桉树人工林生态系统养分循环和平衡研究 Ⅱ.桉树人工林生态系统的养分循环

The nutrient cycling and balance of eucalyptus plantation ecosystem Ⅱ. The nutrient cycling of eucalyptus plantation ecosystem

根据大量的观测分析资料,论述了刚果W5桉树人工林生态系统养分的地球化学循环和生物小循环。研究结果表明,每公顷每年通过地表径流和地下渗漏从生态系统输出的养分质量以K最多,达21.25 kg/(hm2a);其次为N,达17.21 kg/(hm2a)。桉树人工林生态系统养分流通质量的净变化值f(K)、f(Ca)为负值,f(N)、f(P)、f(Mg)为正值;桉树人工林生态系统养分的生物小循环研究表明,在一个轮伐期内,每公顷桉树吸收养分的质量,依次为Ca 429.03 kg/hm2,其次为N 277.01 kg/hm2和K 208.12 kg/hm2。而在一个轮伐期中归还的养分质量,Ca只有99.78 kg/hm2,K为113.04 kg/hm2。在养分循环率方面,与热带半落叶季雨林比较,桉树人工林生态系统的养分循环率要小得多,说明桉树人工林土壤养分趋向于减少。

Based on the large amount of observational and analytical data, the geochemistry cycling and biological minor-cycling of nutrients in eucalyptus plantation ecosystem in Leizhou Peninsula, China, are expounded in this paper. Results show that, the output of K from runoff and leakage is as much as 21.25 kg/(hm2a), followed by N, as 17.21 kg/(hm2a). The calculation of net variation value of nutrient fluxes of the ecosystem shows that f(K) and f(Ca) are negative and f(N), f(P), and f(Mg) are positive. In a felling round, the amount of nutrient uptake by the eucalyptus forest is in the order of Ca (429.03 kg/hm2), N (277.01 kg/hm2) and K (208.12 kg/hm2). While in a felling round, the return of Ca is only 99.78 kg/hm2, and K only 113.o4 kg/hm2. The eucalyptus plantation ecosystem is in the decline of soil nutrients.