关键词: 特征根回归, 天敌-褐飞虱复合种群, 捕食量

Abstract: Mixed Phyllostachys pubescens forest has high productivity and good ecological functions, which is possibly related to the nutrient return characteristics of mixed litter. By using litterbag method, a one-year experiment was conducted to study the decomposition characteristics of different proportion mixed P. pubescens leaf litters in P. pubescens forest in the Yangkou National Forest Farm, Fujian Province of Southeast China. Five treatments were installed, i.e., pure P. pubescens leaf litters (Ⅰ), P. pubescens+Phoebe bournei litters (mass ratio 8:2, Ⅱ), P. pubescens+Cunninghamia lanceolata litters (8:2, Ⅲ), P. pubescens+P. bournei litters (5:5, Ⅳ), and P. pubescens+C. lanceolata litters (5:5, Ⅴ). The litter decomposition rates of different treatments were all compatible with the exponential decomposition model of Olson (R²>0.92, P<0.01). The decomposition rate in treatmentsⅠand Ⅱwas significantly higher than that in other treatments, and the coefficient of decomposition was in the order of Ⅱ >Ⅰ > Ⅲ > Ⅴ > Ⅳ, being 0.68, 0.66, 0.58, 0.55, and 0.49, respectively, which illustrated that only appropriate proportions of mixed tree species leaf litters could promote the litter decomposition. The litter of mixed bamboo-broadleaved forest had higher decomposition rate than that of mixed bamboo-conifer forest. Therefore, the mixed bamboo-broadleaved forest could benefit the persistent productivity of bamboo forest. During decomposition, the N, P, and K in the litters had different release patterns. The N followed the pattern of alternate enrichment and release; the P was rapidly enriched in the first four month, released from the fourth month to fifth month, and then enriched; the K was released in the first three months, and then enriched. The nutrient return of the litters was closely related to the nutrient contents of the litters. The litter C/N ratio and P content could be the key indices for the litter decomposition.

Key words: Latent root regression, Natural enemy brown planthopper complex population, Predation quantity