Chlortoluron is primarily used as a selective herbicide in agriculture, especially in the control of annual grasses and certain broadleaf weeds. It is commonly applied in cereal crops such as wheat, barley, and rye, where it effectively suppresses weed growth without harming the crop when used at recommended rates. The herbicide works by inhibiting photosynthesis in susceptible plants, leading to their gradual decline and death. It is often used in pre-emergence or early post-emergence treatments, providing residual control over key weed species that compete with crops for nutrients, light, and water. Due to its soil activity and moderate persistence, chlortoluron helps maintain clean fields during critical early growth stages. Its application is particularly valuable in regions with high weed pressure, contributing to improved crop yields and reduced manual or mechanical weeding. However, its use has declined in some areas due to environmental concerns, including groundwater contamination and persistence in soil, leading to regulatory restrictions in certain countries.