喀斯特地区红三叶混播草地群落对长期适度放牧的响应  

Responses of Trifolium pratense mixed communities to long-term moderate grazing in Karst region

作　　者：王元素[1] 洪绂曾[1] 蒋文兰[2] 王堃[1] 

机构地区：[1]中国农业大学动物科技学院草地所,北京100094 [2]甘肃农业大学草业学院,甘肃兰州730070

出　　处：《生态环境》2007年第1期117-124,共8页Ecology and Environmnet

基　　金：国家"九五"重大科技攻关项目(96-016-02-01);国家"975"项目(G2000018606)

摘　　要：群落稳定性的生态学研究一直缺乏动物利用条件下的长时间梯度田间试验，而混播草地的放牧利用年限是生态脆弱的南方喀斯特山区生态环境建设和资源可持续利用的关键问题之一。用考力代绵羊轮牧，在牧前和牧后草地现存最（干物质，DM，drymatter）分别为1800-2500（草层高15～18cm）和900--1200kg·hm^-2（草层高3～5cm）的适度放牧利用条件下，对亚热带最常见的豆科牧草红三叶（Trifolium pratense）与禾本科牧草的两两混播草地的群落生产力和持久性开展长期研究。20年的结果表明：适度放牧利用下，群落地上总生物量长期稳定，各组合间差异不显著，总盖度20a后仍高达97％以上；适度放牧有利于牧草的生产力持久性，红三叶、鸭茅（Dactylis glomerata）、多年生黑麦草（Lolium perenne）和黑穗画眉草（Eragrostis nigra）都在群落中长期存在；群落净产量和持久性是尺度依赖的，群落长期净生产力以红三叶＋鸭茅的最高（DM产量353.3g·m^-2．a^-1）（P〈0．05），对杂草侵入的抵抗力最强，而前10a红三叶＋多年生黑麦草有很高的净生产力（DM产量449．8g·m^-2．a^-1）：物种的生产力受伴生种的影响，前10a红三叶在与无芒雀麦（Bromus inermis leyss）和黑穗画眉草组合中的产量高于其它组合（P〈0．05）；不同的物种侵占力不同，栽培种侵占力最强的是黑穗画眉和鸭茅，非栽培种侵占力最强的是白三叶。Long temporal controlled field study with herbivorous animal is essential to investigate the productivity and stability of plant community. Persistence of grazing mixed pasture has been a key issue in environment conservation and sustainable utilizing of resources in karst region. Under moderate grazing with Corriedale sheep, the productivity and botanical composition of Trifolium pratense mixtures were studied over a 20-year period in karst region of southwest China. Four mixtures consisted of Trifolium pratense plus Lolium perenne （VT＋L）, Dactylis glomerata （VT＋D）, Bromus inermis leyss （VT＋B） and Eragrostis nigra （VT＋E）. The pastures were grazed between 1 800--2 500 kg·hm^-2 and 900-1200 ·kg·hm^-2 in terms of DM （dry matter）. The results indicated that moderate grazing facilitates the persistence of total yields of all mixtures with a high total cover above 97%, and extends the existence of T. pratens, D.glomerata, L.perenne and E.nigra. However, the ANPP （above ground net primary production） is temporal scales-dependent. VT＋D is the most productive with 353.30 g·m^-2·a^-1 in ANPP over 20 year, while VT＋L produced high ANPP in the early 10 years. The production of T. pratense is affocted by the companion grass. For the aggression abilities of cultivated species, E. nigra is the most aggressive, followed by D.glomerata, whereas Trifolium repens is the most aggressive among non-cultivated species invaded into each mixture by above 20% cover.

关 键 词：喀斯特地区 红三叶 混播群落 总生物量 盖度 持久性 相容性 侵占力 

分 类 号：S872.8[农业科学—畜牧兽医] Q948[生物学—植物学]