Eight Keys To Managing Spray Drift

Spray DriftIf you ask any custom applicator what their top five concerns are when doing their jobs, chances are managing spray drift will be mentioned. The consequences of this are potentially severe, with regulatory fines and/or customer damage claims easily costing several thousands of dollars (if not more).

In fact, according to Bruce Senst, director of Agrisolutions adjuvants for WinField Solutions, Shoreview, MN, the potential for spray drift keeps many segments of the agricultural community awake at night. “There are plenty of things that worry your average grower or ag retailer,” says Senst. “But when it comes right down to it, everyone is concerned as all get out about spray drift and its impact on their livelihood.”

Complicating the spray drift issue in recent years is the increasing spread of herbicide-resistant weeds. Based upon the best estimates, approximately 60 million acres of U.S. farmland were infested with herbicide-resistant weeds in 2012, with portions of the Mid-South region particularly hard hit. This has increased the likelihood that applicators will need to use several different crop protection products than they did in previous years.

“Let’s face it — we are coming out of an era where you could use one product technology, glyphosate, to manage most of your application needs,” says Damon Palmer, U.S. commercial leader for the Enlist Weed Control System at Dow AgroSciences, Indianapolis, IN. “But now, to achieve this same level of control, applicators are having to mix other crop protection products into their programs, and that has sparked a lot of questions about how do you manage spray drift when you are using multiple herbicides?”

Furthermore, several crop protection manufacturers such as Dow AgroSciences and Monsanto Co., St. Louis, MO, are readying new herbicide-resistant cropping systems for the marketplace in the coming years. This has the potential to see increased application usage for products such as 2,4-D and dicamba, which in turn, will increase the pressure on applicators to more accurately manage spray drift.

Best Equipment Practices

With these factors in mind, CropLife® magazine spoke with Dr. Robert Wolf, Wolf Consulting & Research, LLC, Mahomet, IL. The past few years, Wolf has spent much of his time conducting the On Target Application Academy (with cooperation from TeeJet Technologies and BASF).

“In my training, I have a list of drift management strategies that I work from,” says Wolf. “I probably trained nearly 3,000-plus applicators in 2012.” In essence, he adds, there are eight best management practices applicators should follow to manage spray drift.

No. 1: Nozzle Selection. “This is the strategy that has been used for years to reduce spray drift,” says Wolf. “However, with today’s nozzle options, there are many more choices from multiple nozzle manufacturers that applicators have. The challenge is how best to set the sprayer parameters — basically speed and pressure — so that while minimizing drift crop protection efficacy is not sacrificed. In recent years, that has been an issue.”

Michelle Vigna, assistant launch manager, Roundup Ready Xtend System for Monsanto, agrees that nozzle selection is one of the keys to preventing spray drift. “Here at Monsanto as we introduce the Roundup Ready Xtend system, we are focusing a lot of attention on proper nozzle selection,” says Vigna. “For our users to achieve the best on-target application, we recommend they use air induction nozzles.”

No. 2: Use lower pressures. This is another widely held method for managing spray drift. However, according to Wolf, this practice might require some adjustment to be effective in today’s application world.

“Forever, the advice to applicators for reducing spray drift was to ‘use a lower pressure,’ which result in larger droplets,” he says. “This was the No. 1 educational point for drift minimization.”

Some of these recommendations have changed, however, as nozzle technology has improved. “Now we have nozzles designed to reduce drift while at the same time doing so at higher pressure,” says Wolf. “The higher pressure is needed to help produce a smaller droplet size increasing the coverage potential on the targeted pest — typically a herbicide on a weed. This fact was not really known when the designs were first introduced.”

As Wolf explains, the design of drift reducing nozzles is to create a pressure drop and, in some cases, introduce air via a Venturi into the mix. Both of these will produce larger droplets.

“When using a drift reducing nozzle at a low pressure, i.e., 30 to 40 psi, it is quite possible, because of the design, that the outlet pressure has been reduced in a ratio of 3:1 or 4:1,” says Wolf. “This can result in an exit psi of 10 to 20 psi. That is too low to maintain a quality pattern or to create droplets for adequate coverage. Thus, the recommendation is to use these Venturi designs — commonly referred to air induction — at pressures ranging from 50 to 80 or higher psi. Even at that high pressure, the amount of drift is less than previous designs at lower pressures.”

No. 3: Increasing flow rates. This is been done by applicators to achieve higher application volumes. According to Wolf, this has been a common practice to reduce spray drift for years. “In general, bigger orifices produce larger droplets,” he says.

However, geography can impact how this practice plays out to manage drift for some applicators. “My years in Kansas provide a different perspective on this issue,” says Wolf. “For the most part, applicators in the Plains states tend to use less water in the spray mix. This is probably a result of the environment . . . less water available for most all things in agriculture and wanting to spray more acres on a tank load of mix. The problem is that when using less water, a smaller-sized nozzle is needed, resulting in smaller, more drift-prone spray droplets. Combine that with modern sprayers capable of higher application speeds — translated to higher pressures — and more drift is possible.”

