Specialist: Residual Herbicides No Match For Wet Soil

Soil-applied herbicides can knock out a grower’s toughest weeds but the chemical products are no match against soggy fields, says Bill Johnson, Purdue University Extension weed specialist.

A wet early spring has made it difficult for crop producers to apply soil-applied, or residual, herbicides to their fields ahead of planting. Producers should not push the envelope on herbicide treatments while fields are holding too much water, Johnson says.

“If it’s dry enough to plant, it’s dry enough to spray,” Johnson says. “We don’t plant our crops when soil conditions are such that we’re dropping the seed into mud, so we don’t want to apply our herbicides onto muddy ground, either.

“We run into challenges when we apply to fields that are too wet. One, we’re going to leave ruts in the field. Two, all herbicides are labeled such that they cannot be applied to standing water anyway. If we want to get the most out of our soil-applied herbicides, we need to put them on in conditions similar to those in which we would plant the crops.”

As their name suggests, soil-applied herbicides are sprayed on the soil before, during or just after crops are planted. While too much water nullifies their effectiveness, most residual herbicides need some soil moisture in order to work properly.

The herbicides are activated by moisture within the soil and are then absorbed by weed seedlings. Weed growth stops or is stunted, leading to plant death shortly after it emerges.

“A residual herbicide will have activity in the soil anywhere from about one to six weeks after application, depending on the product that you use,” Johnson says. “So what you essentially get, then, is herbicide activity that you don’t really see, because you have fewer weeds coming up. The weeds that do emerge from that residual system are going to be a little bit easier to control with your post-emerge herbicides.”

Excessive wetness isn’t the only challenge to using soil-applied herbicides. Johnson say growers should be careful to:

  • Choose the right residual product. “You have to know which weeds you’re going after,” Johnson says. “The most effective residual herbicides are going to be matched to the weed species that are in that field. For instance, if you have a giant foxtail weed problem, using a broadleaf herbicide is not going to be of much value in that field. You want to use a herbicide that’s active against grass weeds.”
  • Apply at the proper carrier volume. Johnson says glyphosate is one of the few foliar herbicides that works well at carrier volumes of 15 gallons per acre or less, which is why it is often tank mixed with residual herbicides. Contact herbicides, such as paraquat or Gramoxone, require 15-20 gallons per acre, he said.
  • Avoid applying in windy conditions, to prevent spray drift.
  • Rotate between products and weed control practices, to minimize the development of herbicide resistance.

“More than 90 percent of our soybeans and 70 percent of our corn are glyphosate- or Roundup-tolerant crops, so it’s going to be important for us to treat that technology as an investment,” Johnson said. “We want to keep that technology around for as long as possible, and the way we do that is to minimize selection pressure for glyphosate-resistant weeds.

“Using the appropriate residual herbicide on your worst weed problems and then saving glyphosate for the post-emerge cleanup treatment, is going to be the best way to protect crop yields and slow the development of glyphosate-resistant weeds.”

For more information on weed control in agricultural crops, visit the Purdue Weed Science Web page.

(Source: Purdue University)

