What formula is used to calculate the moisture content of soil?

The formula used to calculate the moisture content of soil defines moisture content as the ratio of the mass of water present in the soil to the mass of the solids present in the soil after they have been dried in an oven.

The correct formula states that moisture content is expressed as the mass of moisture divided by the mass of oven-dry soil, multiplied by 100 to convert it to a percentage. This method is reliable and widely accepted in geotechnical engineering as it allows for an accurate representation of how much water is present in the soil relative to the solid particles alone, excluding any influence from the weight of the moisture-soaked soil.

This distinction is critical because moisture influences soil behavior, such as compaction and shear strength, and using the mass of oven-dry soil ensures that the water content is assessed in terms of the solid framework upon which it operates.

The other options presented do not accurately reflect this standard calculation. For instance, using the mass of wet soil instead of oven-dry soil would lead to inflated moisture content values, as it includes the weight of the water in the wet soil already. Thus, option B captures the essential aspect of measuring moisture content in soil appropriately.