What contributes significantly to soil's nutrient content?

Organic matter plays a crucial role in enhancing soil's nutrient content because it comprises decomposed plant and animal material that enriches the soil with essential nutrients such as nitrogen, phosphorus, and sulfur. These nutrients become available for uptake by plants, making organic matter a key component of soil fertility. Additionally, organic matter improves the soil's structure, water retention, and microbial activity, which are all vital for a healthy ecosystem.

While sand particles provide aeration and drainage, they lack the nutrient-holding capacity that organic matter provides. Clay minerals are important for nutrient and water retention due to their high surface area, but they require organic matter to be most effective in nutrient availability. Soil water is necessary for transporting nutrients to plant roots but does not contribute to the nutrient content itself. Thus, while each of the other options has its importance, organic matter stands out as the primary contributor to soil nutrient content.