Abstract: We used rapeseed oil cake and wheat bran as the main substrates to optimize the solid-state fermentation conditions of Trichoderma longibrachiatum fertilizer by measuring spore germination of T. longibrachiatum under different conditions. We treated 2-year-old Phoebe bournei seedlings with T. longibrachiatum fertilizer and with equal amounts of sterilized fertilizer fermentation substrate as control, and examined the growth, physiology and soil nutrients of P. bournei seedlings after 60 d conventional management in greenhouse. The results showed that after 4 d fermentation under the optimized conditions of 7∶3 ratio of rapeseed oil cake to wheat bran, pH 6, 25 ℃, solidliquid ratio of 1∶3, initial inoculum of 0.5×10⁸ cfu·g^-1 and full light, the spore concentration of T. longibrachiatum reached 1.38×10⁹ cfu·g^-1. The T. longibrachiatum fertilizer effectively enhanced growth indices of P. bournei seedlings, including seedling height, wet weight, dry weight, leaf area, root length, and root activity. Moreover, T. longibrachiatum fertilizer improved rhizosphere soil fertility of P. bournei seedlings, including total nitrogen, total phosphorus, available phosphorus, available potassium, hydrolyzed nitrogen, organic matter contents, and enzyme activities. T. longibrachiatum biological fertilizer can obviously promote the growth and physiological activity of P. bournei seedlings and rhizosphere soil fertility.

Key words: Trichoderma longibrachiatum, biological fertilizer, Phoebe bournei, rap oil seedcake, promoting growth, soil fertility.