No. 4: Lower the boom height. Again, cautions Wolf, what applicators have traditionally done in this area may not still be the best way to manage spray drift. “Today, some applicators do not understand that the height of the boom above the target is based on nozzle spacing and overlap requirements to achieve a uniform application across the boom,” he says. “The ‘rule of thumb’ for boom height in the industry is 1:1. That would mean a 20-inch nozzle spacing would require a 20-inch boom height above the target, either the soil in a pre-emergence application or the weed or crop canopy in a foliar scenario.”

Instead, Wolf recommends applicators get their boom heights down to 24 inches. “In my opinion, that will go a long way toward reducing drift,” he says. “I have a slogan for this — lowering the boom on spray drift.”

Other Considerations

No. 5: Watch application speeds. “Most all applicators are using electronics to apply crop protection products,” he points out. “The purpose of a rate controller is to make the application volume uniform. What most do not realize is the speed change will also affect the spray pressure. Higher speeds require higher pressure to deliver the correct volume; lower speeds the opposite. Thus, as applicators are making speed changes, they are impacting the droplet size.”

In his training exercises, Wolf cites this example to illustrate this point: An applicator has set the sprayer up to use a #4 nozzle going 12 mph at 40 psi to deliver 10 gallons per acre. A storm is brewing in the West, so the applicator decides to speed up to 15 mph. A 3 mph speed increase will require the pressure to increase to over 60 psi in order to deliver the same volume through the #4 nozzle. As the storm gets closer, they speed up a second time to 18 mph. Now the pressure will need to be 90 psi to deliver the same volume, which obviously increases the potential for spray drift to occur.

“My educational point is to drive at the speed you calibrated for,” he says. “Also, the rule applicators should remember is that to double the flow from a given orifice size, they will need to increase the pressure four-fold. As an example: If the applicator is going 8 mph at 30 psi and changes to 16 mph, this will cause the pressure to increase to 120 psi.”

No. 6: Avoid adverse weather conditions. According to Wolf, these would include high winds, calm air or inversions. “This is an area that applicators have no control over,” he says. “But the best option is still to choose not to spray when environmental conditions are not favorable.”

No. 7: Use buffer zones. As Wolf points out, the increase in different herbicides, coupled with label requirements, in the near future will make these more important for applicators to achieve proper on-target work. However, size could be an issue.

“The size of the buffer zone will be the problem,” he says. “The concern today is that ground applicators might not consider not spraying next to a sensitive area by leaving a buffer zone. Instead, they might choose to come back on a day when the wind is blowing away from the sensitivity to spray.”

No. 8: Consider other technologies to reduce drift potential. According to Wolf, this could include the use of shields, air-assist or pulse-width modulation or drift reduction additives such as adjuvants.

In summation, Wolf reminds applicators that all of these practices are good at reducing the potential for spray drift, but only if they aren’t chosen selectively. “A good drift management plan will include multiple strategies,” he concludes. “One item from this list will not be sufficient alone. One practice alone does not make for a good plan.”

Topics: , ,

Leave a Reply

Management Stories

ManagementMACA 2014: The State Of The Agricultural Industry, And Then Some
October 9, 2014
The trade association’s annual gathering featured speakers from across agriculture and beyond. Read More
StewardshipA Multi-Layered Approach To Water Quality
October 6, 2014
Illinois event highlights research and technology designed to better monitor and improve water quality — and the benefits of cooperative, coordinated effort. Read More
StewardshipMichigan Agriculture Leaders On Toledo Water Ban: We Want To Be Part Of The Conversation
August 8, 2014
Leaders of Michigan agricultural organizations said Thursday that the government should not have a “knee-jerk reaction” based on last weekend’s water ban in Toledo due to fertilizer run-off in Lake Erie. Read More
ManagementRussia Bans U.S. And EU Ag Product Imports In Ukraine Sanctions Battle
August 7, 2014
Russian President Vladimir Putin has banned the import of agricultural goods from countries that have imposed sanctions on Russia. Read More

