The official state soil of Alaska is Tanana, named after the Tanana river (the name Tanana is derived from the Athabaskan word for "mountain river"). Tanana soil is found in the Fairbanks area and extensively thoughout the lowland areas of interior Alaska. Tanana soils are important to agriculture in Alaska. They support a native plant community of aspen, paper birch, white spruce, and black spruce. When cleared and cultivated, tanana soils are used for hay and pasture, small grains, and vegetables.

Alaska has 318 different soil types and approximately 15 million acres of soil that is suitable for farming. Because of nearly constant sunlight on summer days, some crops can grow to enormous size. Examples include a world record 19 pound carrot, a 76 pound rutabaga, and a 106 pound cabbage!

Source:

A Look at Alaska Agriculture (PDF): Alaska Farm Bureau
Tanana - Alaska State Soil (PDF): USDA

Links:

Geological Symbols - 50 States List