Soybean Replant Decisions: Just the Facts Jack!

Though farmers continue to struggle to get their crops established in #plant19 we are starting to see the first images of soybean beginning to crack and emerge. As farmers, agronomists and technical service providers begin to assess the 2019 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.

References:

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.

First thoughts on managing your prevent plant acres

I want to start out this blog being very clear and honest…… I don’t exactly know what the right answer is! However as I have stated before, the best thing about blog articles is that it is a dynamic format and can be rapidly updated and changed. I am sure this blog article will change weekly (maybe daily) as we learn more and I get feedback on this article. So let’s get into it. I think we all agree we need to put something on these fields to not only hold the soil but also manage our weed populations, especially waterhemp. To that end I had two farmers call me this week and ask what would happen if they planted winter rye in June. That is a good question I said so I reached out to many colleagues and we all agreed that yes that was a good question, but none of us had done it to date. Our collective thought was that winter rye or winter wheat (I think rye would be better) would grow 18″ up to maybe 4′ tall, stool out and put out multiple tillers since the plant will not vernalize and induce reproduction. This should develop a fairly rapid and robust canopy that can be very competitive with weeds. Speaking with Fred Kolb at UI, he thought that oat would also be a good cover as it would develop well put out seed heads, and if worked into the soil in the fall, reseed the system and then winterkill so you wouldn’t need to worry about termination next spring. For all of these crops I would target 750,000 to 1,000,000 seeds per acre as a seeding rate (WAG). Obviously this is not a perfect system as there may be some herbicide carryover issues from last year’s crops and we would be planting 100’s to 1000’s of acres that may serve as a green bridge for plant pathogens, but that is potentially next years problems. I encourage anyone reading this article to send me thoughts, feedback or other ideas. I am sure someone has tried this and I would like to add in your experiences.

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 11 days left in May and roughly only 19% of the Midwestern soybean crop planted (WI:12%, IA:27%, SD:4%) 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

Yield difference compared to 60000 seeds/a

Soybean market price ($/bu)

7.00

7.50

8.00

8.50

9.00

seeds/a

bu/a

—–bu/a—–

——– ——– $/acre —————

60000

61.6

Base

80000

63.8

2.2

6.11 7.21 8.31 9.41 10.51
100000

65.8

4.2

10.83 12.93 15.03 17.13 19.23
120000

66.0

4.4

2.94 5.14 7.34 9.54 11.74
140000

66.6

5.0

-2.14 0.36 2.86 5.36 7.86
160000

67.3

5.7

-6.53 -3.68 -0.83 2.02 4.87
Based on $65.00/140000 seeds

Soybean Management Strategies to Facilitate Timely Winter Wheat Establishment in 2019

Adapted from original article written by Dr. Adam Gaspar and Dr. Shawn P. Conley

Winter wheat acres across WI have declined over the past few years due to late grain harvests, disease concerns (FHB or scab) and poor wheat prices, however anyone that lives and works in WI knows that a base number of cereal acres are needed to support the dairy industry (straw and land to summer haul manure). As farmers get ready to kick off the 2019 growing season here are a few suggestions to help get your 2019/20 winter wheat crop established on time.

  • Plant early. If weather and soil conditions allow for it plant the acreage you intend to go to winter wheat first. This is regardless of which crop you plan to follow (soybean, corn silage or field corn). Remember the optimal planting date window for most of our WI winter wheat acres is the last week of September through the first week in October. In table 1 below you will notice that for every 3 days soybean planting is delayed we see ~1 day delay in beginning maturity (R7), so delaying planting by one week equates to about 2 days later maturing. However when planting is delaying past June 1st it turns in to more of a 1: 1 relationship. Also remember in WI it normally takes another 5-8 days for the soybean crop to move from R7 to R8 (full maturity).

Table 1. Calendar date for reaching R5 (beginning seed fill) and R7 (beginning maturity) growth stage by planting date and maturity group for the 2014, 2015, and 2016 growing seasons at Arlington and Hancock, WI.

