All civilizations have had symbols to represent home, land, earth, or soil, since the beginning of written records. It should be no surprise that we still assign symbols to represent our states, such as an official soil. The Mayan earth symbol (article's thumbnail image) displays a top line that represents time, the circles are the phases of the earth's moon, and the squiggly line is the earth's creative life energy. A small collection of earth symbols is shown in the right sidebar. The circular symbols may represent the earth as the round planet that we know it to be, or the circle of life (birth; life; death).The ones with crosses, or Xs, may represent the four seasons, the four winds, or directional compass points. The V-shapes may represent something different in each culture, but a few are mother, female, and creation. 
Over the last few decades, "soil" has been added to the ever-increasing list of state symbols along with the state flag, motto, song, flower, bird, etc. Initially, I thought this was such a waste of our legislator's time, effort, and taxpayer's money for such a trivial matter. With a quick Internet search, I found I was not the only one who thought so. In some states the topic has been hotly debated, or quietly accepted in others; therefore, some may not know a thing about their state's symbolic soil name.
My mind continued to focus on the official soil concept for days after learning of it. It seemed that every other thing I encountered referred to soil as very important, much more than just a state icon! Scientific research has discovered that certain bacteria in the soil can relieve depression.  That would explain why so many people enjoy gardening and develop a special bond with the land. It makes us feel good! It is not just dirt beneath our feet; it is our land, our home soil! It is what our forefathers yearned for, where our hearts lie, where our children play and grow, the source of feuds, why songs are written, and where our ancestors are buried. For those of us who find ourselves transplanted in other states, and especially other countries, the mention of homeland evokes deep emotion and longing for native soil.
I was anxious to see how my present state of Virginia could possibly decide on one soil to represent the entire state, since the terrain is vastly different from sandy ocean beaches to the rocky forest soils of the Appalachian Mountains. As it turns out, rich minerals from forest soils are carried across the state via rivers that eventually flow into the delta region of the oldest tilled farmland in America, Jamestown. Native Americans from the Pamunkey tribe (like Chief Powhatan and his daughter Pocahontas) helped keep the settlers alive by showing them how, and what, to plant in the rich delta dirt.
Pamunkey is the name of Virginia's official soil! What a beautiful way to capture the essence and the history of the state while honoring both the native inhabitants and its first successful English settlement.  I was deeply touched and very proud to be a resident of the state! I now believe an official soil should have been the very first symbol adopted by each state!
Are you wondering what your state's official soil is, too? Here is a chart of the official soil name for each state. Although all the states have a representative soil, only twenty have been made official by legislation, as noted by the adoption date.   What little information I could find on Canada's official soils is included in the chart as well, but I found that the designated soil names were sometimes different after they were proclaimed. 
For additional information about the official soils of your state, or just the dirt:
 Avia Venefica. Whats-Your-Sign.Com. Earth Symbols and Meanings.