川西北森林皆伐迹地和四川嵩草草甸土壤及其草本群落的比较研究

Comparative Studies on Soil and Herbage Community in Clear-cutting Forestlands and Kobresia setchwanensis Meadow in Northwestern Regions of Sichuan Province

通过样方调查,取样地上地下生物量,分析土壤理化性质,对川西北森林皆伐迹地和四川嵩草草甸土壤及其草本群落进行比较研究。结果发现:①森林皆伐迹地土壤的有机质含量、孔隙度、全氮、全磷、全钾和铵态氮高于四川嵩草草甸土壤,硝态氮和容重低于四川嵩草草甸土壤。四川嵩草草甸土壤劣于皆伐迹地,其自然恢复是一个较长期的过程。②森林皆伐迹地的草本群落以禾本科植物为优势种,主要植物是禾本科与杂类草;四川嵩草草甸以莎草科植物为优势种,主要植物是莎草科与杂类草。皆伐迹地的草本群落高度、物种数、Margalef指数和Shannon-W iener多样性指数高于四川嵩草草甸,但密度与物种均匀度低于四川嵩草草甸,皆伐迹地的草本群落不是一个稳定的群落。森林皆伐迹地草本群落与四川嵩草草甸的生物量没有不同。减轻放牧压或进行封育,四川嵩草草甸植被是能够恢复到以禾本科牧草为主的优良草地的。③森林皆伐迹地与四川嵩草草甸草本植物群落优势层片的植物种类不同,群落外貌不同。

Through plots investigation, sampling above-ground and underground biomass, analysis of soil physical and chemical characteristics, this study aimed to conduct comparative studies on soil and herbage community in clear-cutting forestland and Kobresias setchwanensis meadow in northwestern regions of Sichuan Province. The results showed that （1） The content of organic matter, porosity degree, total N, total P, total K and NH -N in clear-cuttiag forestland soil were higher, hut the.content of NO3^- -N and bulk density were lower. The physical and chemical characteristics of soil in K. setchwanensis meadow was worse than that of K. setchwanensis meadow soil, whose natural restoration needed a long time; （2） Gramineous plants in clear-cutting forestland were dominant species, whose primary plants were gramineae and forbs. Sedge plants in K. setchwaneusis meadow were dominant species, whose primary plants were sedge and forbs. Herbage community height, specie numbers, Margalef index and Shannon-Wiener diversity index in clear-cutting forestland were bigger, individual density and specie uniformity degree in clear-cutting forestland were smaller and the herbaceous community in clear-cutting forestland was not a steady community. Community biomass in clear-cutting forestland and K. setchwaneusis meadow were not different, and K. setchwanensis meadow was able to recover as a fine meadow with gramineous plants as dominant species after lower grazing or stop grazing; （3） Plant species and community appearance in the dominant synusia of herbage community in clear-cutting forestland and K. setchwanensis meadow were different.