Agricultural pesticides are used as a form of protection for crops and to maintain optimal levels of production; they prevent pests and weeds from ruining the harvest. Just like medicine, we spray those pesticides in specific quantities at specific times.
It is composed of chemical substances. As global warming intensifies, researchers aim to investigate the impact of weather conditions on herbicides. Indeed, many previous studies have shown that herbicides applied to the same soil become less effective.
A research group from the University of Illinois decided to investigate the types of herbicides applied to weeds after they have grown, solving a puzzle for scientists. They discovered that the effectiveness of herbicides against weeds is similar to that of soil-applied herbicides. They published their study in the journal "Weed Science" on November 24, 2024.
The researchers gathered data on herbicides from 16 weed science programs from a 30-year database, conducted a thorough analysis, and determined the extent to which weather influences the effectiveness of herbicides applied after growth or emergence. This means they used large datasets over an extensive time period and analyzed them thoroughly, which distinguishes this study from others.
Researchers have observed that changes in weather conditions, whether in air temperature or rainfall rates, resulting from climate change, may reduce the effectiveness of herbicides applied after weed growth, affecting three main crops: beans, corn, and soybeans. This means that the impacts of climate change have extended to agricultural production, which in turn affects global food security.
Researchers found that if the weather is warm before applying the pesticide, it provides an ideal opportunity for weed growth, leading to a larger number of weeds that the pesticides cannot control. During the warm period following application, the metabolic processes of the plants intensify, thereby diminishing the effectiveness of the pesticides. In the case of cold temperatures, the metabolic process slows down, which weakens the movement of the pesticide within the plant, making it less effective.
Researchers also found that rainfall patterns, whether dry or rainy conditions, affect the effectiveness of herbicides. For example, if drought conditions occur about 10 days before applying the herbicide, a waxy layer forms on the surfaces of the weed leaves, making it difficult for the herbicide to penetrate the plant. However, if humid conditions spread 10 days after applying the pesticide, it means that the humidity washes away the pesticides applied to the weedsleaves. In any case, the effectiveness of the pesticide decreases.
The authors of the study believe that the challenges associated with climate change significantly impact the agricultural sector, which means that farmers need to adopt measures that are more adaptable to the new conditions, especially regarding pesticides.
