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What happens when chemical controls are removed from row-crop agriculture?


FAYETTEVILLE — Taking pest control chemicals out of agriculture would lead to increased use of valuable natural resources and an attendant rise in greenhouse gases, according to a study born of three years of data collection.
“The consequence of not having access to these pest controls would be that it would take more land, more water, more greenhouse gas emissions and more energy to produce the same amount of crops,” Marty Matlock, professor in the department of biological and agricultural engineering, said in a Food, Farms & Forests podcast. “We’re going to have to make sure we have enough to produce enough with the land we have.”
Matlock is part of a team of Arkansas and Colorado scientists who calculated the impacts of taking chemical pesticides out of agriculture for the nation’s top three commodity crops.
As the global population grows to 10 billion in the coming years, the report showed that chemical pesticides — including insecticides, herbicides and fungicides — will be critical to producing the food and fiber we need with the current available land and resources.
Matlock teaches ecological engineering and conducts research as part of the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture. He previously served as the executive director of the University of Arkansas Resiliency Center and served as a senior advisor to Secretary of Agriculture Tom Vilsack.
He and four colleagues conducted a cradle-to-farm gate life cycle assessment on the nation’s three largest commodity crops — corn, cotton and soybean — which account for about 70 percent of the nation’s agricultural lands spread across the U.S. Midwest. A life cycle assessment considers everything required to produce something and quantifies it per unit of yield.
The life cycle assessment investigated the removal of chemical pesticides in the crops with four primary impact categories: short-term (100-year) climate change, fossil and nuclear energy use, land use measured as land occupation and biodiversity, and water consumption.
The assessment showed the most significant impact of no chemical controls was on soybeans due to insect pressure leading to yield loss. The second and third most significant impacts were weed pressure in soybeans and insect pressure in cotton. Corn had the most loss from a lack of weed and insect control. Adding cover crops to the rotation did not significantly change the four primary impact categories compared to the baseline, indicating that cover crops do not increase these sustainability metrics. However, the researchers did not include expected benefits of cover crops like soil health values as a primary impact category.
Compiling the information needed for the life cycle assessment called for collecting data on six growing seasons at the county level in the nation’s top agricultural producing states for each commodity crop. The scientists simulated fields of operations across 40 archetype production systems for each crop using the Agricultural Policy Extender model, also known as APEX.
Matlock said pesticides are heavily regulated in the United States for user and consumer safety. Still, their study focuses solely on the impacts of removing chemical pesticides from the three commodity crops.

“There is a cost, a risk, associated with the use of pesticides, and there’s a cost, a risk, associated with not using the pesticides,” Matlock said. “What happens when you take them out? What we showed is that it’s really bad. The impacts were increased greenhouse gas emissions, increased water use, increased land use and increased energy use.”
Greg Thoma, director of agricultural modeling and lifecycle assessment at Colorado State University, was the lead author of the life cycle assessment. Co-authors included Kyle Lawrence, a biological engineering research technician at the University of Arkansas; Jacob Hickman, a University of Arkansas engineering graduate research assistant; and Brandon Taylor, a research assistant in the University of Arkansas’s biological and agricultural engineering department.
What prompted the study?
CropLife America, which represents pesticide makers, prompted and provided funding support for the life cycle assessment.
“They have a vested interest in advocating for the use of chemicals. We do not,” Matlock said. “They came to us because we’re independent scientists and wanted to know if we could answer the question: ‘Is it bad to take these things out of these three crops from a sustainability perspective?’
Matlock said talk of removing pesticides from agriculture prompted the study’s question, centered around a conversation of sustainability and regenerative agriculture.
“Those are well-intended concepts, but they’re ill-informed because they don’t understand what happens if you do that,” Matlock said of removing pesticides from agriculture. “It won’t be profitable for farmers. And if it’s not profitable, who’s going to grow? Because the fact is, farming is a business. So that’s why they were interested. And we’re interested because it’s a reasonable scientific question to ask.”
The life cycle assessment conforms to International Standard Organization standards and was peer-reviewed. Matlock noted that the work is being submitted for an additional peer-review process for journal publication.
Looking ahead
Scientists with the Arkansas Agricultural Experiment Station and other land-grant university systems continue researching and helping develop ways to decrease pesticide use by breeding plants for disease resistance and adaptation to climate change. Work is also being done to reduce herbicide drift, develop bioherbicides, and research innovative technologies such as microwaves to inactivate weed seeds.
Experiment stations also conduct studies to develop economic thresholds, maximize yield potential, conserve water and nutrients, improve processing efficiencies and food safety techniques, and upcycle agricultural waste products.