Abstract: The study on the dynamics of red soil microbial biomass C in tea garden after 4 years different fertilization showed that straw mulching combined with applying organic manure and chemical fertilizer, intercropping white clover, and applying chemical fertilizer could all increase the amount of soil microbial biomass C significantly. The annual variations of soil microbial biomass C all presented the tendency of low-high-low-high, and the effects of fertilization varied with different periods. The annual average of soil microbial biomass C in treatments T₁ (straw mulching+100% organic manure), T₂ (straw mulching+75% organic manure +25% chemical fertilizer), T₃ (straw mulching+50% organic manure +50% chemical fertilizer), T₄(straw mulching+25% organic manure +75% chemical fertilizer), T₅ (100% chemical fertilizer) and T₆ (intercropping white clover) were 17.05%, 32.38%, 32.05%, 24.30%, 26.23% and 24.63% higher than CK, respectively, and the differences were significant (P<0.05). Soil microbial biomass C had significant positive correlations with soil active organic matter, total nitrogen, and microbial biomass N and P, but no significant correlations with soil available nitrogen, total phosphorus, total potassium, and moisture content. In comparing with applying chemical fertilizer or organic manure alone, their combination was more advantageous in improving soil fertility.

Key words: Brachionus calyciflorus, Strain, Filtration rate, Ingestion rate, Algae food