锐齿栎林营养元素生物循环的研究

A Study on Nutrient Biocycling of Sharptooth Oak Stand in Qinling Mts.

对秦岭26 龄天然锐齿栎次生林包括0～60 cm 土层中营养元素进行了测定,其总贮量达390.173 9 t/hm 2,土壤、乔木、灌木、草本和凋落物各层营养元素现存量分别为387.786×103、2 139.225、71.971、18.050 和158.944 kg/hm 2。植被中营养元素的积累量为2 229.24kg/hm 2,乔木、灌木、草本等层次分别占96.0% 、3.2% 和0.8% 。凋落物中枯枝、分解落叶和未分解落叶营养元素的积累量分别占总量的15.0% 、46.5% 和38.5% ,且各营养元素的含量和积累量均不相同。生态系统0～60 cm 土层中N、P、K、Ca、Mg 的现存量分别占总量的4.3% 、0.8% 、20.2% 、37.0% 、37.8% ;土壤中的有效N、P、K 分别为1.441 7、0.024 5 和54.998 6 t/hm 2。系统营养总量的排序:Mg> Ca> K> N> P,而植物及凋落物中的排序为:Ca> N> K> Mg> P。该林分营养元素的年吸收量、年存留量和年归还量分别为334.374、138.870 和195.502 kg/hm 2,各个营养元素归还率不同,Mg 的最大为0.660,K的最小是0.445,平均值为0.585。

The natural secondary sharptooth oak stand with the age of 26 in Qinling Mts. including soil layer(0～60cm) totally contained nutrient elements 390.173 9 t/hm 2, among them the soil, arbor, shrub, grass and litter possessed nutrient elements 387.786×10 3, 2 139.225 ,71 971,18.050 and 158.944 kg/hm 2 respectively. The vegetation had nutrient store 2 229.246 kg/hm 2 with the different layers of arbor 96.0%, shrub 3.2% and grass 0 8%, the percentages of nutrient allocation among the different layers had marked difference. The amounts of nutrient accumulations of falling branches, decomposed falling leaves and undecomposed falling leaves were 15.0%, 46.5% and 38.5% of the total respectively, among them there were different nutrient percentage and accumulation contents. The contents of N,P,K, Ca and Mg in the soil layer(0～60cm) of standing crop were 4.3%,0.8%,20 2%,37.0% and 37.8% of the total respectively, the amounts of effective N, P and K were 1.441 7,0.024 5 and 54.998 6 t/hm 2 respectively. The relative amounts of nutrient elements in the ecosystem were Mg>Ca>K>N>P, but those in the vegetation and litter were Ca>N>K>Mg>P. The annual uptake, store and return of the nutrient elements were 334.374, 138.870 and 195.493 kg/hm 2 respectively. Different nutrient elements had different return ratio, Mg to the maximum at 0.660, K to the minimum at 0.445 and average value 0 585.