Trending Articles

HerbicidesAdjusting To The New Reality Of Weed Control
November 4, 2014
Even with new cropping systems being readied for market introductions, weed control will remain a challenge for many. Read More
StewardshipResponsibleAg Begins Auditor Training
October 31, 2014
ResponsibleAg auditor training is now underway at the Ford B. West Center for Responsible Agriculture in Owensboro, KY. Read More
InsecticidesNew Research Study Shows The Value Of Neonics
October 29, 2014
The study evaluated seed treatment, soil and foliar uses of neonicotinoid insecticides in the U.S. and Canada. Read More
Crop InputsPlatform Specialty Products To Acquire Arysta LifeScience
October 20, 2014
Once the acquisition is complete, Platform Specialty Products will combine Arysta LifeScience with previously acquired companies Agriphar and Chemtura Crop Solutions. Read More
Seed/BiotechMonsanto Offers New Support For Ferguson, Area Communities
October 8, 2014
Monsanto Co. has committed $1 million in new support for several collaborative efforts in Ferguson, MO, and surrounding communities in North St. Louis County. Read More
Seed/BiotechUnapproved Genetically Modified Wheat Found In Montana
October 3, 2014
USDA reports that one year after discovery of Monsanto's unapproved wheat in a single Oregon field disrupted U.S. wheat export sales, the GMO wheat has again been found in Montana. Read More

Latest News

soybean field
Crop InputsABM Patents Microbial R&D Technique
November 25, 2014
Focused Microbial Diversity (FMD) is a newly patented technique employed by Advanced Biological Marketing (ABM) to research and develop microbials that will be used in ABM products Read More
Crop InputsStorage Options Help Grain Growers Go To Market
November 24, 2014
While on-farm storage in a traditional upright storage bin is one possibility for storing grain, it may not be for everyone. Read More
Eric SfiligojGiving Thanks For Another Great Year
November 24, 2014
As Thanksgiving Day 2014 arrives, agriculture has plenty to be thankful for. Read More
Crop InputsSyngenta Cost-Cutting Program To Affect 1,800 Jobs
November 24, 2014
The company's Accelerating Operational Leverage program will result in job reductions and relocations totaling around 1,800 across the company, the majority of which will occur in 2015. Read More
EquipmentAGCO Announces Operator Of The Year Finalists
November 20, 2014
Four custom applicators have been selected by AGCO Application Equipment as finalists for 2014 Operator of the Year, an honor that recognizes them as being among the top professionals in their industry throughout North America. Read More
MicronutrientsH.J. Baker Expands Tiger-Sul Business
November 20, 2014
H.J. Baker has created and filled two strategic positions in business development and sales within its Crop Performance Division. Read More
soybean field
FertilizerGeneral Mills Honors United Suppliers For Nitrogen Opti…
November 19, 2014
United Suppliers winning proposal detailed SUSTAIN, a consulting network that provides customized products and services for farmers using a needs-based system approach. Read More
EmployeesOhio AgriBusiness Association Awards $25,000 In Scholar…
November 19, 2014
Each year, the Ohio AgriBusiness Association Educational Trust scholarship program awards scholarship dollars to students enrolled in an agriculture-related field attending several state colleges. Read More
ManagementServi-Tech Names New CEO
November 17, 2014
Servi-Tech has named Greg Ruehle its new president and CEO. Read More
CropLife 100Pinnacle Ag Acquires Colorado Aerial Application Outlet
November 17, 2014
Ft. Lupton, CO-based Reck Aviation — a full-service chemical application company providing aerial crop applications of fertilizers and crop protection products — will operate as part of Pinnacle's AgOne Application Services brand. Read More
Eric SfiligojMcDonald’s Message: Biotech Crops Scarier Than Cancer
November 17, 2014
Despite their potential health benefits, one of the world’s largest potato users will pass on a new biotech offering. Read More
MicronutrientsWinField Releases 2014 NutriSolutions Results
November 14, 2014
A number of significant regional and national crop deficiency trends emerged from the 2014 WinField NutriSolutions tissue sampling program. Read More
FertilizerH.J. Baker Opens Chinese Production Lines
November 14, 2014
The occasion was the official launch of the Tiger-Sul sulphur Bentonite production line of two much anticipated fertilizer products in China, T90CR sulphur fertilizer and TZinc micronutrient enhanced sulphur fertilizer. Read More
ManagementOhio Certified Crop Adviser Program Accepting Nominatio…
November 14, 2014
The award recognizes an individual who delivers exceptional customer service for farmer clients in nutrient management, soil and water management, integrated pest management and crop production in Ohio. Read More
HerbicidesSyngenta Announces Acuron Trial Plot Results
November 14, 2014
Acuron was tested at 167 trial locations across 35 states. Trials included 95 Syngenta locations, 54 university locations and 18 distributor locations. Read More
Crop InputsVerdesian Expands Sales Force
November 13, 2014
The new sales representatives will work with growers, retail partners and distributors to oversee technical training and product education. Read More
EquipmentAGCO Raises $100K For Wounded Warrior Project
November 13, 2014
AGCO Corp. partnered with local AGCO dealers across the U.S. and Canada to raise nearly $100,000 in support of wounded service veterans. Read More
HerbicidesDow AgroSciences Announces Launch Of Enlist Duo Herbici…
November 12, 2014
It will be launched in conjunction with a stewarded introduction of Enlist corn, and seed production of Enlist soybeans in 2015. Read More