Abstract:

Field experiment with barley was conducted to investigate the dynamics of soil microbial biomass C and N as affected by enhanced ultraviolet-B radiation and N supply. The experiment was designed with 2 levels of UV-B radiation and 3 levels of N supply, i.e. 30, 150 and 300 kg N ha-1. The results indicated that, compared with control, enhanced UV-B radiation increased microbial biomass C and N in non-rhizospheric soil, regardless of N supply levels; but decreased microbial biomass C and N in rhizospheric soil, except for low N supply level. Irrespective of UV-B radiation, high N supply level depressed microbial biomass N in rhizospheric soil as well as microbial biomass C and N in non-rhizospheric soil.