Wisconsin Soybean Marketing Board Continues Free Nematode Testing Program for 2016

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.

Figure 1. WI Counties Confirmed to Have SCN as of 2013.

In 2016, 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.

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 2016 Winter Wheat Crop Stand and Spring Nitrogen Timing

As the snow begins to melt and we finally put the 2015/16 winter behind us, many growers and consultants alike are beginning to venture out to 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 2016 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.

   

   2016 Arlington Winter Wheat Variety Trial - Roadside Assessment

   

   2016 In Field Stand Assessment

   

   2016 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 is an automatic replant.
2. Hot off the press (word press that is)...the N timing decision just got easier.  New 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 new blog article here entitled: Time your spring nitrogen applications to maximize winter wheat yield.
3. Lastly 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 so please consider that revenue stream before any replant decisions are made.

Winners of the 2015 WSA WI Soybean Contest are Announced

The 1^st place winner in Division 4, Bahr Farms Inc. of Belmont, grew Asgrow AG2535 and harvested 89.23 bu/a.  In second place, Riley Bros. Farms of Darlington grew Asgrow AG2433 and harvested 88.85 bu/a.  In Division 3, David and Karen Wilkens of Random Lake won 1^st place with NK S20-T6 Brand at 77.15 bu/a, and in 2^nd place, Echo-Y Inc. of Loganville harvested 75.93 bu/a with NK S20-T6 Brand.  In Division 2, Oeh My Farm of Abbotsford achieved 79.72 bu/a from Asgrow AG1431 for first place.  In 2^nd place, J-Mar Hillside Acres of Luxemburg harvested 74.17 bu/a from Steyer 1140L soybeans.  In Division 1 at 75.67 bu/a was David Lundgren from Amery who planted Croplan R2C1494.  2^nd place winner in Division 1 was Jerry Koser from Almena.  He harvested 60.27 bu/a from DuPont Pioneer 91M10. 

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 608-262-7975 or spconley@wisc.edu

Finalists for the 2015 WI Soybean Yield Contest are Announced

The 2015 growing season proved to be a unique challenge for many WI soybean growers.  Given these widespread challenges however, we again experienced great interest in the 2015 WSA/WSMB Soybean Yield Contest.  The top two entries in each division (in no particular order) were:

Division 4: 

• Jon Riley, Darlington (planted Asgrow AG2433)
• Dale and Kevin Bahr, Belmont (planted Asgrow AG2535)

Division 3:

• David Wilkens, Random Lake (planted NK S20-T6 Brand)
• Derek Yanke, Loganville (planted NK S20-T6 Brand)  

Division 2:

• Jim Salentine, Luxemburg (planted Steyer 1140L) 
• Craig Oehmichen, Abbotsford (planted Asgrow AG1431) 

Division 1: 

• David Lundgren, Amery (planted Cropland R2C1494) 
• Jerry Koser, Almena (planted DuPont Pioneer 91M10)

The final ranking and awards will be presented at the 2016 Corn Soy Expo to be held at the Kalahari Convention Center, Wisconsin Dells on Thursday February 4^th 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 608-262-7975 or spconley@wisc.edu

Start Managing for Fusarium Head Blight Now Before You Plant the 2015/16 Crop

By Shawn P. Conley and Damon Smith

The 2014 and 2015 WI winter wheat crops both endured significant Fusarium head blight (FHB or scab) incidence as well as mycotoxin (vomitoxin) dockage and outright rejections. Here are a few considerations for managing FHB before the 2015/16 crop even goes into the ground.

1.      Crop rotation matters. Data from our long-term rotation studies indicate that wheat following soybean provides the greatest yields. The next best options are wheat following corn silage (6.5% less) then corn for grain (21% less). Wheat following alfalfa or another leguminous crop are also good options, though the N credits following alfalfa may best be served going to corn. Furthermore, background fungal pressure (residue on and in soil) from the FHB fungus will be greater following corn then soybean or another legume, however know that spores that infect your wheat crop can arrive from  outside the field. Please click to see more information on the Top 8 Recommendations for Winter Wheat Establishment in2015.  

2.      Variety selection matters. Data from our 2015 WI Winter Wheat Performance Test shows variable yield and disease performance among the varieties listed. Select those varieties that have both good to excellent FHB resistance and high yield. When evaluating FHB resistance, low numbers for both FHB incidence and severity can be helpful, but the major focus should be placed on FHB incidence (measure of the number of FHB-symptomatic plants in a stand).

3.      Application timing matters. One of the biggest challenges year in and year out is improper fungicide application timing. Our data suggests that on susceptible (Hopewell) or moderately susceptible varieties (Kaskaskia) equal efficacy of the fungicide Prosaro at a rate of 6.5 fl oz/acre can be achieved when applied between Feekes 10.5.1 (anthesis) and 5 days after anthesis. Given the variability of head emergence and anthesis across a landscape it may prove best to wait a few days until the whole field is flowering than to apply too soon.  If the extruded anthers have turned from yellow to white across the whole field then you are likely too late. Remember it roughly takes a wheat head 7 days to completely self-pollinate.

