养分投入和作物根系对土壤微生物氮转化的影响

Impact of Fertilization and Crop Roots on Microbial Nitrogen Transformation

土壤氮转化的主体是微生物,土壤有机质与根系分泌物是微生物氮转化的驱动力。综述了养分投入和作物根系通过微生物对土壤氮转化的影响。指出化肥或有机肥的投入,通过改变光合产物向根系的分配和土壤难/易有机质的数量,或直接提供微生物底物方式,改变微生物生物量、群落结构、氮转化功能基因的数量或相关酶的产生,从而影响土壤氮的转化;还指出根系通过根系分泌物或根茬还田影响土壤微生物的数量和活性,土壤有机质含量也显著影响微生物氮转化过程。总之,养分投入通过直接或间接方式影响土壤微生物,进而影响土壤养分的存在状态,最终影响作物对养分的吸收。

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 microorganisms.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 microorganisms.As a result,fertilizer input and organic matter amendments impacted 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 affected 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.