Which of the following soil properties is NOT used to develop a K factor?

The K factor, which is an important component of the Universal Soil Loss Equation (USLE), quantifies soil erodibility based on its susceptibility to erosion by water. To determine the K factor, several soil properties are evaluated, most notably particle size distribution, organic matter content, and soil structure.

Particle size distribution indicates the percentage of sand, silt, and clay within the soil, affecting how easily the soil can be eroded. Organic matter content significantly influences soil aggregation and erosion resistance, as higher organic matter typically enhances soil stability. Soil structure refers to the arrangement of soil particles and the size and shape of the pores between them, which affects water infiltration and the potential for erosion.

Bulk density, while a valuable soil property in various contexts, is not one of the primary factors used in calculating the K factor. Instead, bulk density can provide insights into soil compaction and porosity, which might affect erosion indirectly, but it does not directly contribute to the evaluation of erodibility associated with the K factor. This makes it the correct choice in this context.