Abstract:

Soil microorganisms are the main body for N transformation. Soil organic matter and rhizodeposits are driven forces for microbial N transformation. The objective of this review was to address the effect of fertilizer input or organic matter amendments on nitrogen transformation aroused by soil microorganism. We found that fertilizer input or organic matter amendments had an effect on soil N transformation through indirect affecting photosynthates translocation and mineralization of labile organic matter, or directly providing solute for microorganism. As a result, fertilizer input and organic matter amendments impact microbial biomass, community structure, abundances of genes involved in nitrogen transformations or microbial produced enzymes. Crop roots affected microbial number and activity through rhizodeposits or residue return. Microorganisms mineralized soil organic mater or organic inputs according to their needs for C, N or energy. So soil organic mater content significantly affects microbial nitrogen transformation except for organic matter amendments. In conclusion, fertilization had direct/indirect effects on soil microorganism, accordingly had an effect on soil nitrogen forms, and consequently had an effect on crop N uptake.