Monday, July 29, 2013

WI Soybean Yield Contest Entry Deadline Extended to (9/1/13)

Delayed planting coupled with wet early season growing conditions across much of Wisconsin has dampened grower enthusiasm to enter the 2013 WI Soybean Yield Contest. Excellent growing conditions over the last several weeks has renewed grower interest. To facilitate this interest we are extending the entry due date to September 1st to enter the contest.  Below please find links for entry forms and rules. Good Luck!!!

Thursday, July 11, 2013

High Value Straw and Weedy Wheat…What Do I Do?

Wet fields made spring weed control difficult to impossible in many winter wheat fields, and prolonged wet conditions have encouraged prolific weed growth from large competitive broadleaf weeds like giant ragweed and lambsquarters.  As we approach harvest in southern WI (week of August 21st) growers simply have limited herbicide options for preharvest weed management:
1. 2,4-D products. There is a 7 day pre-harvest interval with this product. The downside of 2,4-D is you are NOT allowed to feed treated straw to animals. That restriction alone probably leaves just one option…. 
2. Glyphosate products. There is also a 7 day pre-harvest interval with this product, and it can NOT be applied until the grain is at the hard dough stage (30% moisture or less).  Grain treated with glyphosate at this growth stage should not be used for seed as germination can be significantly lowered. 
Some benefits to applying preharvest glyphosate may include desiccation of green weedy plants to enable an easier combine harvest and quicken the ability to bale straw following the grain harvest.  However, drawbacks include a narrow window of application timing ahead of harvest, wheel tracks (if ground applied) will reduce grain yields, and moreover many of the weeds like giant ragweed and lambsquarters will be large and difficult to control.  Thus, consider a preharvest glyphosate application as a last resort because partial control of large weeds will greatly increase selection pressure for glyphosate resistance.  We already have glyphosate-resistant giant ragweed in southern WI , and other broadleaf weeds continue to be a concern. 

Shawn Conley and Vince Davis

Monday, July 1, 2013

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.

Mike Bertram a WSA board member reminded me to add the category almost planted (AP).  That's the treated seed that's in the drill that will hopefully gets planted if the field dries out this week.  It might end up as forage.
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. 

Deadline Approaching (8/1/13) for Entering the 2013 Wisconsin Soybean Association Yield Contest

Late planting and overall wet conditions across many areas in WI have dampened (unfortunate but true pun) the excitement of last year’s yield contest where the 1st place winner in Division 4, Bahr Farms of Belmont grew Trelay 24RR19 and harvested 82.6 bu/a. In Division 3, RnK DeVoe Farms of Monroe won 1stplace with Pioneer 93Y43 at 75.2 bu/a while Division 2 winner, Jerry Koser of Almena achieved 73.7 bu/a from Pioneer 91M10. Last but not least Kloos Acres from Stratford took Division 1 at 61.2 bu/a planting Pioneer 91Y30. If we do get into a normal rainfall pattern there is still significant yield to be gained so as a friendly reminder:
  • The deadline to enter the 2013 WI Soybean Yield Contest is 8/1/13. 
  • The objective of this contest is to encourage the development of new and innovative management practices and to show the importance of using sound cultural practices in WI soybean production. 
  • Districts are based on long term county soybean yield averages (Image 1 below). 
  • For more information please see the contest brochure or review contest rules and entry form.