Leave a Reply

Herbicides Stories

Crop InputsEU Glyphosate Controversy Heating Up Yet Again
August 17, 2016
The battle over glyphosate rages on in Europe, creating a lot of question marks over whether the herbicide will continue Read More
Winter Wheat
HerbicidesNew Wheat Herbicide Helps Growers Manage Resistant Weeds
August 2, 2016
Quelex herbicide from Dow AgroSciences is now registered by the U.S. EPA, providing wheat growers a new solution for advanced Read More
Palmer pigweed seedhead in cotton
HerbicidesStudy: Fall Weed Controls Can Make Significant Impact On Glyphosate-Resistant Palmer Amaranth
July 28, 2016
An article published in the latest issue of the journal Weed Science shows that adopting harvest-time and post-harvest weed controls Read More
Palmer pigweed in soybean stubble
HerbicidesSpecial Issue Of Weed Science Explores Human Aspects Of Herbicide Resistance
July 27, 2016
Weeds that evolve resistance to herbicides are a serious threat to global agricultural production. In this Special Issue of Weed Science, Read More
Trending Articles
Key Cooperative Marcus Construction Steel Building
Retail FacilitiesMarcus Construction Builds High-Speed Agronomy Center For Key Cooperative
July 7, 2016
Key Cooperative in Grinnell, IA, wanted a state-of-the-art Agronomy Center to better serve its customers. Marcus Construction delivered exactly that. Read More
Heritage Cooperative
Retail FacilitiesKahler Automation Designs State-Of-The-Art Facility For Heritage Cooperative
July 4, 2016
Heritage Cooperative in Marysville, OH, needed an efficient liquid, dry and grain facility to serve the many needs of their Read More
The Andersons Waterloo
ManagementFirst Indiana Facility Certified Under 4R Nutrient Stewardship Certification Program
June 27, 2016
The 4R Nutrient Stewardship Certification Program has announced that The Andersons, Inc.’s Waterloo, IN, facility has been added to its Read More
Food IT
Industry NewsCalifornia Event Will Mix Ag And Tech Professionals To Explore IT Solutions
June 20, 2016
Silicon Valley is hot on agriculture, and an upcoming event in California will bring together the food and tech industries Read More
Monsanto Luling Plant
Eric SfiligojWhat’s Next For Monsanto?
May 31, 2016
For the folks at Monsanto’s headquarters in St. Louis, MO, it has been an eventful few weeks. Back on May Read More
Soybean Plant closeup
Industry NewsMonsanto Rejects Bayer Bid; Open To More Talks
May 25, 2016
Monsanto Co, the world’s largest seed company, turned down Bayer AG’s $62 billion acquisition bid as “incomplete and financially inadequate” Read More
Latest News
Crop InputsDuPont Pioneer: Corn Belt P and K Levels Lagging
August 24, 2016
A new DuPont Pioneer study conducted across 12 Corn Belt states demonstrates that growers may be leaving profit potential in Read More
Monsanto sign
Crop InputsCould a Monsanto-Bayer Union Be 2 Weeks from Fruition?
August 24, 2016
Via STLToday.com (The St. Louis Post-Dispatch): Merger talks between Monsanto Co. and Bayer AG are advancing after a series of Read More
EquipmentCase IH Debuts Nutri-Tiller 955 Strip-Till Applicator
August 24, 2016
With strip-till continuing to expand across new acres, Case IH designed the new Nutri-Tiller 955 strip-till applicator to help producers Read More
EquipmentCase Launches Aim Command FLEX, 25th Anniversary Patrio…
August 24, 2016
Case IH announces new AIM Command FLEX advanced spray technology for greater application accuracy, as well as special 25th Anniversary Read More
ASMARK 2016 Retailers Live! Tour - CPS
CropLife 100CPS Acquires Texas Retail Operation
August 23, 2016
Crop Production Services (CPS) has acquired the assets of Larry’s Chemical and Spray, Inc., for an undisclosed amount in an Read More
PrecisionAg Video Conference
Precision AgVideo: PrecisionAg Vision Conference
August 22, 2016
A Strategic Conference Focused on the Future of Farm Digitization and Precision Agriculture Visit precisionagvision.com and register today! Read More
Young Corn Plants
Industry NewsOABA Welcomes Nicole Wallace As Communication & Adm…
August 22, 2016
The Ohio AgriBusiness Association has hired Nicole Wallace as its communication and administrative coordinator. Wallace will help provide comprehensive communication Read More
Syngenta Sign
Crop InputsChemChina, Syngenta Receive Clearance From CFIUS
August 22, 2016
China National Chemical Corp. (ChemChina) and Syngenta have announced that the companies have received clearance on their proposed transaction from the Read More
ManagementAg Industry Shows and Rumors
August 18, 2016
Editors Paul Schrimpf and Eric Sfiligoj talk about the upcoming trade show schedule, crop protection merger updates, and content for Read More
MAGIE 2015
EquipmentMAGIE Takes The Pulse Of The Ag Retail Industry
August 18, 2016
Every year, one of the major highlights of my career as an ag journalist is attending the Midwest AG Industries Read More
MAGIE 2015 Overview
EquipmentPride In Professionalism On Display At MAGIE
August 18, 2016
The Illinois Fertilizer & Chemical Association (IFCA) is proud to partner with CropLife IRON and continue the tradition of bringing Read More
SprayersJenner Ag To Debut 25th Anniversary Edition Case IH Pat…
August 18, 2016
Visitors at the 2016 Midwest Ag Industries Exhibition (MAGIE) in Bloomington, IL, will have a unique photo opportunity, as Jenner Read More
Crop InputsEU Glyphosate Controversy Heating Up Yet Again
August 17, 2016
The battle over glyphosate rages on in Europe, creating a lot of question marks over whether the herbicide will continue Read More
Industry NewsNew Partnership Provides Improved Representation At Ohi…
August 16, 2016
The Ohio AgriBusiness Association (OABA) has retained Belinda Jones of Capitol Consulting Group, Inc. (CCG) for government relations work in Read More
Tissue testing
FertilizerMosaic: 6 Tips For Better Crop Nutrition In Corn
August 16, 2016
Late in the crop season is a good time to assess visual nutrient deficiencies and ensure early- and mid-season deficiencies Read More
WebinarsWebinar Schedule
August 14, 2016
Register for one of our upcoming Webinars or access our archive of past Webinars to view recordings of presentations that may be of interest to you. Read More
Dow DuPont
Crop InputsDowDuPont Update: EU Takes Closer Look at Merger
August 12, 2016
Dow Chemical Co. and DuPont Co. face months of haggling with European Union antitrust regulators who opened an in-depth probe Read More
ManagementNews from InfoAg 2016 and Weed Wands
August 11, 2016
Editors Paul Schrimpf and Eric Sfiligoj review what happened at last week’s big Precision Ag event and a possible solution Read More