无芒雀麦和紫花苜蓿在(1:1)混播中的竞争与共存  

Competition and Coexistence of Alfalfa(Medicago sativa L.) and Smooth Brome(Bromus inermis Layss.) in Mixture

作　　者：谢开云[1,2] 张英俊[2] 李向林[1] 何峰[1] 万里强[1] 王栋[1] 秦燕[1] 

机构地区：[1]中国农业科学院北京畜牧兽医研究所,北京100193 [2]中国农业大学动物科技学院,北京100193

出　　处：《中国农业科学》2015年第18期3767-3778,共12页Scientia Agricultura Sinica

基　　金：国家"十二五"科技支撑计划(2011BAD17B01);国家牧草产业技术体系(CARS-35);中国农业科学院基本科研业务费(2012cj-09)

摘　　要：【目的】在豆科与禾本科牧草混播草地中不仅存在种内竞争也存在种间竞争,由于不同植物之间竞争力强弱不同,竞争的结果将出现一方逐渐消退,另一方逐渐占据优势的现象,因此研究豆科与禾本科牧草之间竞争与共存机制对于维持混播草地稳定高产具有重要意义。【方法】在温室栽培条件下设置3个氮肥水平(0,75,150kg N·hm-2,记作N0,N75,N150)以及单播和混播两种种植模式(无芒雀麦单播,紫花苜蓿单播,无芒雀麦和紫花苜蓿1﹕1混播),采用相对生物量(RY)、相对密度(RD)、竞争率(CR)和相对产量总值(RYT)以及紫花苜蓿的固氮比例(%Ndfa)和转氮比例(%N Trans)等指标研究无芒雀麦和紫花苜蓿在1﹕1混播中的竞争关系与共存机制。【结果】施氮量从0增加到150 kg N·hm-2,单播中无芒雀麦的地上和地下生物量和分蘖数显著增加(P<0.05),而紫花苜蓿的地上和地下生物量和分枝数无显著变化(P>0.05)。在混播中无芒雀麦的地上和地下生物量和分蘖数也显著增加(P<0.05),在一定程度上抑制了紫花苜蓿的生物量和分枝数。另外,在混播中无芒雀麦以增加分蘖数的方式来扩张地上空间的能力要强于紫花苜蓿。无芒雀麦的单株生物量和分蘖数在混播模式下都极显著高于单播(P<0.01),而紫花苜蓿的单株生物量和分枝数在混播模式下极显著低于单播(P<0.01)。在混播中无芒雀麦的竞争率始终大于1.0,而紫花苜蓿的竞争率始终小于1.0,这说明无芒雀麦的竞争力要大于紫花苜蓿的竞争力,且在整个生育期中,无芒雀麦的竞争力逐渐减弱,而紫花苜蓿的竞争力逐渐增强。在N0处理下,第2次、第3次和第4次取样时,无芒雀麦和紫花苜蓿的相对产量总值(RYT)显著大于1.0(P<0.05),说明无芒雀麦和紫花苜蓿无明显的竞争效应,这主要归功于紫花苜蓿的生物固氮对无芒雀麦的贡献(地上部转移的氮素占无芒雀麦氮素含量的15.26[Objective] Therelationshipbetweenintraspeciific cmpetitionnandinterspecificccmpetitionsimultaneouslyexistsin mixture of legume and grass, the results of the competition led to the phenomenon that one species will be fade, the other will be a dominant gradually due to difference of the competitiveness of different plants. It is of great significance to study the mechanism of competition and coexistence between legume and grass to maintain stable and high yield in mixture grassland. [Method] A pot experiment was conducted to examine the effects of variable rates of nitrogen application （0, 75, 150 kg N＇hrn＇2）, hereafter referred asNO, N75, N150, on competition of alfalfa （Medicago sativa L.）, Smooth brome （Bromus inermis Layss.） in monocul^re, alfalfa and smooth brome in mixture （1：1）, with indicators including the relative biomass （RY）, relative density （RD）, competitive ratio （CR）, relative yield total （RYT）, percentage of atmospheric N2 fixation （%Ndfa） and percentage of N transferred （~/oN Trans）, to study the mechanism of competition and coexistence in mixcure of smooth brome and alfalfa. [Result] The results showed that with increasing of N application （from 0 to 150 kg.hm2）, the above-ground and below-ground biomass and tiller number of smooth brome significantly increased （P〈0.05）, and there was no significant difference in the above-ground and below-ground biomass and branch number of alfalfa there was no significant in monoculture （P〉 0.05）. The above-ground and below-ground biomass and tiller number of smooth brome increased, which in a certain extent inhibited biomass and branch number of alfalfa in mixture （P〈0.05）. The ability of smooth brome expand above-ground space by means of increase its tiller number was stronger than that of alfalfa in mixture. The above-ground and below-ground biomass and tiller number of individual smooth brome were significantly higher in mixture than in monoculture regardless of N application （P〈0.05�

关 键 词：无芒雀麦 紫花苜蓿 单播 混播 种内竞争 种间竞争 生物固氮 

分 类 号：S54[农业科学—作物学]