Date of Growth Stage Initiation
R5
R7
Planting Date
Maturity Group
Arlington
Hancock
Arlington
Hancock
May 1st
2.5
3-Aug
4-Aug.
14-Sept.
15-Sept.
2.0
30-July
1-Aug.
9-Sept.
14-Sept.
1.5
26-July
29-July
3-Sept.
9-Sept.
May 20th
2.5
7-Aug.
9-Aug.
18-Sept.
20-Sept.
2.0
3-Aug.
7-Aug.
14-Sept.
18-Sept.
1.5
3-Aug.
4-Aug.
6-Sept.
15-Sept.
June 1st
2.0
11-Aug.
12-Aug.
18-Sept.
24-Sept.
1.5
10-Aug.
9-Aug.
16-Sept.
18-Sept.
1.0
7-Aug.
8-Aug.
10-Sept.
14-Sept.
June 10th
2.0
15-Aug.
17-Aug.
25-Sept.
30-Sept.
1.5
14-Aug.
16-Aug.
20-Sept.
25-Sept.
1.0
11-Aug.
14-Aug.
16-Sept.
18-Sept.
June 20th
1.5
21-Aug.
21-Aug.
27-Sept.
2-Oct.
1.0
18-Aug.
18-Aug.
24-Sept.
26-Sept.
0.5
16-Aug.
16-Aug.
19-Sept.
22-Sept.
  • Consider an earlier maturity group soybean. Plant a high yielding, earlier maturity group soybean to help get that soybean crop harvested on time. Though later maturing varieties “on-average” produce the greatest yields, data from our 2018 WI Soybean Variety Test Results show the maturity group range that included a starred variety (starred varieties do not differ from the highest yield variety in that test) was 2.1-2.9, 1.8-2.4, and 1.8-2.0 in our southern, central and north central regions respectively. This suggests that the “relative” maturity group rating is trumped by individual cultivar genetic yield potential. Therefore growers have options to plant an early maturity group soybean that will be harvested on time and not sacrifice yield.
  • Crop rotation matters. Our long-term rotation data suggests winter wheat yields are greatest following soybean then followed by corn silage and lastly corn for grain.  Therefore plan your rotation accordingly to maximize yield and system efficiency.
  • Manage for the system not necessarily the crop. If you are serious about maximizing wheat grain and straw yield on your farm one of the biggest contributing factors for both of these in WI is timely wheat planting. Make management decisions to facilitate that. *We all know what inputs can extend soybean maturity that don’t necessarily guarantee greater yields. So instead of listing them and fielding angry emails I am being strategically vague here*  In a recent study I would note that across years and environments we did quantify a %RYC (percent relative yield change) swing of -4.1% to 11.2% among various soybean inputs so balance that against a loss of 10-20 bushels of wheat grain yield and 0.5 tons of straw?

As we all know mother nature holds the ultimate trump card on whether we will get our winter wheat crop established in that optimal window. These aforementioned strategies are relatively low risk to the farmer and regardless of what weather patterns we run into are agronomically sound.

Factors to Consider While Assessing Your 2019 Winter Wheat Crop Stand and Spring Nitrogen Timing

As we begin to contemplate spring and the 2019 winter wheat growing season, many growers and consultants alike are beginning to venture out and across their winter wheat fields to assess winter injury and nitrogen timings. Though it is a bit premature to make any rash decisions regarding crop destruction here are a few considerations for assessing your spring 2019 winter wheat stands.

  1. As you look across your wheat landscape vibrant green patches will be interspersed with drab brown areas. The brown areas do not necessarily indicate those plants are dead.

    Arlington Winter Wheat Variety Trial – Roadside Assessment
    In Field Stand Assessment
    Planting Depth and Tiller Assessment
    Growers and consultants can either reassess in a week or pull plants from the field and place in warm environments. Milk houses and kitchens work perfect. Root regrowth will appear from the crown and will appear as vibrant white roots as shown below.
    Spring Root Regrowth in Winter Wheat

    If plants do not recover our critical threshold for turning over a field is 12 to 15 live plants per square foot. Below this threshold (< 12 plants per square foot) is an automatic replant decision.

  2. In regards to N application timing for winter wheat that decision is pretty darn simple. Research from Dr. Carrie Laboski’s program indicates that the optimal time to apply nitrogen to wheat in WI is green-up regardless of tiller count. For more detailed information check out her  blog article here: Time your spring nitrogen applications to maximize winter wheat yield.
  3. Also remember that wheat grain in itself is only part of the revenue you capture with winter wheat. The price of winter wheat straw remains strong and roughly ~11% less acres of winter wheat were established last fall than the previous year (2017/18). Please consider that revenue stream before any replant decisions are made.
  4. If you decide your wheat crop is not worth keeping (i.e. you can tell your neighbors your planted a planned cover crop last fall) please remember to terminate it a minimum of two weeks before you establish your next cash crop. Click for more details on Cover Crop Do’s and Dont’s

The WSMB Free Soybean Cyst Nematode Testing Program is Back in 2019!

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 (freescntest@mailplus.wisc.edu) or at 608-262-1390.

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 2018 WI Soybean Yield Contest are Announced

The 1st place winner in Division 4, Riley Bros Farms of Darlington, grew Asgrow AG2636 and harvested 99.58 bu/a.  In second place, Venable Farms Inc. of Janesville grew Jung 1243R2X and harvested 93.22 bu/a.  In Division 3, Jim Salentine of Luxemburg harvested 79.32 bu/a with Steyer 1401L and in 2nd place, Oeh My Farms of Abbotsford harvested 77.90 bu/a with Credenz CZ 1028LL.  In Division 2, Custer Farms of Chippewa Falls achieved 72.67 bu/a from Asgrow AG19X8 for first place.  In 2nd place, Adam Majeske of Balsam Lake harvested 56.64 bu/a from Asgrow AG17X8 soybeans.  No entries were submitted for Division 1.

Kreuziger Grain Farms of Juneau was the winner of the Soybean Quality contest with 2,737 pounds of protein plus oil per acre from Pioneer P22T41R2.

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 spconley@wisc.edu