Effect of Land Use and Fertilization on Soil Microbial Abundance and Diversity in the Black Soil Region in Northeast China

The diversity and abundance of soil microorganisms are affected by land use and fertilizer application, and these microbial community attributes can provide an insight into soil health. Two methods, microbial plate culture and PCR-DGGE, were employed to study the dynamic changes of the microbial communities in a typical black soil in a long-term land use and fertilization field experiment in Northeast China. Three land use ecosystems were studied, grass land ecosystem (GE), bare land ecosystem (BE), and crop land ecosystem (CE). Fertilization treatments were applied only in cropped land ecosystem and consisted of no fertilizer (CK), chemical fertilizer (NP), and chemical fertilizer combined with manure (NPM). The results indicated that human activities in CE have altered both the diversity and abundance of soil microorganisms. Fertilizer increased the diversity and abundance of the microbial community indicating enhanced soil fertility. Fertilizer together with composted manure enhanced both abundance and diversity of the microbial community compared to synthetic fertilizers alone. The diversity of the microbial community was highest in GE, followed by CE, and was lowest in BE.