What does soil application entail?

Soil application refers to the process of applying a pesticide directly to the surface of the soil rather than to the vegetation or plants. This method is often utilized when targeting pests residing in the soil or those that might come into contact with the soil-dwelling pesticide. By applying the pesticide to the soil, it has a chance to penetrate into the root zone where many pests, like certain soil-borne insects or diseases, are located. This technique can be effective for controlling pests that might feed on plant roots or that are present in the soil environment.

In contrast, the other options involve different methods of pesticide application that do not fit the definition of soil application. Applying pesticides directly to plant leaves focuses on protecting or treating the visible above-ground portions of the plants, whereas using an irrigation system implies a method of pesticide distribution that depends on water movement rather than direct soil contact. Creating a pesticide barrier with soil suggests a physical barrier rather than an application method that targets pests in the soil itself. Thus, the correct choice highlights the specific method of soil application effectively.