摘要
以石羊河上游旱泉沟流域紫花苜蓿人工草地为例,采用常规群落学调查,并结合2003-2009年连续7a的定位观测资料,研究了紫花苜蓿草地退化过程和群落动态特征。结果表明：紫花苜蓿人工草地建植以来,群落盖度逐年下降,群落密度逐年增大,地上部分生物量呈抛物线变化趋势;随着紫花苜蓿草地的退化,杂类草侵入群落,物种数由7种增加到17种,且以菊科植物占据优势;建植第5年,草地裸斑增加、质量下降,紫花苜蓿的优势地位明显下降,而赖草成为群落的优势种群。紫花苜蓿退化草地群落动态可分为3个阶段：即紫花苜蓿草地阶段、紫花苜蓿草地向天然草地演替的过渡阶段和禾本科次生草地阶段,人工草地向地带性天然草地的演化迹象明显。
In order to study the degradation process and community dynamics of alfalfa（Medicago sailva） grassland in the alpine areas of NW China,we surveyed alfalfa grassland communities in the Hanquangou valley in the upstream area of the Shiyang River from 2003-2009.The results showed that,the community coverage decreased,the community density increased,the aboveground biomass varied with the single peak curve during planting the alfalfa.With the weeds invading grassland communities,the number of species increased from 7-17 during 7 years,and the Compositae species took dominant proportion.Alfalfa showed natural thinning after 5 years,the grassland quality declined,so parts of the alfalfa grasslands lost utilization value,and Leymus secalinus become the dominant species.The degradation process of alfalfa grassland could be divided into three stages,i.e.,alfalfa grassland stage（2003-2004）,transitional stage from alfalfa grassland to natural grassland（2005-2007）,and secondary natural grassland stage dominated by grasses（2008-2009）,they indicated early phase,medium phase and late phase,respectively.
出处
《干旱地区农业研究》
CSCD
北大核心
2011年第4期228-232,共5页
Agricultural Research in the Arid Areas
基金
国家自然科学基金项目(40971039)
甘肃省科技支撑计划项目(1011FKCA157)
甘肃省高校基本科研业务费用
关键词
紫花苜蓿
退耕地
群落动态
功能群
石羊河上游
alfalfa
abandoned land
community dynamics
functional group
upstream area of the Shiyang River
