Wednesday, August 6, 2014

2014 WI Soybean Yield Contest Entry Deadline is September 1

Wisconsin soybean growers have until September 1, 2014 to enter the Wisconsin Soybean Yield Contest. Two winners from each of four geographical districts in the state will receive awards (Image 1.).  "Please note the divisional lines were redrawn for 2014 based on a rolling 10 year average yield".   The first place award in each district includes a $1,000 cash prize; second-place honors include a $500 prize. Winners will be selected for having the highest soybean yield based on bushels per acre at 13% moisture. The awards ceremony is scheduled for January 29, 2015 during the Corn/Soy Expo at WI Dells.  

For more detailed information regarding the program and contest rules please visit www.coolbean.info or 2014 Wisconsin Soybean Yield Contest Rules

Entry forms can be found at 2014Wisconsin Soybean Yield Contest Entry Form.

A list of the 2013 winners and a management summary of their practices is also provided. 

For more information please contact Dr. Conley at spconley@wisc.edu. Good luck and have a safe and productive 2014 growing season!


Image 1. Geographic Division Map.


Thursday, July 17, 2014

Think Twice Before Applying Nitrogen to Poorly Nodulated Soybean Fields

Over the last 3 days my phone, email and twitter account has been blowing up with questions surrounding poorly nodulated soybeans and my thoughts regarding applying foliar nitrogen to alleviate those symptoms. I have been reluctant to write this article for two reasons. 
  1. This article will contradict some of my colleagues’ thoughts (Identifying and responding to poor nodulation in soybean) however I would agree with their scenario of applying nitrogen to early-seeded, non-nodulating soybean planted on virgin ground.
  2. I like to speak from data and I don't have a ton of data to speak from 
So with these caveats in mind here is my thought process for asking growers and crop consultants to think twice before applying nitrogen to poorly nodulated soybean fields. 
First lets start with the problem. A record number of soybean acres were planted in 2014. To get those acres both virgin ground as well as long term continuous corn acres were converted to soybean. For the most part (unless someone forgot) those acres did receive a 1x or 2x rate of inoculant. Unfortunately the perfect storm of delayed planting, poor planting conditions, compaction and poor environmental conditions all led to saturated anaerobic soil conditions that limited rhizobia infection.  These poor establishment conditions were then followed by poor early season growth conditions (cool saturated soils) delayed herbicide applications, increased herbicide rates and weed competition that further stressed the plants and limited infection. 

So with all this stress in mind why do I suggest no additional nitrogen?
  1. Once soils dry out and aerobic conditions resume the ethylene stress response in plants quickly dissipates and normal N-fixation can resume. This will lead to nodulation occurring on lateral roots as infection occurs behind the root tip of actively growing root. Furthermore once plant roots resume normal growth they will be able to take advantage of residual and mineralized soil nitrogen which will alleviate the pale green coloration.
  2. Be realistic with your yield potential. Many of the fields in question are late planted, with stunted soybeans and thin stands.  A short soybean crop will require much less N than a big one.  Salvagiotti et al; (2008) indicated in "Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review" that the most likely soybean response to additional nitrogen was in high yield environments. 
  3. Be realistic with your expected yield loss in non-nodulated virgin soil environments. Somehow the idea of a 20 bu yield loss has been floating around the coffee shops. Our most recent data from a virgin soil site in 2010 showed an average +4.6 bu yield gain (range: -0.9 to 9.6 bu depending upon product) from inoculants. The untreated uninoculated check averaged 73.5 bu per acre. Also remember no history of soybean = low soil borne disease pressure and beautiful healthy roots!
  4. What are your 2014 beans marketed at $14.00 or $11.92 and dropping?
  5. What source of nitrogen are you going to apply and what is that cost per pound coupled with application cost and crop damage?
  •  Simple math equation (please insert your number for mine). 70 pounds of urea @ $0.55 per pound  + $8 application cost + $10.26 yield loss from running down soybeans (90 foot applicator = 1.9% on 45 bu $12 beans) = $56.76. At $12 soybeans you would need 4.73 bu to break even. Our average response in 2010 was 4.6 bu.
I know not everyone will agree with my thought process but understand that I am cognizant of the realities of today’s production ag world….high land rent costs coupled with high commodity prices = grower risk aversion. If you do apply nitrogen please leave at least one yield check and be fair to that yield check placement. Given our climate variability this will not be the last time we deal with this question and having data to streamline recommendations in future years makes us all better stewards and producers.

*Reviewed by Dr. Seth Naeve, Extension Soybean Agronomist, University of Minnesota.

