Effect of long-term fertilization on phosphorus and zinc fractions in a Mollisol Effect of different fertilizaiton on microbial community in an arable mollisol Characteristics of soil organic carbon and nitrogen distributed in different density fractions of mollisols under long-term continuous cropping and natural restoration A review of researches on evolution of soil organic carbon in mollisols farm-land Effect of conservation tillage on microbial community in Chinese Mollisol Relationship between landscape pattern and soil erosion of an agricultural watershed in the Mollisols region of northeastern China Distribution and enrichment characteristics of organic carbon and total nitrogen in mollisols under long-term fertilization.