Which classification refers to organic silts and silt clays with low plasticity?

The classification that refers to organic silts and silt clays with low plasticity is indeed OL. The Unified Soil Classification System (USCS) categorizes soils based on their physical properties, including their plasticity and organic content.

OL represents organic silt, which is characterized by the presence of organic matter in sufficient quantities to influence the soil behavior, typically resulting in a lower plasticity index compared to inorganic silts. The designation indicates not only that the soil is silt but also that the organic component contributes to its properties, distinguishing it from other classifications.

In comparison, other classifications such as CL and ML-CL involve clays and silts with different characteristics and plasticity levels, while OH indicates organic clays, which would typically have a higher plasticity associated with their organic content. Hence, OL is the correct identification for organic silts and silt clays that possess low plasticity.