Corn & Soybean Stories

Understanding Metabolic Weed Resistance

When a weed scientist says a novel weed resistance issue is not well understood, it’s a little concerning.

Most farmers understand the need to apply multiple herbicide groups and rotate them to reduce the number of herbicide-resistant weeds going to seed. This practice reduces target-site weed resistance when a weed alters its genetic code so the chemical no longer fits the protein it was designed to attack.

However, some weeds are evolving to deploy suites of enzymes that work together to metabolize (detoxify) a chemical before it can kill a weed—known as non-target or metabolic resistance...

How the Right Adjuvant Can Optimize Weed Control

Selecting the right adjuvants can make or break the effectiveness of the corn and soybean herbicides in your weed control program.

Choosing the right product begins with reading the herbicide labels. “Every grower or their agronomist or ag retailer recommending products should review each herbicide’s label as a starting point,” says Joe Ikley, North Dakota State University (NDSU) Extension weed specialist. Labels contain specific recommendations such as types and amounts of spray adjuvants, environmental and water quality influences, and mixing procedures.

Ikley says the next step is to...

Sprayer Ownership vs. Custom Application

Deciding between investing in your own self-propelled sprayer or relying on a custom applicator requires evaluating multiple factors beyond how many acres you farm.

First and foremost, you need to explore spraying timeliness and labor considerations before any price shopping begins. Also, factor in which tasks the machine will perform beyond weed control, such as in-season fertility, insect control, multiple fungicide sprays and maybe even cover crop application. Do your business and team have the chemical knowledge, buying savvy, risk aversion, mechanical prowess and proper pesticide/equipment storage facility? And what about considering custom application for neighbors to reduce your costs or sharing ownership with another farmer?

Corn Belt Weather Outlook for Spring Planting

The good news for western Corn Belt farmers is that climate models are not in unison predicting hot and dry weather in 2023 like last year. Instead, current precipitation patterns should trend more normally across the Midwest while helping reduce some western drought areas.

“This year is shaping up to be more of what I would call a normal summer,” says DTN meteorologist John Baranick. “It doesn’t mean everyone gets normal precipitation and temperatures, but we will see plenty of large complexes of thunderstorms moving across the Corn Belt.”

2022 Drought Offers Valuable Lessons

A dry late summer into fall of 2022 had many Midwest corn growers concerned about the drought. More than half of the farmers surveyed in August by Pioneer said they were dealing with moderate to severe drought stress.

“Last summer, coming out of a second consecutive year of La Niña, a predicted drought was already in place across much of the nation’s midsection, especially west of the Mississippi River,” says Brad Rippey, USDA Meteorologist. “I credit the National Weather Service forecasters for nailing the long-range forecast last summer—where the eastern Corn Belt fared reasonably well, and the Northern and High Plains had a tough year with drought and heat combining to really take a toll on crops.”

Five Yield Contest Winners Provide Tips to Yield Like a Champion

Watching the numbers on your yield monitor can cause your emotions to go up and down, depending on what you see displayed on the screen. Regardless of the numbers, you may already be thinking ahead to 2023 and how to take yields to the next level.

National and state yield contest winners may be able to help. And if you think high-yield contests serve no purpose other than bolstering egos, think again. Contest winners say competition pushes them to try new and innovative technologies and agronom

How Herbicide Carryover Can Affect Cover Crops

Proven benefits of cover crops in a corn/soybean rotation have farmers re-evaluating their weed management programs.

One critical risk to evaluate is residual herbicide use and potential carryover given the timing of cover crop seeding. “One of our take-home messages for farmers is to base herbicide selection on weed control first, then adjust cover crop management accordingly,” says Alyssa Essman, Ohio State University weed science research associate.

Corn Height Impacts Post Herbicide Options

Optimal postemergence weed control in corn requires timely application. But if treatment is delayed due to weather, put on your scouting shoes. Corn sensitivity to herbicides generally increases as the plant gets taller, especially if herbicides enter the whorl. Knowing the crop's growth stage will help determine which herbicides to use – and avoid – to prevent crop injury and potential yield loss.

“Check each herbicide label to determine if there are application restrictions by the corn growth stage. If applying a tank-mix,...

Herbicide Layers Reduce Tough Weeds in Corn

A planter tune-up to improve consistent corn emergence is important, but a weed management strategy that properly layers the best available herbicides can put more bushels in the bin this fall.

Uncertain supply chain issues and higher input prices are the biggest challenges to achieving cost-effective weed control in 2022, says Bryan Young, Purdue University weed scientist. “Along with short supply and higher costs of glyphosate and glufosinate, we also hear issues with atrazine supply. As a result, growers may need to change their weed control plan by using premixes that contain atrazine and finding more economical glyphosate options due to a three- or four-fold price hike.”

