Production Blog
Pam Smith DTN\Progressive Farmer Crops Technology Editor

Thursday 07/10/14

Sprayer Tracks Cut Yield

DECATUR, Ill. (DTN) -- Entering a field to take photos or pull yield samples generally involves what amounts to gymnastics on my behalf -- especially as the soybean crop starts to take off. I can't stand to step on the crop or harm it in any way.

Sprayer tracks beyond certain growth stages can result in soybean yield loss. (DTN photo by Pamela Smith)

While my steps may not result in much yield loss, it turns out sprayers can and do take their toll. Research by agricultural engineer Mark Hanna at Iowa State University indicates sprayer wheel traffic from first flower (R1) through harvest can damage soybean plants and reduce yield.

University of Wisconsin soybean specialist Shawn Conley has found that an adequate soybean stand (more than 100,000 plants per acre) planted in late April through 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," said Conley.

"Regardless of stand, plants could not compensate for wheel tracks made at R3 (early pod development) or R5 (early seed development)," Conley reported. In Conley's trials, yield losses averaged 2.5%, 1.9% and 1.3% when sprayer boom widths (distance between wheel track passes) measured 60, 90 and 120 feet, respectively. Multiple trips along the same wheel tracks did not increase yield loss over the first trip.

Wet conditions have delayed postemergence herbicide applications this year, so sprayer tracks are going to happen. With resistance to herbicides swirling and aggressive weeds such as Palmer amaranth looming, letting weeds go to seed is not a good option.

In addition, fungicide applications are generally in the R3 timeframe. Conley said they did not see an economic response to fungicides in his studies. However, fungicides in the presence of disease are another matter and this year's wet conditions favor disease pressure. University of Illinois plant physiologist Fred Below gives fungicides and insecticide applications a 3.6 bushels per acre yield credit when other high yield practices are in place. Obviously, pest problems need to be addressed if they are challenging yield.

Just watch your step -- all these maybes need to be weighed with the potential losses of running the sprayer through a standing crop.

For more reading on this topic go to:

http://thesoyreport.blogspot.com/…

https://www.extension.purdue.edu/…

Pam Smith can be reached at pam.smith@dtn.com

Follow Pam Smith on Twitter @PamSmithDTN

(CZ)

Posted at 3:46PM CDT 07/10/14 by Pam Smith
Post a Blog Comment:
Your Comment:
DTN reserves the right to delete comments posted to any of our blogs and forums, for reasons including profanity, libel, irrelevant personal attacks and advertisements.
Blog Home Pages
September  2014
S M T W T F S
   1 2 3 4 5 6
7 8 9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30            
Subscribe to Production Blog RSS
Recent Blog Posts
  • Corn Is Still Wet, But Clock Ticks
  • Get In the Mode
  • Filling Out a Big Crop
  • The Trouble With Time
  • Yield Countdown
  • Four-Leaf Soy Surprise
  • Sprayer Tracks Cut Yield
  • Wild Weather Woes
  • Evaluate Soybean Emergence
  • May Bee Mystery
  • Droning On In the Cab
  • Corn Takes Off
  • Tend Your Traits
  • War of the Words
  • Weed Patch Lessons; Diversity is the Key
  • Rotate Your Thinking
  • Caterpillar Droppings
  • Cold Stress Test
  • Negotiate the Bt Maze
  • Ag Blessings Abound