2nd year of soybean in a corn soybean (C-S-S) rotation. Our data clearly shows that 3 or more years of continuous soybean gives you a 7+ bu per acre hit when compared to a corn-soybean rotation and moves you close to the yield levels of continuous soybean. In short, you are setting your long-term profitability up for a hit. Another long-term rotation study we have (19 years) shows an even bigger yield benefit (13%) to rotating away from soybean for two years (corn and wheat) compared to annually rotating corn and soy.

  • Be aware that soybean after soybean will alter the pest relationship complex in your fields. Some of these alterations may take years to undo as you will be making a long-term impact on your soil and resulting soil health. We looked at soil fungi in our long-term rotation study and found increased Fusarium (which causes damping off in soybean) in continuous soybean plots. On the “good microbes” side of things, soybean isn’t a great host of AMF, a fungus that helps take up water and phosphorus, and rotating away from better hosts like corn for more than a year can decrease AMF populations in your field that other crops might benefit from. Read more about this soil fungi data here.
  • Also don’t automatically think that simply adding a cover crop to this S-S rotation will “fix” these issues. In an Ohio study, rye cover crops only increased yields by 2-6 bu/acre and did not impact disease or insect pressure compared to control plots without cover crops.
  • Plant a different variety than was planted in that field the previous year and make sure it has strong disease resistance traits to the problems you have in that field! Every variety has a weakness and planting the same variety on the same land 2 years in a row will expose that weakness. Note that these varieties must be truly different.  The same bean in a different color bag will greatly increase your risk of disease losses.  Please see our 2021Wisconsin Soybean Variety Performance Trials for information.
  • Test for SCN and select SCN resistant varieties. SCN proliferates in long-term soybean cropping systems. Control weeds that are alternate hosts for SCN like field pennycress, shepherd’s-purse, and chickweed and do not plant leguminous cover crops that can be an alternative host for SCN. Be prepared to scout your fields more intensively to get ahead of any disease problems. Increased disease pressure is likely to be more pronounced in no-till fields and may provide an opportunity to see yield responses from fungicides and insecticides. Include the cost of additional crop protection applications in your economic estimates for short-term profitability.
  • Keep seeding rates lower if white mold was a problem in the field
  • Use a seed treatment at the max a.i. fungicide rate.
  • Use a pre-emergence herbicide and use multiple modes of action. If you had weed escapes, expect even larger problems in soybean after soybean.
  • Soil sample and replace K if needed: An 80-bushel soybean crop meant you removed ~98 pounds per acre of K20 equivalent fertilizer. Growers often routinely rely on carryover fertilizers for soybean when rotated with well-fertilized corn. Soybean after soybean may require additional fertilizer, especially K.

Back on the soil microbe note, we looked at the soil bacterial communities under corn-soybean rotation (5 years of corn followed by 5 years of soybean). These communities are affected by a lot of factors, like pH, moisture, and nutrients, along with the plants growing there. The figure below shows ordinations of bacterial communities – each point on the graph is a plot in our field experiment, and the further apart points are, the more different those communities are. This figure focuses on soybean phases. The main point here is that the first and second year of soybean after 5 years of corn are pretty similar to each other, while the 3rd, 4th, and 5th year of soybean start to look more like the continuous soybean (30+ years). This trend might remind you of the yield trends discussed earlier in this post! Bulk soil microbial communities are complicated, and they take a long time to change…sticking with soybean for one extra year may not shift the community drastically, but 3+ years is more likely to. The data from this study isn’t published yet, but if you are curious about bacterial communities and corn/soybean rotation in the soil you can read more here.

Additional recommendations for years 3+:

  • Even if you only saw an increase in disease pressure without an increase in insect pressure in year 2 beans, expect to see an increase in both diseases and insects in year 3+. Budget accordingly for crop protection products.
  • Consider increasing your seeding rate in fields with high pressure for seedling diseases such as pythium or phytophthora. Don’t increase your seeding rate in fields with high white mold pressure.
  • Soybean removes more K and S per acre than corn. Consider increasing soil sampling frequency to monitor K levels, and scout fields regularly for S and micronutrient deficiencies.