A research team led by Prof. WU Zhengyan at Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science of the Chinese Academy of Sciences, managed to develop a near-infrared light-responsively controlled-release herbicide to reduce pesticide loss and then to increase the utilization efficiency.

Pesticides contribute greatly to agriculture as they can effectively control diseases, pests and weeds in farmland. However, traditional pesticides can be easily lost into soil through leaching, causing serious pollution and low utilization efficiency (UE). Therefore, the development of new pesticide formulations to reduce pesticide loss, increase UE, and decrease usage, has become a focus of agricultural and environmental research.

In this study, the researchers fabricated near-infrared light (NIRL) responsively controlled-release herbicide particles (NCHPs) using biochar, attapulgite (ATP), NH₄HCO₃, ethylcellulose (EC), silicon oil (SO), and glyphosate (Gly). The resulting complex was granulated and coated by EC and SO to form NCHPs.

They found that biochar acted as a photothermal agent with a photothermal conversion efficiency of 38%, to convert light energy into thermal energy, thus triggering NH₄HCO₃ decomposition into CO₂ and NH₃ that broke through the coating and facilitated Gly release. Besides, they revealed that NCHP showed a higher control efficacy on weeds than Gly alone.

This study may provide a promising method to control the release of Gly, increase utilization efficiency, and decrease environmental contamination.

The study was supported by the Science and Technology Service Programs of the Chinese Academy of Sciences, the National Key R&D Program of China, the Key R&D Program of Ningxia Province, the Science and Technology Major Project of Anhui Province, and the Environmental Protection Project of Anhui Province.

Schematic illustration of mechanism. (Image by LIU Bin)