In terms of agricultural practices, pesticides are primarily used for what purpose?

Pesticides are primarily used for controlling pests, which includes insects, weeds, fungi, and other organisms that can harm crops. The main goal of using pesticides is to protect agricultural productivity and the health of plants by minimizing damage caused by these harmful organisms. By effectively controlling pest populations, farmers can reduce the competition for resources that crops need to thrive.

While some of the other options relate to agricultural practices, they do not accurately describe the primary function of pesticides. Fertilizing soil is achieved through the use of fertilizers that provide essential nutrients to plants, not pesticides. Improving water quality typically involves practices aimed at reducing runoff and contaminants rather than the application of pesticides. Enhancing crop yield can be a beneficial outcome of using pesticides, as controlling pests allows plants to grow more robustly; however, it is not the direct purpose of pesticides themselves. Therefore, controlling pests is the fundamental reason for their use in agriculture.