喀斯特石漠化生态系统恢复演替过程中土壤质量特性研究——以广西都安县澄江小流域为例

采用空间序列代替时间序列的方法,以广西都安县澄江小流域为例,研究广西喀斯特山区石漠化生态系统恢复演替过程中土壤质量的变化特征.在研究区内选择石漠化恢复演替的8个阶段,即石漠化土地、坡耕地、矮草丛、高草丛、灌草丛、灌丛、人工恢复乔木林、自然恢复乔木林的典型样地,对土壤化学和生物学性状进行了比较研究,以探讨石漠化生态系统恢复演替过程中土壤质量的修复状况.结果表明:不同的演替阶段导致了土壤化学和生物学性质的显著差异,而且在植被向更高一级阶段发展过程中土壤各项指标都得到提高,土壤质量总体呈现改良的态势.随着植被演替的正向进行,土壤质量指数呈增长趋势,不同演替阶段土壤质量综合指数分别为:石漠化土地,134.78;坡耕地,192.24;矮草丛,235.18;高草丛,260.67;灌草丛,317.89;灌丛,359.80;人工恢复乔木林,363.39;自然恢复乔木林,460.77.自然植被的正向演替是提高土壤质量的有效途径,恰与石漠化过程相反.

Quality Characteristics of Soils in Karst Rocky-Desertified Areas With Ecosystem Under Restoration Succession-A Case Study of Chengjiang Subwatershed,Du'an County,Guangxi

Quality characteristics of soils in rocky-desertified areas with ecosystem under restoration succession in Karst regions of Guangxi were studied using spatial sequence instead of temporal one.The Chengjiang Subwatershed in Du′an County,Guangxi was selected as a subject of the study.Sampling sites typical of the eight phases of the restoration succession,i.e.rocky-desertified land,cultivated slopeland,shortgrass land,tall-grass land,shrub-grass land,shrubbery land,artificial arbor forestland,and natural arbor forestland,were picked out in the subwatershed for comparative study of chemical and biological properties of the soils with a view to exploring how soil quality was remedied in the process.Results show soils differed sharply in chemical and biological properties between the phases.With vegetation developing into a higher phase,soil quality on the whole displayed a trend of improvement and so did its various quality indexes.When the vegetation restoration succession went on,soil quality index presented a rising trend,i.e.rocky-desertified land (134.78),cultivated slopeland (192.24),shortgrass land (235.18),tall-grass land (260.67),shrub-grass land (317.89),shrubbery land (359.80),artificial arbor forestland (363.39),and natural arbor forestland (460.77).Positive evolution of natural vegetation is an effective path towards better soil quality and an outright reverse process of rocky desertification.