Which factor does NOT affect the application efficiency of herbicides?

The application efficiency of herbicides can be influenced by various factors that directly affect how well the herbicide works in real-world conditions. Environmental conditions, such as temperature, humidity, and wind speed, can significantly impact the efficacy of herbicides by affecting their absorption and degradation rates. Operator experience plays a crucial role as well; a knowledgeable operator can determine the appropriate application rates, timing, and techniques, which enhance the overall effectiveness of the herbicide.

The type of herbicide is also a significant factor, as different herbicides have varying modes of action and levels of efficacy against specific target weeds. The chemistry of the herbicide, along with its formulation, can influence how it is absorbed by the plants and how long it remains active in the environment.

Soil fertility, while important for overall plant growth, does not directly influence the application efficiency of herbicides. It pertains more to the growth and health of the plants present and does not affect how well the herbicide is applied or its effectiveness in controlling weeds. Therefore, soil fertility stands out as a factor that does not alter the application efficiency of herbicides.