What is the primary component of soil?

The primary component of soil is a combination of mineral and organic matter. Soil consists of various components, and mineral matter, which includes particles derived from the weathering of rocks, forms a significant part of soil structure. This mineral fraction typically constitutes about 45% of the soil volume.

In addition to mineral matter, organic matter, which comes from the decomposition of plants and animals, is crucial for soil health. It contributes to nutrient availability, soil structure, and moisture retention, playing an essential role in supporting plant life. The synergy between mineral and organic components allows for a well-balanced ecosystem within the soil.

While the other options may represent components or types of soil, they do not encompass the entirety of what constitutes soil. Sand and gravel refer specifically to certain particle sizes, while organic compost is a form of organic matter but not the primary component of soil as a whole. Clay and silt also pertain to specific soil textures but do not represent the broader classification that includes minerals and organic matter. Thus, the most comprehensive and correct answer is that the primary component of soil is indeed the combination of mineral and organic matter.