[Effects of specific microbial biocides on N transformation in soil with glucose amendment]

In an incubation test of soil with glucose amendment, two kinds of nitrogenous fertilizer and three kinds of specific microbial biocides were applied, and the contents of soil NH(4+)-N, NO3(-)-N, glucosamine and muramic acid were measured to differentiate the relative contribution and timing characteristics of soil microbes in nitrogen immobilization. The results showed that penicillin and streptomycin decreased the transformation rate of NH(4+)-N markedly, with more significant effects than actidione. The amount ratio of glucosamine to muramic acid after applying penicillin and streptomycin rapidly increased first, and tended to equilibrium then. With the application of actidione, the transformation rate of NO3(-)-N decreased continuously, and the synthesis of glucosamine was inhibited, while penicillin and streptomycin had no significant effects on them. At the early stage of incubation, bacteria could rapidly immobilize both NH(4+)-N and NO3(-)-N, with NH(4+)-N preferred, while at the later stage of incubation, fungi were the dominant contributor to nitrogen transformation, and had much stronger ability of utilizing NO3(-)-N than bacteria.