Grow Cover Crops in Corn Without Yield Loss

Cover crops are well known to provide benefits to the soybean crop like reducing nutrient losses and erosion, suppressing weeds and sometimes suppressing diseases. However, many farmers balk at using cover crops ahead of corn due to a perceived risk of potential yield loss.

Developing management practices that lead to a corn yield increase with cover crops drives Scott Nelson’s research with the Iowa Soybean Association (ISA) Research Center for Farming Innovation. “The reason we believe there is potential for corn to yield more following cover crops relates to soil water...

Cover Crops in Corn – a Good Match?

Cover crop use continues to increase as farmers learn and fine-tune how it fits in a corn and soybean rotation. The annual national cover crop survey among farmers in August 2020 showed small yield increases following cover crops in corn, soybeans and wheat.

Overall, farmers cite that cover crops will deliver healthier soils, lower herbicide and fertilizer costs, reduce erosion and improve weed control, among other benefits.

“I was pleasantly surprised to see 50% of these farmers [in the survey] plant some of their cover crops before harvest,” says Dean Baas, Michigan State University Extension educator in Sustainable Agriculture. “This is a good indicator that farmers seek ways to get cover crops established earlier than postharvest to improve cover crop benefits.”

Rethink Weed Control in Continuous Corn

Continuous cornfields may need extra weed control help in 2022 if glyphosate or glufosinate are the routine postemergence weed control tools, especially in no-till corn. Due to supply chain issues, these two herbicides might be in short supply and may carry a higher price tag.

“Fortunately, there are many good broadleaf herbicides for corn, plus some of our worst herbicide-resistant weeds don’t manifest themselves all that much in corn,” says Bill Johnson, weed scientist with Purdue University. “It also may be a good year to add tillage or cover crops to the mix to reduce reliance on herbicide tools.”

Don’t Skip Residual Weed Control in Corn

Many growers know a total-post weed control program is too big a gamble in any year. But with potential shortages of some postemergence products likely in 2022, this is not the year to risk forgoing residual herbicides.

“We understand that growers sometimes have time-management factors that make total-post an attractive decision to consider. But it’s an even bigger gamble with a limited supply of glyphosate or glufosinate,” says Sarah Lancaster, Kansas State University Extension weed science specialist. “We’re hearing predicted supply issues from retailers who don’t know how available these and other products might be, along with not knowing the price point.”

Volunteer Corn Creates Control Challenges

Extensive corn lodging caused by high winds and thunderstorms leave behind a weed problem that may take some growers by surprise--volunteer corn. Ignoring this weed is costly, particularly when soybeans are planted. Volunteer corn is very competitive, stealing moisture, fertility, sunlight and yield from both soybeans and corn. Even worse, volunteer corn left in the field past silking can encourage western corn rootworm and gray leaf spot disease to invade a subsequent corn crop.

Research by South Dakota State University, the University of Minnesota and the University of Nebraska-Lincoln (UNL) show volunteer corn ranging from 800 to 13,000 plants per acre can steal up to 54% soybean yield and 13% corn yield. Clumps of volunteer corn from dropped ears are more competitive. UNL research found 3,500 corn clumps per acre reduced soybean yields by 40%, while the same population of single plants cut yields by 10%.

Anhydrous Ammonia Application Safety Tips

The physical properties of anhydrous ammonia (NH3) make it one of the most potentially dangerous materials to handle on the farm. Exposure to this colorless, high-pressure liquid, which converts to a liquid gas can cause serious injuries. For example, anhydrous can freeze and/or burn skin, lead to blindness if it gets in the eyes and even cause death when inhaled.

“I can’t overemphasize the importance of safety with anhydrous,” says Ryan Bergman, Technical Project Specialist in Agricultural and Biosystems Engineering at Iowa State University. “It’s critical to always keep tabs on wind direction and stay up wind whenever possible when hooking up, filling tanks, and applying the product, along with keeping a respirator handy at all times.”

Herbicide Resistance Problems Persist

Herbicide resistance has been a part of the weed control landscape for decades now. When it comes to the question of whether this resistance is reversible, unfortunately the answer is no. It's a worst-case scenario: Herbicide-resistant weed species will maintain their genetic superiority over those chemistries as long as their offspring continue to add weed seeds to the soil. Stopping the use of those herbicides won’t reverse those genetics.

“That herbicide-resistance trait will be passed along to the weed’s offspring whether the herbicide is applied or not,” says Pat Tranel, associate head in the Department of Crop Sciences at the University of Illinois. “There’s no negative effect on the trait in the plant. That’s why herbicide resistance increases. There’s an advantage for that resistant gene when the herbicide is used and no disadvantage to the weed when the herbicide isn’t used.”
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