Friday, July 11, 2014

Harvest Considerations for a Fusarium Head Blight (Scab) Infected Wheat Fields

Subsection taken from Smith and Conley 2014. Fusarium Head Blight and Other WinterWheat Diseases in Wisconsin, 2014

A survey of the Wisconsin Winter Wheat Variety Trials indicates that some fields will be at risk for dockage or outright rejection of winter wheat grain later this month. Environmental conditions that lead to high risk coupled with susceptible genetics and the grower’s inability to simply get fungicides applied all contributed to this issue.  As we move forward into harvest here are a few point to consider to help mitigate dockage and deoxynivalenol (DON or vomitoxin) risk moving forward.

1.      Scout your fields now to assess risk. Wheat near our Fond du Lac location is maturing making it very difficult to assess the incidence and severity of the infection. Understanding a fields risk will help growers either field blend or avoid highly infected areas so entire loads are not rejected.
2.      Adjust combine settings to blow out lighter seeds and chaff. Salgado et al. 2011 indicated that adjusting a combine’s fan speed between 1,375 and 1,475 rpms and shutter opening to 90 mm (3.5 inches) resulted in the lowest discounts that would have been received at the elevator due to low test weight, % damaged kernels, and level of the mycotoxin deoxynivalenol (DON; vomitoxin) present in the harvested grain.  
3.      Know your elevators inspection and dockage procedure (each elevator can have a different procedure).
4.      Scabby kernels does not necessarily mean high DON levels and vice versa.
5.      DON can be present in the straw so there is concern regarding feeding or using scab infected wheat straw.  DO NOT use straw for bedding or feed from fields with high levels of scab (Cowger and Arellano, 2013).
6.      Do not save seed from a scab-infected field. Fusarium graminearum can be transmitted via seed. Infected seeds will have decreased growth and tillering capacity as well as increased risk for winterkill.
7.      Do not store grain from fields with high levels of scab.  DON and other mycotoxins can continue to increase in stored grain.
8.      For more information on Fusarium head blight, visit this information page: http://fyi.uwex.edu/fieldcroppathology/fusarium-head-blight-scab-of-wheat/

References
Cowger, C., and Arellano, C. 2013. Fusarium graminearum infection and deoxynivalenol concentrations during development of wheat spikes. Phytopathology 103:460-471.

Salgado, J. D., Wallhead, M., Madden, L. V., and Paul, P. A. 2011. Grain harvesting strategies to minimize grain quality losses due to Fusarium head blight in wheat. Plant Dis. 95:1448-1457.

Friday, June 27, 2014

Bloomin Beans, Glyphosate, and Wheel Track Damage

The WI soybean crop ranges anywhere from just planted (JP) to beginning flower (R1). 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 glyphosate applications in our early planted soybean is quickly closing. Glyphosate labels indicate that applications can be made through R2 or full flower. The R3 growth stage begins when one of the four top nodes with a fully developed leaf has a 3/16 inch long pod. Applications made after the R3 stage begins are off-label applications. 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.

Tuesday, May 27, 2014

Delayed Planting: Top Three Considerations for Switching Corn Acres to Soybean

A tremendous number of corn and soybean acres have been planted over the past 10 days; however C, NC, and NE WI continue to get hammered for the second year in a row with awful planting weather.  It seems like those growers are constantly 1/2 day away from the soil being fit to go. Over the past two weeks we have  discussed maturity switch dates for corn grain, corn silage and soybean cultivars. What about switching corn ground to soybean.

1. Check your herbicide label. Several burn-down or early pre-plant programs have labels for both crops. However tankmix partners or rates may differ between the two. Maker sure you verify rates, timings, and plant back restrictions before you make the switch. Even with the intense rainfall we have experienced don't bank on these products being gone.   

2. Fall applied anhydrous or spring applied urea. How much N is too much to not even consider the switch?  Biologically I don't think that number really exists. Economically that number is a moving target given yield penalty, corn drying costs, etc. What I can surmise and you would likely agree with is that over the last 4 weeks the amount of N readily available to the late planted corn crop or in this case the soybean crop has declined, though some N is still readily in the soil profile. We were somewhat prepared for this question a year ago given the likelihood of residual N following the 2012 drought stricken corn. In that article I stated:
In excess situations soybean will generally utilize the background nitrogen prior to initiating maximum N fixation. This may lead to luxurious early season growth, which in fields with a history of white mold, may cause problems if weather conditions are conducive. High soil N reserves may also lead to increased lodging. In either case, manage your soybean crop accordingly to minimize risk of white mold or lodging. This can be accomplished through variety selection (e.g. white mold tolerance, short statured soybean cultivars or good lodging tolerance), decreasing seeding rates, and proper scouting to time fungicide applications if needed.    
The only change I would make to this paragraph would be to increase seeding rates to compensate for delayed planting. Remember when I wrote this article in 2013 I was under the assumption that soybean would be planted the first week in May not the first week in June.

