桂西南喀斯特山地主要植被类型凋落物累积量及其持水特性

Litters accumulation under forests in karst mountain area in southwest Guangxi and theirs water-holding characteristics

基于野外实地调查与室内浸水法,对桂西南喀斯特山地5种具有代表性的植被类型(灌丛林、灌木林、乔灌过渡林、蚬木林和仪花林)林下凋落物的蓄积量进行了研究,并对各植被类型的持水特性和拦蓄能力进行对比研究。结果表明:不同植被类型的凋落物蓄积量变幅在2.73～4.59 t.hm-2之间,从大到小排列为:蚬木林>乔灌过渡林>仪花林>灌丛林>灌木林,差异显著(P<0.05)。自然含水率和最大持水率的变幅分别为15.47%～36.36%和128.23%～168.36%,差异极为显著(P<0.01)。蚬木林的自然含水量最大,仪花林则最小;灌丛林的最大持水率最大,仪花林最小。各植被类型凋落物的最大持水量之间差异不显著(F=1.540,P=0.211>0.05),蚬木林最大,仪花林最小。最大拦蓄率和有效拦蓄率变化范围分别在95.13%～147.49%和75.41%～122.77%之间,差异极为显著(P<0.01),灌木林最大,蚬木林最小;最大拦蓄量和有效拦蓄量变幅分别在377.55～520.62 t.hm-2和313.54～430.74 t.hm-2之间,差异不显著(P>0.05),乔灌过渡林最大,蚬木林其次,仪花林最小。凋落物的蓄积量、持水特性和拦蓄能力因植被类型不同而存在差异。

Through field survey and by using laboratory soaking extraction,the litters accumulation under the five forests（scrub forest,shrub,forest-shrub transition,Excentrodendron hsienmu forest and Lysidice rhodostegia forest）,which are the representative vegetation types in karst mountain area in southwest Guangxi,and theirs water holding characteristics and water retaining capacity were studied.The litters accumulations under the 5 types forests ranged from 2.73 to 4.59 t.hm-2,and in the order of E.hsienmu forest forestshrub transition L.rhodostegia forestscrub forestshrub,there were significant differences among different types forests（p 0.05）.The natural water content rate and maximum water content rate of the litters were 15.47% ～ 36.36% and 128.23% ～ 168.36%,respectively,the differences among the forests were very remarkable（p 0.01）.The natural water content rate of litters in E.hsienmu forest was the highest and that of in L.rhodostegia forest was the lowest,while the maximum water content rate in scrub forest was the highest and that of in L.rhodostegia forest was the lowest,too.The maximum water-holding capacity of litters had no significant difference among the 5 forests（F = 1.540,P = 0.211 0.05）,being the highest for E.hsienmu forest and the lowest for L.rhodostegia forest.The maximum and effective retain rate of litters were 95.13% ～ 147.49% and 75.41% ～ 122.77%,respectively,being the highest for shrub and the lowest for E.hsienmu forest.The differences among forests was remarkable（P 0.01）.The maximum and effective retain capacity of litters were 377.55 ～ 520.62 t.hm-2and 313.54 ～ 430.74 t.hm-2,respectively,had no significant differences among the forests（P 0.05）,being the highest for forest-shrub transition,the second for E.hsienmu forest and the lowest for L.rhodostegia forest.There were differences in accumulation amount,waterholding characteristics and retain capacity of litters among different types vegetations.