What property of soil is primarily associated with its ability to stick together?

The primary property of soil that is associated with its ability to stick together is cohesion. Cohesion refers to the intermolecular forces that hold soil particles together, particularly among fine-grained soils like clay. It is a critical factor in determining the stability and strength of soil structures, as it affects the soil's ability to resist deformation. In cohesive soils, the particles adhere to each other, enabling them to form stable aggregates or clumps, which is essential in situations such as slope stability and the construction of earth structures.

Liquid limit refers to the moisture content at which soil transitions from a plastic state to a liquid state, which relates more to soil behavior than its cohesive properties. Shear strength is a broader term that encompasses both cohesion and friction, determining the soil's capability to resist sliding. Compressibility describes how much a soil will change in volume under applied loads, which does not directly relate to its sticking ability. Therefore, cohesion specifically highlights the particles' attractive forces that enable soils to maintain their structure and resist erosion or collapse.