天祝高寒草地植被、土壤及土壤微生物时间动态的比较  

Temporal changes of grassland vegetation,soil and soil microbial population in the Tianzhu alpine region

作　　者：姚拓[1] 王刚[2] 张德罡[1] 龙瑞军[1] 

机构地区：[1]甘肃农业大学草业学院,兰州730070 [2]兰州大学干旱农业生态国家重点实验室,兰州730000

出　　处：《生态学报》2006年第6期1926-1932,共7页Acta Ecologica Sinica

基　　金：中国博士后科学基金资助项目(2004035176);甘肃省科学技术攻关资助项目(2GS035-A41-001-04);国家科技攻关计划课题资助项目(2002BA901A29)~~

摘　　要：对天祝高寒草地21a前（1982年）、后（2003年）植被状况、土壤理化性质、土壤三大类微生物（细菌、放线菌和真菌）和各生理群微生物（硝化细菌、好气性固氮菌和好气性纤维素分解菌）及不同退化程度（围栏内、围栏外和鼠丘地）草地土壤微生物数量变化特点进行了对比研究。结果表明：（1）与1982年相比，目前该区天然草地植被总盖度、主要优良牧草种类、产草量等显著下降，草地植被退化明显；（2）草地土壤pH升高，土壤含水量、有机质、氮、磷含量均下降，草地土壤理化性质劣于1982年；（3）目前该区天然草地土壤三大类微生物数量及各生理群微生物数量变化十分明显，1982年土壤细菌、放线菌和真菌及微生物总数分别是2003年的153．6、5．5、4．1倍和151．2倍；土壤硝化细菌、好气性固氮菌和好气性纤维素分解菌数量分别是2003年的5．7、43．3倍和94．4倍；（4）轻度退化草地（围栏内）土壤各类微生物数量明显高于严重退化草地（围栏外、鼠丘地），其数量前者一般为后者的1．5—4．5倍。Sustained overgrazing and rodent＇s destruction are responsible for the degradation of more than 50% of grassland in north-western China. In fact these persistent adverse effects caused a reduction in the number of high quality forage species and grassland productivity, accompanied with an increase in the incidence of weed and poisonous plants. The degradation of the grassland ecosystem causes serious social and economical problems in the region. To prevent and control grassland degradation,intensive muhidisciplinary research projects have been performed in this area. However information on the microbial population changes in the grassland is scarce. Soil microbial activity plays an important and vital role in grassland ecosystem because it affect soil physical properties like the stability of aggregates, soil aeration and water holding capacity, and it is responsible of the mineralization and recycling of several important nutrients like carbon, nitrogen and phosphorus. Soil organic matter is also significantly affected by microbial activity. Thus, grassland soil microbial importance and diversity can be used as an index of grassland health and soil fertility. The present work was performed in the alpine region of Tianzhu, eastern part of the Qinghai-Tibetan Plateau, which is characterized by high altitude, important daily temperature variations with sparse air, strong radiation and low temperature. We studied the temporal changes in vegetation and soil properties, the different physiological groups of soil microorganisms and the effect of the degree of grassland deterioration on soil microbes, by comparing measurements made in 1982 with those made in 2003. In general, the vegetation condition as well as soil physical and chemical characteristics were obviously in better condition in 1982 as compared to 2003. In 2003, the parameters showing important decreases as compared to 1982, included： the dominant plant species of the vegetation coverage, forage yield, soil water content, soil organic matter, N and P co

关 键 词：高寒草地 植被 土壤 微生物数量 时间动态 天祝 

分 类 号：S812[农业科学—草业科学]