The primary determinant of soil fertility is the presence of essential nutrients, particularly nitrogen, phosphorus, and potassium, as well as organic matter that enhances nutrient retention and biological activity. Soil composition, pH, and microbial activity also play significant roles in determining fertility levels. Fertile soils support healthy plant growth, which is critical for agriculture and supporting ecosystems. Additionally, fertility is influenced by the management practices in place, such as crop rotation, organic amendments, and erosion control. Sustainable practices are vital for maintaining soil fertility to ensure long-term productivity and ecosystem health.