Sentence:  A sequential phosphorus (P) fractionation procedure was used to measure the changes in the labile and stable forms of inorganic and organic P following single broadcast P applications to Canadian <WSD>Chernozemic</WSD> soils under cereal cropping. 
Meaning of the word marked with <WSD> tags:  Of or pertaining to an (order) of (soils) with (chernozemic) characteristics.