Which of the following is NOT a method for herbicide application?

Soil layering is not recognized as a method for herbicide application. In herbicide application, techniques are typically designed to ensure that the herbicide comes into direct contact with the targeted plants, thereby maximizing its efficacy against weeds or unwanted vegetation.

Surface spraying involves applying a liquid herbicide onto the foliage of plants, which is a common and effective method for controlling weed growth. Injection refers to delivering the herbicide directly into the plant's vascular system, often used for specific types of trees or deep-rooted plants. Granular spreading involves distributing solid-form herbicides over the soil surface, utilizing the soil moisture to dissolve and activate the herbicide, which then targets weeds.

Soil layering, on the other hand, is not a recognized practice for applying herbicides and is more associated with soil management techniques rather than direct herbicide application. This distinction is crucial for understanding proper herbicide application methods and their effectiveness in weed control.