禾-豆混播草地种间竞争与共存  

Coexistence and inter-specific competition in grass-legume mixture

作　　者：王平[1] 周道玮[2] 张宝田[3] 

机构地区：[1]东北师范大学城市与环境科学学院国家环境保护湿地生态与植被恢复重点实验室,长春130024 [2]中国科学院东北地理与农业生态研究所,长春130012 [3]东北师范大学草地科学研究所植被生态科学教育部重点实验室,长春130024

出　　处：《生态学报》2009年第5期2560-2567,共8页Acta Ecologica Sinica

基　　金：国家重点基础研究发展规划资助项目(G2000018602);东北师范大学自然科学青年基金资助项目(20050401)

摘　　要：以羊草分别与沙打旺、兴安胡枝子、花苜蓿、紫花苜蓿、山野豌豆5种豆科牧草在混播数量比为1∶0、2∶1、1∶2、0∶1的条件下建立两物种混播草地,以相对产量、相对密度和相对产量总值为指标,比较各个混播草地中种间竞争的相对激烈程度;各个物种组合的种间竞争优势以及是否发生氮素资源分离;并探索不同禾-豆混播群落达到共存状态的可能途径。研究结果表明,各个禾-豆组合的相对产量总值分别在不同收获时期大于1,禾草与豆科牧草的生态位发生了不同程度的分离。沙打旺和紫花苜蓿对羊草具有显著的竞争优势,即使其种内竞争大于种间竞争时,混生的羊草亦受到强烈的种间竞争压力。与此相反,羊草对兴安胡枝子、花苜蓿和山野豌豆具有种间竞争优势。刈割对竞争双方的优劣地位产生很大影响,减少强竞争力物种的混播比例,可促进混播物种双方均受益,形成共存格局。实验采用的相对密度指标在预测未来混播种群组成上比相对产量更为可行,并且具有维持低个体大小、高构件密度能力是竞争关系中忍耐型物种能够长期存在的可能原因之一。This research measured the relative intensity of inter-specific competition, competitive superiority and nitrogen resource separation in five grass-legume combinations： Leymus chinensis-Astragalus adsurgens; L. chinensis- daurica; L. chinensis-Medicago ruthenica; L. chinensis-M, sativa cv. Aohan; L. chinensis-Vicia amoena at four seeding ratios： 1：0, 2：1, 1：2, 0：1. Relative yield （RY）, relative density （RD） and relative yield total （RYT） were used to determine competition performances and coexistence for different grass-legume mixtures. RYT of each combination was bigger than 1 at different times, indicating niche separation likely occurred between grass and legumes. Even though intra- specific competition intensity was bigger than inter-specific, A. adsurgens and M. sativa cv. Aohan had competitive superiority when in competition with L. chinensis. Conversely, L. chinensis showed competitive superiority when growing with L. daurica, M. ruthenica, or V. amoena. Defoliation significantly affected the competitive superiority of the dominant species. Reducing the proportion of high competitive species in seed mixtures could enhance the likelihood of coexistence. The RD used in this experiment is a better predictor than RY for community structure of grass-legume mixtures. The ability to maintain lower individual biomass with higher module density was one of the putative mechanisms for species coexistence in this study.

关 键 词：种内竞争 种间竞争 相对产量 相对密度 相对产量总值 

分 类 号：S812[农业科学—草业科学]