Planting Date and Maturity Group Considerations Moving into a Potentially Early Spring 2017.

Article written by Dr. Adam Gaspar and Dr. Shawn P. Conley

Early May planting in Wisconsin has been documented to increase yield due to increased light interception (Gaspar and Conley, 2015).  Earlier planting dates are able to increase light interception in two ways, which are both demonstrated in Figure 1. First, the reproductive growth period between R1-R6 occurs during longer days with the May 1^st (Green line) compared to June 1^st (Orange line) planting date.  Secondly, the time spent in the R1-R6 growth stages is increased with the earlier planting date. As Figure one shows, the May 1^st planting date spent ~60 days from R1-R6 compared ~45 days for the June 1^st planting date.  Therefore, early plated soybeans experience both longer duration in reproductive growth (more days) and reproductive growth during the longest days of the summer. 

Figure 1. Blue lines represent day length at various latitudes. Most WI soybeans are grown between 43 and 45 degrees latitude. The vertical lines represent the time spent from R1 through R6 for May 1^st (Green Lines) and June 1^st (Orange Lines) planting dates. WI soybeans are mainly grown between 43 and 45 degrees latitude.

Yet, in some instances (weather or logistical problems) planting can be delayed or replanting may be needed. Therefore, investigating the effect of different MG’s at multiple planting dates across the state would be useful.  Thus, DuPont Pioneer and the Wisconsin Soybean Marketing Board funded a 3-year study to examine proper MG selection at 5 different planting dates across the state to maximize yield.  So let’s look at the 2014-2016 data.

Trials were conducted at Arlington, Hancock, and Spooner, WI.  The five planting dates at each location were planting roughly on: (1) May 1^th, (2) May 20^th, (3) June 1^st, (4) June 10^th, and (5) June 20^th.  Planting after June 20^th is generally not recommended in WI.  Two varieties within each realistic MG from a 2.5 all the way down to a 00.5 were tested depending upon the location and planting date and are displayed in Table 1.  

Table 1. Maturity Group’s tested within each location and planting date.
Planting Date		Arlington	Hancock	Spooner
1 (May 1th)		2.5, 2.0, 1.5	2.5, 2.0, 1.5	1.5, 1.0, 0.5
2 (May 20th)		2.5, 2.0, 1.5	2.5, 2.0, 1.5	1.5, 1.0, 0.5
3 (June 1st)		2.0, 1.5, 1.0	2.0, 1.5, 1.0	1.0, 0.5, 0.0
4 (June 10th)		2.0, 1.5, 1.0	2.0, 1.5, 1.0	1.0, 0.5, 0.0
5 (June 20th)		1.5, 1.0, 0.5	1.5, 1.0, 0.5	0.5, 0.0, 00.5

We will start with the easy and redundant part, get your soybeans in the ground ASAP to maximize yield.  This is very evident again in this trial as shown in Figure 2 and 3. If the soil is fit, soil temps are near 50 ˚F, and the forecast is favorable….. get that soybean planter rolling! As you would expect we found some very interesting synergies between early planting and longer MG’s.  Figure 2 contains MG 1.5 soybeans which at the May 1^st planting date only achieved ~85% of max yield.  Figure 3 contains the longest maturing soybean varieties (>1.5) for each location where soybeans reached 99% of max yield, with May 1^st planting.  Furthermore, as planting is delayed, the earlier MG bean’s (Figure 2) do not show a quick and dramatic yield decline compared to the later maturing beans (Figure 3).  Therefore, those that may have not experienced yield loss from delayed planting are likely planting varieties from a MG too short for their respective area.  Clear yield synergies are demonstrated in Figure 2 and 3 from planting early and using a longer MG soybean variety.  Both management practices add no additional cost, meaning any yield increase is direct profit. 

Figure 2. Yield of planting date from May 1^st (120) into June of 1.5MG soybean varieties.

Figure 3. Yield of planting date from May 1^st (120) into June for longest maturing soybean varieties at each location.

 Table 2. Effect of Maturity Group on Yield tested within each location and planting date, during 2014, 2015, and 2016

Planting Date		Arlington	Hancock	Spooner
1 (May 1th)		2.5	2.5	1.5
2 (May 20th)		2.5	2.5	1.5
3 (May 30th)		2.0	2.0	1.0
4 (June 10th)		2.0	2.0	0.5
5 (June 20th)		1.5	1.5	0.5
The numerically highest yielding MG for each planting date and location.  MG that are bold and colored red were significantly higher at the  P ≤ 0.10

Table 2 agrees with the conclusion from Figures 2 and 3, that early planting and longer maturity groups maximize yield. However, due to no significant MG effect at the Spooner location, the synergy of early planting and longer MG’s, may not be as consistent in Northern WI where the growing season is condensed. Planting date 5 at Arlington and Hancock was not significant for MG effects, but the longest MG planted there still yielded the highest numerically.  This was also the case at Spooner, but the 0.5 MG significantly out yielded the 0.0 and ultra-early 00.5 MG varieties.   

These results suggest planting a portion of your acres to slightly longer MG than normal within May can result in greater yields with no additional dollars spent.  In addition, when planting is delayed into June, switching to a variety much more than 0.5 MG earlier than a full season variety (2.5 MG) may limit yield potential.  However, if planting is delayed until mid to late June or more likely replanting is needed, a variety that is at least a full MG earlier should be considered to avoid fall frost damage.

In conclusion, early planting is critical for higher yields through increased light interception, and can be further maximized by planting longer MG’s. However, variety selection heavily based upon the MG is not the “silver bullet” for increasing yields. Yet, it does provide a strong “potential” for higher yields with no additional dollars spent, especially in early planting situations. Therefore, growers should give consideration to MG when selecting varieties, but past local and regional performance, disease package, scn-resistance, etc. should also strongly be considered.

References:

Gaspar, A.P. and S.P. Conley. 2015. Responses of canopy reflectance, light interception, and soybean seed yield to replanting suboptimal stands. Crop Sci. 55:377-385.

Wisconsin Soybean Marketing Board Announces Changes to the 2017 Free Nematode Testing Program

Four out of every five animals on earth today is a nematode so it is not surprising that agricultural fields are home to many nematode species. Fortunately, most nematodes are beneficial to crop growth and soil health because their activities help decompose crop residues and cycle nitrogen and other nutrients. Pest nematodes do not threaten yield if their numbers remain low. The key to avoiding population explosions of nematode pests is to be proactive – know what the situation is and take appropriate measures when nematode numbers indicate a problem is brewing. 

The WSMB sponsors free nematode testing to help producers stay ahead of the most important nematode pest of soybean, the soybean cyst nematode (SCN) (Figure 1). 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 2017, the WSMB is again offering the expanded 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.


In 2017 the WSMB will use PestPros Inc. as the diagnostic lab for nematode quantification. Please discard all old kits and order now ones at the email address below.  

Free soil sample test kits are available now and can be requested at (freescntest@mailplus.wisc.edu).
 

For more information on SCN testing and management practices to help reduce the losses from this pest, please contact: Shawn Conley: spconley@wisc.edu; 608-262-7975 or visit www.coolbean.info. 

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.

Factors to Consider While Assessing Your 2017 Winter Wheat Crop Stand and Spring Nitrogen Timing

As we begin to contemplate spring and the 2017 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 2017 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.
   

   

   2017 Arlington Winter Wheat Variety Trial - Roadside Assessment

   
   

   

   2017 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 20% less acres of winter wheat were established last fall than the previous year (2015/16). 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