福建柏和杉木人工林凋落物分解及养分动态的比较  

Comparatively Study on Litter Decomposition and Nutrient Dynamics Between Plantations of Fokienia hodginsii and Cunninghamia lanceolata

作　　者：杨玉盛[1] 郭剑芬[2] 陈银秀[2] 陈光水[2] 郑燕明[3] 

机构地区：[1]福建师范大学,福州350009 [2]福建农林大学林学院,南平353001 [3]福建农林大学莘口教学林场,三明365002

出　　处：《林业科学》2004年第3期19-25,共7页Scientia Silvae Sinicae

基　　金：教育部骨干教师资助项目和福建省重大基础研究项目 ( 2 0 0 0 -F -0 0 4)

摘　　要：对福建柏和杉木的凋落物分解和N、P、K养分动态进行了为期 75 0d的研究 ,结果表明 :两树种的落叶和落枝分解速率与时间呈指数关系 ,第 1年干重损失率分别为 83 4 7%和 19 4 3% (福建柏 )、6 0 78%和 2 5 0 2 % (杉木 )。落叶分解过程中 ,P浓度增加 ,而K和C浓度下降 ;但落叶N浓度 ,福建柏的先升后降 ,杉木的则单调上升 ;落枝分解过程中各元素浓度均呈现 :N单调上升 ,K和C单调下降 ,P先升后降。落叶和落枝的元素分解速率均以K最大 ,其次为C和P ,N最小。福建柏落叶元素年分解速率 ,N、P和C比杉木的大 ,但K却比杉木的小 ;而福建柏落枝元素年分解速率C和N比杉木的大 ,而P和K却比杉木的小。福建柏落叶和落枝分解过程中N、P、K的年养分释放量分别为 2 6 30、0 16 2和 1 6 0 4g·m- 2 ,分别是杉木 (1 2 0 5、0 14 3和 1 12 9g·m- 2 )的 2 18倍、1 13倍和 1 4 2倍。与杉木林相比 ,福建柏林凋落物分解过程中养分释放量高 ,且养分释放 归还比值亦大 ,表明福建柏林凋落物养分周转比杉木快 ,这对维持林地土壤肥力是有益的。Decomposition of forest litter and simultaneous release of bioelements is one of the fundamental pathway of the flow of nutrient and energy in forest ecosystems. This study was related to rate of litter weight loss and release of nutrient elements in plantations of Fokienia hodginsii and Cunninghamia lanceolata in Fujian. Needles and branches of the two species were involved in the 750 day period of litter bag studies. Litter decay is regulated by an array of factors, of which the two most important are probably climate and the chemical composition of the litter, termed `substrate quality'. N content, C: N ratio, lignin content and lignin: N ratio have been seen to be of critical importance. The high precipitation and temperature of subtropical climates yield a general high rate of decomposition. Rate of weight loss showed exponential relationship with time for litter of needle and branch, with percent initial weight loss of 83.47% and 19.43% for needle and branch litter of F. hodginsii at the first year. The corresponding values were 60.78% and 25.02% for litter of C. lanceolata. Generally, the course of nutrient dynamics during decomposition follows three phases: (1)Initial nutrient release through leaching; (2) Net immobilization when decomposer microorganisms retain or import nutrients, followed by (3) Nutrient release when nutrients are released from the litter at a rate paralleling mass loss. However, this general pattern can vary depending on litter type, species, and ecosystem. For example, in conifers the leaching phase is typically short or absent. In this study, concentration of P in needle litter appeared to increase and concentrations of K and C appeared to decrease during the decomposition, while change of N concentration was different for two types of needle litter, especially in initial phase of decomposition. There was an obvious increase of N concentration at 60 day period followed by a decrease for F. hodginsii, while this pattern was not found for C. lanceolata. As to changes of nutrient con

关 键 词：福建柏 杉木 人工林凋落物 分解 养分释放 森林生态系统生产力 

分 类 号：S791.43[农业科学—林木遗传育种] S791.27[农业科学—林学]