ISSUE #510

510 - Spray Drift Management


Weed control has long been the number one production problem for sugarbeet growers in Minnesota and North Dakota. Use of Roundup Ready® varieties and Powermax or WeatherMax Roundup® formulations will make weed control much easier than it has ever been. However with this ease of weed control comes the risk of spray drift to nearby non Roundup Ready crops such as small grains, edible beans, potato or other crops. Growers have a number of options available to minimize the potential for drift development that need to be considered.

Strategies for Drift Management

  • Monitor wind speed and direction - go to NDAWN weather website from NDSU or call these stations directly
Ada 218-784-2600 Warren 218-745-6095
Eldred 218-857-3386 Cavalier 701-265-8479
Forest River 701-284-6847 Fargo 701-231-8540
Grafton 701-352-0987 Galesburg 701-488-2734
Hillsboro 701-436-3945 Grand Forks 701-722-0122
Leonard 701-645-9037 Humboldt 218-379-0027
Perley 218-861-6101 Mayville 701-786-2042
Sabin 218-789-7222 Prosper 701-347-4864
St. Thomas 701-257-6436 Stephen 218-478-2750
Wahpeton 701-642-8661    
  • Drift risk increases greatly as wind speed increases especially above 10 mph.
  • Nozzle selection - choose spray nozzles that produce larger droplets, choose nozzles with wide angle patterns that allow boom height to be lowered
  • Spray pressure - lower pressures produce larger spray droplets
  • Spray volume - use higher volumes to increase droplet size and reduce drift
  • Boom height - higher boom heights above target weeds or the soil surface increase drift potential
  • Avoid inversion conditions - low winds to almost calm conditions with cool air near the soil trapped below a layer of warm air can allow drift to travel great distances (watch dust movement from gravel roads on these calm mornings)
  • Use drift retardant agents to increase spray droplet size and reduce drift
  • High temperatures increase evaporation from spray droplets reducing droplet size and potentially increasing drift risk
  • Low humidity also increases evaporation, reducing droplet size and increasing drift risk
  • Equipment selection - spray air equipment using high air volumes can result in small droplets and excessive drift. Carefully set up your spray air units
  • Shields - spray shields, while cumbersome to deal with, greatly reduce drift
  • Herbicide volatility - Roundup is not volatile and will not drift as a vapor, it drifts only by particle drift

Table 1. Influence of droplet size on potential distance of drift.

Droplet Diameter (microns)Type of DropletTime Required to Fall 10 FeetLateral Distance Droplets Travel in Falling 10 feet in a 3 MPH Wind
5 Fog 66 minutes 3 miles
20 Very fine spray 4.2 minutes 1,100 feet
100 Fine spray 10 seconds 44 feet
240 Medium spray 6 seconds 28 feet
400 Coarse spray 2 seconds 8.5 feet
1,000 Fine rain 1 second 4.7 feet

Source: Klingman (9), Potts (1.1) and Akesson and Yates (2)

P Fertilizer 2009 - Its time to start thinking about how to supply P to your 2009 crop. Use of 3 gpa of 10-34-0 versus 11-52-0 would result in over $20/acre savings.

Dr. Jeff Stachler Named Extension Sugarbeet Specialist for North Dakota State University and the University of Minnesota

510.dr .jeffDr. Stachler was employed by the Ohio State University for a little over 12.5 years as a Weed Science Extension Program Specialist in the Horticulture and Crop Sciences Department. He was responsible for field and greenhouse research on special weed problems in corn, soybeans and other crops, extension education, classroom education, and was coach of the Weed Science team that placed 1st for 7 consecutive years at the North Central Weed Science Societies Summer Contest. Please welcome him to the Red River Valley.

Dr. Stachler was raised in Rossburg, Ohio on a diversified livestock and crop farm, attended Ohio State University with a major in Agronomy in 1992. He received his Master of Science at Michigan State University with specialization in Weed Science in 1995. In 2008 he received his PhD at Ohio State University with specialization in Weed Science; Dissertation title - Characterization and Management of Glyphosate-Resistant Giant Ragweed and Horseweed.

Replant Date Changed

The new 5-Year Agreement requires growers to replant sugarbeets until June 10. Previous agreements required replanting only through June 1.

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