茂兰喀斯特原生林不同坡向及分解层的凋落物现存量和养分特征  

Litter stock and nutrient characteristics of decomposing litter layers in Maolan Karst primary forest in different slope directions

作　　者：赵畅 龙健[1] 李娟[2] 廖洪凯[1] 刘灵飞[1] 张明江 华健 

机构地区：[1]贵州师范大学贵州省山地环境重点实验室,贵阳550001 [2]贵州师范大学地理与环境科学学院,贵阳550001

出　　处：《生态学杂志》2018年第2期295-303,共9页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(41661045;41601249;414601072;31360121)资助

摘　　要：以茂兰喀斯特原生林3种坡向林下凋落物为研究对象,通过野外调研采样和室内分析测试相结合的方法,探讨了不同喀斯特原生林生态系统下坡向和分解层的凋落物现存量、主要营养元素含量、储量及元素释放率的分布特征。结果表明:1)阴坡凋落物现存总量((0.568±0.024)kg·m^(-2))高于阳坡((0.504±0.03)kg·m^(-2))和半阴坡((0.295±0.02)kg·m^(-2)),不同坡向林下凋落物现存量在各分解层均表现为:未分解层(L层)>半分解层(F层)>全分解层(Y层);2)不同坡向林下凋落物各营养元素平均含量表现为:C((388.7±11.2)g·kg-1)>N((24.90±3.49)g·kg-1)>K((9.78±1.82)g·kg-1)>P((1.53±0.32)g·kg-1),在各分解层的含量表现不同,碳含量和钾含量:L>F>Y,氮含量和磷含量:Y>F>L;3)3种坡向林下凋落物的碳、氮、钾元素总储量表现为:阴坡>阳坡>半阴坡,磷元素总储量表现为:阳坡>阴坡>半阴坡;4)凋落物营养元素储量在L层占总储量的37.1%~64.2%,并随分解加剧而减少;L层和F层的元素释放率均表现为:阴坡>半阴坡>阳坡,且碳、钾元素释放率高于氮、磷元素。在喀斯特原生林凋落物分解的养分释放过程中,坡向对林下凋落物的理化性质及分解速率有较大影响,且阴坡林下凋落物分解较快、营养元素内部循环周期较短。In the present study, we selected forest floor litters from three slope directions in Maolan Karst primary forest to investigate the distribution characteristics of litter stock, nutrient contents （C, N, P and K） and their release rates of different decomposing layers. The results showed that： （1） Total litter stock was higher in north slope （0.568 kg · m-2） than that in south slope （0.504 kg · m-2） and northeast slope （0.295 kg · m-2）. Litter stocks in different layers arranged in the order of fresh litter layer （layer L） 〉 fragmented litter layer （layer F） 〉 fully decomposed layer （layer Y） ; （2） The C and K contents in different decomposing layers were in the order of layer L〉layer F〉layer Y, whereas the N and P contents were followed by the order of layer Y〉 layer F〉 layer L. （3） Total storage of litter C, N and K was in the order of north slope 〉south slope〉northeast slope, and total litter P storage was the highest in the south slope, followed by north slope, and then the northeast slope. （4） The litter nutrient storage in layer L accounted for 37.1% to 64.2% of the total nutrient storage, showing a decrease trend with the increases of decomposition degrees. The release rates of the nutrient elements in layers L and F were the highest in the north slope, followed by the northeast slope and the south slope. Moreover, the release rates of C and K were higher than that of N and P. Our results indicated that the slope direction had a great influence on the chemical properties and decomposition rate of litters. In general, litters in the north slope decomposed rapidly and the cycling time of nutrient elements was shorter than that in other slopes in the Karst primary forest.

关 键 词：喀斯特原生林 坡向 凋落物 现存量 养分特征 

分 类 号：S714[农业科学—林学]