Long-Term Effects of Fertilization on Microbial Biomass and Activities of Red Paddy Soils

Soil microbial biomass and activity are sensitive indices to soil fertility promotion and soil environmental changes. In this paper,the responses of microbial biomass and respiration to the different fertilization managements in paddy soils cultivated from wasteland in red soil region were studied. The results showed that,after 16 years of rice cropping,the microbial biomass of activity of red paddy soils under all fertilizations were still in low level. The fertilization managements affected microbial biomass carbon (MBC) and substrate-induced respiration (SIR) significantly,with the exception of basal respiration (BR). Compared with the no fertilizer treatment (CK),nitrogen and potassium fertilizers did not affect microbial biomass and activity evidently. The microbial biomass,metabolizing activity and temperature sensitivity of microbial respiration were promoted by the application with organic cycling. Among of all fertilization treatments,composed application of chemical fertilizer and organic cycling promoted the soil microbial biomass and metabolize activity most.