Pedologist Interview Question:

Tell us what different particles does dirt contain?
How much of each particle are in 1/2 a cup of dirt?

Submitted by: Muhammad

Soil particles are defined as less than 2 millimeters in diameter. Particles larger than that are called gravel or rocks.
Soil particles come in three sizes:

☛ Sands are the largest, and are coarse and gritty. They allow water and air to move into and through the soil because there are large pores (holes) between them.
☛ Silts are the middle-sized soil particles, and are smooth. They feel much like flour or baby powder. They hold water that plants can use.
☛ Clays are the smallest soil particles, and are fine and sticky. They hold a lot of water, but do not give as much to the plants as silts. They also hold nutrients. They help hold soil together in clods which scientists call aggregates. Clays can be molded and shaped, much like modelling clay or Play-Dough.
☛ An ideal soil would have equal amounts of sand, silt, and clay particles. But most soils are not ideal. Some are mostly sand, others are mostly clay or silt, depending on where they are found. The about equal mixtures of soil particles are called loams.
Submitted by: Muhammad