3. Should I use an inoculant even when excess N is present? The simple answer is yes and here is why....excess N limits N fixation (Lit review excerpt quoted with permission from Eric Wilson; M.S. Thesis; Shaun Casteel Adviser; Purdue University)
Nitrate uptake of soybean plants did not appear to directly damage the BNF capacity (Streeter, 1985; Arrese-Igor et. al, 1997). Streeter (1985) concluded that carbohydrate deprivation and nitrate toxicity did not inhibit BNF. It is hypothesized that additional nitrate increased the oxygen diffusion barrier of the nodule, which limited oxygen supply and restricted nitrogenase activity and nodule respiration (Vessey and Waterer, 1992). This hypothesis was supported by Arrese-Igor et al., 1997. However, additional oxygen supplied to the nodules did not markedly increase BNF (Heckmann et al., 1989; Serraj et al., 1992).
Literature cited:

Arrese-Igor, C., F.R. Minchin, A.J. Gordon, and A.K. Nath. 1997. Possible causes of the physiological decline in soybean nitrogen fixation in the presence of nitrate. Journal of Experimental Botany 48:905-913.
Heckmann, M.O., J.J. Drevon, P. Saglio, and L. Salsac. 1989. Effect of oxygen and malate on NO3- inhibition of nitrogenase in soybean nodules. Plant Physiology 90:224-229.
Serraj, R., J.J. Drevon, M. Obaton, and A.Vidal. 1992. Variation in nitrate tolerance of nitrogen-fixation in soybean glycine-max. - Bradyrhizobium symbiosis. Journal of Plant Physiology 140:366-371.
Streeter, J.G. 1985. Nitrate inhibition of legume nodule growth and activity .2. short-term studies with high nitrate supply. Plant Physiology 77:325-328.
Vessey, J.K., C.D. Raper, and L.T. Henry. 1990. Cyclic variations in nitrogen uptake rate in soybean plants - uptake during reproductive growth. Journal of Experimental Botany 41:1579-1584.

Friday, May 16, 2014

Recent Cold Temperatures will have Little Impact on WI Winter Wheat Crop

With cold temperatures predicted over the next few days (May 15-17) there are some questions regarding the potential impact on this year’s winter wheat crop. Based on the predicted temperatures reported, widespread significant crop injury is unlikely. The winter wheat crop is several weeks behind "normal" and remains in the tiller (Feekes 2) to jointing (Feekes 6) growth stages. At these growth stages the wheat crop can withstand temperature down to 24 degree F for up to 2 hours before crop injury occurs (Table 1).  For more detailed information I have attached a link to a publication entitled Spring Freeze Injury to Kansas Wheat.  For ease I have also removed a table from that publication to stress the importance of growth stage on damage potential  (Table 1).

Lastly, growers may also be questioning the impact of temporary flooding within fields. Though crop injury from this flooding may occur that damage will likely be limited due to cool temperatures and slowed crop respiration. Any crop injury that does occur will directly be related to the duration of the flooding event.


Table 1.  Wheat Resistance to Freeze Injury (From: Spring Freeze Injury to Kansas Wheat)

Tuesday, April 15, 2014

Top 5 Recommendations for Soybean Establishment and Yield

I awoke this morning to the gleeful announcement from my two year old yelling at the top of her lungs "Dad....snow....outside''. I feigned excitement only because I know we are still missing 75 entries for our soybean variety test program (hint hint to those that are delinquent) and suboptimal soil temperatures (Figure 1).
Hobolinkplot_1002666-1_week
Figure 1. Soil temperature (2") at Arlington WI April 9-15, 2014.
As past experience has taught many of us that live in the "frozen tundra", a WI spring can appear rapidly so here are a few thoughts to mull over before we all get busy and throw recommendations out the window to get those crops in the ground.

1. Planting date matters for northern soybean growers. Dr. Specht et al. from UNL did a very good job discussing "Why planting soybean early improves yield potential".  Furthermore, our recent planting date data is also very supportive of early planting.  Not only have we seen a synergistic yield response with today's genetics to early planting, we also average ~0.36 bu per day cost to delaying planting past the first week of May (please see Figure 2. below).   
Figure 2. Soybean yield response to planting date at Arlington and Hancock WI 2012-13.
2. Use a fungicide and insecticide seed treatment. Given today's seed input costs and commodity price our data suggests reduced economic risk and increased profitability utilizing these inputs.

3. Plant your soybean seed 1" deep. I know I know MSU just came out with new information regarding soybean planting depth, but I am not completely sold on planting early soybean at 1.75 inches in Wisconsin. If it is June 5th, soil temps are 72 degree F, and I am planting to moisture due to drought conditions and no rain in the forecast then maybe I could be convinced.   

4. In short....if rotating with corn no tillage is required!

5. Last but certainly not least, invest in a residual herbicide program for your soybean crop. Not only is it an effective tool for herbicide resistance management (remember we have two confirmed (one suspect) glyphosate resistant weed populations in WI) it also widens the application window for glyphosate and it often provides growers with a positive ROI.