不同放牧梯度下高寒小嵩草草甸植被根系和土壤理化特征的变化  

Vegetation roots and soil physical and chemical characteristic changes in Kobresia pygmaca meadow under different grazing gradients

作　　者：王长庭[1] 王启兰[1] 景增春[1] 冯秉福[2] 杜岩功[1] 龙瑞军[3] 曹广民[1] 

机构地区：[1]中国科学院西北高原生物研究所,青海西宁810001 [2]青海畜牧兽医职业技术学院,青海湟源812100 [3]兰州大学草地农业科技学院,甘肃兰州730070

出　　处：《草业学报》2008年第5期9-15,共7页Acta Prataculturae Sinica

基　　金：国家自然科学重点基金项目(30730069);中国科学院野外台站基金项目资助

摘　　要：以野外样地调查和室内分析法研究了不同放牧梯度下高寒小嵩草草甸的植被根系空间变化和土壤环境因子间的关系。结果表明，放牧干扰不仅改变了高寒小嵩草草甸植被根系分布、根土比例，改变了植物群落的结构和功能，而且使土壤的物理和化学特性发生了明显的改变。随着放牧强度的增加，蕴育土壤根系的基质量逐渐减少，根土比特别是0～10cm土层的根土比例增加；“载体”量减少导致大部分地下根系由于营养供给水平的降低而死亡，归还土壤中有机质的数量逐渐减少；不同放牧梯度下，植被根系（0～40cm）的垂直分布、根土比与土壤容重、土壤含水量以及土壤中全氮、硝态氮和铵态氮含量存在一定的相关性；放牧主要通过影响土壤环境及其养分含量来改变草地群落生物量（地上、地下）。Field surveys and experimental analysis were used to detect the relationship between spatial changes of vegetation roots and soil environmental factors under different grazing gradients in an alpine meadow. The experimental plots were located in the Haibei alpine meadow ecosystem research station. There were obvious changes of root distribution in the Kobresia pygrnaca meadow community, in the soil quantity attached to roots, the ratio of roots to soil weight, the variation of plant community structure and function, and in the change of soil physics and chemistry characteristics under grazing disturbance. With increased grazing intensity the ratio of roots to soil in the 0-10 cm soil layer was enhanced as the quantity of soil gradually decreased. Most rhizomes died because the ability of soil to supply resources decreased thus return of soil organic matter to the soil decreased, and sustainable utilization of vegetation was reduced resulting in converse succession （or degenerate succession） in the grassland. The effects of soil bulk density, soil moisture, total N, NO3^--N, and NH4^＋ -N contents on vertical distribution of vegetation roots （0-40 cm） and ratio of roots to soil in different grazing gradients were more significant than those of other soil properties. The soil environment and nutrients were influenced by grazing which changed the grassland community biomasses （both above and below-ground biomass）.

关 键 词：放牧梯度 植被根系 土壤环境 高寒草甸 根土比 

分 类 号：S812[农业科学—草业科学]