FERTILIZATION AND SOIL MICROBIAL CH

FERTILIZATION AND SOIL MICROBIAL CHARACTERISTICS 807
stable value. Our experimental site has a long cultivation history and the organic C content is in a
relatively stable stage. The soil with the different fertilizing treatments was yielding the same crops
including soybean in a three-year rotation. Although fertilization had resulted in crop yield increase
(Wang et al., 2003), it was not sufficient to trigger a significant change in the soil microbial properties.
However, from a longer time view, how different fertilizing treatments affect soil microbial properties
and how to use soil microbial indicators to assess soil quality change need to be further studied. In
conclusion, 13 years of continuous application of chemical fertilizers did not result in a significant change
in the soil microbial biomass and the functional diversity of the black soil