Soil ______________ is the proportion of sand, silt, and clay particles in the soil.

Texture is the correct term used to describe the proportion of sand, silt, and clay particles in the soil. Soil texture influences many important characteristics, including water retention, aeration, drainage, and nutrient availability. The specific blend of different particle sizes determines how well the soil can support plant growth and affects various physical properties of the soil.

Fertility refers to the soil's ability to provide essential nutrients to plants, while composition encompasses the various components that make up the soil, including mineral content and organic matter. Moisture pertains to the water content within the soil but does not address the specific ratios of sand, silt, and clay. Thus, while all the terms relate to soil, it is texture that specifically defines the proportions of the different particle sizes.