Fusarium head blight incidence ratings for four soft red winter wheat varieties treated with Prosaro SC fungicide at 6.5 fl oz/a at anthesis (Feekes 10.5.1), five days after anthesis, or not treated in Wisconsin in 2015.
	Hopewell (Susceptible)	Kaskaskia (Moderately Susceptible)	Pro 200 (Moderately Resistant)	Sunburst (Moderately Resistant)
Prosaro SC @ 6.5 fl oz/a (Feekes 10.5.1)	9.5b	2b	0.5	4
Prosaro SC @ 6.5 fl oz/a (5 days after Feekes 10.5.1)	7.5b	5.25b	2.75	2.75
Non-treated control	31.25a	17.5a	3	1.5
Pr>F	0.01	0.01	ns	ns
LSD	6.44	6.44	ns	ns

4.      Choose the right fungicide class. Make sure you use the appropriate fungicide product and class to manage FHB. The label for products containing strobilurin active ingredients (FRAC group 11) ends prior to flowering. Late application can actually lead to increased mycotoxin levels. Triazole containing products (FRAC group 3) are recommended for FHB control. For a list of products and efficacy ratings, visit the Field Crops Fungicide Information Page. 

5.      Harvest timing and flash drying. The word on the street is that in 2016 elevators will push growers to harvest early (18% moisture or higher) and subsequently dry grain to mitigate mycotoxin levels. While drying grain to 13% or less moisture is a good storage practice, know this process may kill the pathogen but any mycotoxin levels already in the grain will not dissipate. Vomitoxin is a very stable molecule and IS NOT degraded by heat, freezing, or drying.     

The Nebulous of Non-Nodulating Soybean in 2015 and Again in 2016 and Again in 2017

I have received a deluge (pun intended) of questions regarding the overall lack of soybean nodulation and general pale green coloration of the crop. As a doctor....well Ph.D....I prescribe less rain, sunshine, and call me in two weeks if the problem still exits... Outside of this obvious issue here are the four most common questions I have received and my responses for your consideration.

1. Why is nodulation such a problem this year? Abiotic stress such as low pH (≤ 6.0), saturated or droughty soils and cool soil temperatures can negatively impact nodulation (Valentine et al. 2011). Duzan et al. (2004) reported that root hair deformations (a physiological precursor to rhizobia infection and nodulation) was 64 and 82% of the control when rhizosphere (root zone) temperatures were 59 and 63 degree F when compared to 77 degrees F. This suggests that the cool soil temperatures we have been experiencing have likely limited the infection sites available for nodulation to occur. This effect has likely been exacerbated in no-till or compacted conditions. In short less nodulation sites on the roots means increased likelihood for less nodules.  
2.  I double inoculated my soybeans on virgin ground and my nodule count is really low? First, please refer to #1 above regarding abiotic stress on soybean nodulation. Secondly remember to read and follow the application, compatibility, and planting timing of inoculants. In reading through various inoculant labels today, I saw everything from ‘not tested’ to ‘not compatible to plant within hours to weeks to months of application’. Lastly remember there is a poor correlation between nodule number and N2 fixation, so don't get overly concerned about nodule count; it is nodule efficiency that matters and you can’t measure that by counting. In short, read the labels and make sure everything is compatible and your application and planting window is adequate prior to purchasing the product.
3. How long will soybeans continue to put on new nodules? Dr. Purcell indicated that they can measure very active N2 fixation almost until the end of seedfill (personal communication). Given the normal life span of an active nodule is 4-5 weeks, this would suggest that soybean will continue to put on new nodules (if the environment is conducive and rhizobia are present) until R6 soybean (late pod fill).   
4. Should I apply nitrogen to these poorly nodulating soybeans, and if so, how much? My general answer is no and none. First of all, the application of nitrogen to soybean beyond a "starter" rate (≤~30 pounds) will lead to a rapid and dramatic inhibition of N fixation (Sinclair, 2004). Though it does not appear that the applied nitrogen is directly damaging to the N fixation machinery (nodules), it will reduce or stop fixation. If the soil NO3 levels drop, then N fixation can resume in about a week (Sinclair, 2004). Over-application of N will shut down whatever rhizobia is actively working. Furthermore, our 2014 and 2015 data shows that a soybean plant takes up 3.75 pounds of N in above-ground tissue per bushel of grain. So a 80 bu/a crop removed 302 pounds of N/a. This does not account for below-ground uptake or nitrogen loss and efficiency from the applied nitrogen. In short, that is tough math to get a positive ROI on. 

Literature cited:


Gaspar, A., C. Laboski, S. Naeve, and S.P. Conley. 2017. Dry Matter and Nitrogen Uptake, Partitioning, and Removal across a Wide Range of Soybean Seed Yield Levels. Crop Sci. doi: 10.2135/cropsci2016.05.0322 

Dr. Larry Purcell (personal communication 7/16/15)

H. M. Duzan, X. Zhou, A. Souleimanov and D. L. Smith*. 2004.Perception of Bradyrhizobium japonicum Nod factor by soybean [Glycine max (L.) Merr.] root hairs under abiotic stress conditions. Journal of Experimental Botany, Vol. 55, No. 408, pp. 2641–2646, December 2004 doi:10.1093/jxb/erh26

Sinclair, 2004. Improved Carbon and Nitrogen Assimilation. "In: Soybeans: Improvement, Production, and Uses." Third Edition. Agronomy No.16. Edited by H.R. Boerma and J.E. Specht. 

Valentine, A., V. Benidito, and Y Kang. 2011. Legume Nitrogen Fixation and Soil Abiotic Stress: From Physiological to Genomics and Beyond. Annual Plant Reviews. 42:207-248.