Chernozem

Chernozem (/ˈtʃɜːrnəzɛm/ CHUR-nə-zem), also called black soil, black earth, dark earth, regur soil or black cotton soil, is a black-colored soil containing a high percentage of humus (4% to 16%) and high percentages of phosphorus and ammonia compounds. Chernozem is very fertile and can produce high agricultural yields with its high moisture-storage capacity. However, prolonged agricultural use of chernozems still require replenishment with fertilizers because they easily can get depleted of nutrients through continuous decrease in humus content. Chernozems are a Reference Soil Group of the World Reference Base for Soil Resources (WRB). Chernozem is commonly found throughout the steppes of Russia and Ukraine, the American and Canadian Great Plains, and the South American Pampas according to most recent studies.