Relationships of microbial biomass carbon and nitrogen with particle composition and nitrogen mineralization potential in calcareous soil
石灰性土壤微生物量碳、氮与土壤颗粒组成和氮矿化势的关系

Taking 25 surface soil samples of calcareous soil with greater difference in fertility on Loess Plateau as test materials,this paper studied the relationships of soil microbial biomass carbon(BC) and nitrogen(BN) with soil nitrogen mineralization potential(N0),total nitrogen(TN),organic carbon(OC),and particle composition.The results showed that BC and BN had significant positive correlations with TN and OC,suggesting that BC and BN were highly related with soil fertility and could be used as biological indices of soil quality.BC and BN were highly correlated with N0,with the correlation coefficient being 0.741 and 0.665,respectively(P<0.01).BC,BN,TN,OC and N0 all had significant positive correlations with physical clay(<0.01 mm) but negative correlations with physical sand(>0.01 mm),and had significant positive correlations with the ratio of physical clay to physical sand,indicating that soil organic matter was mainly combined with physical clay to form soil organic-mineral complexes.