This chapter focuses on the concept of “One Health,” a global, collaborative, multidisciplinary effort to attain optimal health for plants, animals, people, and the environment. In this relationship, the fungi benefit from carbon resources provided by the plants, and in most cases, arbuscular mycorrhizal fungi enhance plant health through different mechanisms. The efficiency at which soil minerals are absorbed by plants is critical to human and animal health. Healthy and diverse soil organism populations reduce the impact of plant and soil pathogens that can negatively affect the growth of forage and grains needed to feed humans and animals. Healthy soil contains an optimal balance of macro- and micronutrients to support the health of plants, animals, and humans. Exposure to pesticides generally reduces the number of neutral or beneficial organisms and facilitates the overgrowth of pathogenic organisms in soil, whereas the addition of biochar can increase the soil's microbial diversity and plant health.