喀斯特地区三叶草混播草地群落组分20年动态

三叶草（Trifolium）混播草地群落持久性研究对喀斯特草地建设与石漠化治理具有重要意义。在威宁灼圃示范牧场开展的由白三叶（T. repens）、红三叶（T. pratense）、无芒雀麦（Bromus inermis）、紫羊茅（Festuca rubra），分别加上多年生黑麦草（Lolium perenne）、鸭茅（Dactylis glomerata）、黑穗画眉草（Eragrostis nigra）、鹅冠草（Elymus kamoji）组成4个5组分混播草地，在绵羊适度放牧下测定牧前、牧后草地现存量，连续进行20年持久性研究。结果表明：时间及组合×利用时间的交互作用对所有混播组合影响极显著，而组合间产量差异不显著，其动态变化与年降水量的动态变化之间无显著的对应关系，但同物种在各混播群落中的生产力和稳定性差异明显，说明各组分之间存在显著的生态位互补和竞争共存关系。各物种中生产力与稳定持久性最好的是紫羊茅和白三叶，其次是多年生黑麦草和鸭茅，最差的是无芒雀麦和鹅冠草；而在草地建植初期表现最好的是多年生黑麦草和红三叶。

Dynamics of Community Composition of Mixed Clover-grass Pasture during 20 Years in Karst Region,Southwest China

Mixed clover-grass pasture plays an important role in grassland restoration and rocky desertification control in karst region. The persistence of mixed clover-grass pasture has been investigated for 20 years in Zhuopu Demonstration Farm, Guizhou Province. Pasture coverage was measured under moderate sheep grazing. Results showed that both years and compositions of pasture had significant effects on the net production of pasture, whereas the yields of different treatments had no significant difference. There was no significant correlation between net production and annual precipitation. Meanwhile, different species had different productivities and stabilities. Ryegrass and red clover produced high yields in earlier years after establishment.