Reference soil United States of America 13: Chernozem
Chernozems are typically found in the long-grass steppe regions of the world, particularly in Eastern Europe and North America (Canada and the USA).
Characteristics
Soils having a very dark mollic horizon (thick, brownish or blackish surface horizon with a significant accumulation of organic matter and high base saturation) and secondary carbonates within 50 cm of the lower limit of the Ah horizon, but within 200 cm from the soil surface. They have no petrocalcic horizon between 25 and 100 cm from the soil surface, no secondary gypsum and no uncoated sand and silt grains on structural pedfaces
Reference soil US013: Chernozems
PROFILE DESCRIPTION: Bt1: colours also dark greyish brown (10YR 4/2, dry) and dark brown (10YR 3/3, moist) BC: streaks, light brown (2.5Y 6/2, dry) and dark greyish brown (2.5Y 4/2, moist) and 0.5cm wide, occur discontinuous across the horizon C: streaks as in BC horizon