不同混播方式下豆禾混播草地种间竞争动态研究

Dynamics of Interspecific Competition of Legume-Grass Mixture under Different Mixed Sowing Patterns

以红豆草（Onobrychis viciaefolia）、紫花苜蓿（Medicago sativa）、红三叶（Trifolium pratense）、鸭茅（Dacty-lis glomerata）、无芒雀麦（Bromus inermis）和猫尾草（Phleum pratense）6种豆禾牧草在混播种类为6、5、4、3及豆禾比为5∶5、4∶6、3∶7的条件下建立混播草地,测定株高、相对密度（RD）、相对产量总和（RYT）及竞争力（CR）,比较其种间竞争的相对激烈程度及种间竞争关系动态,探讨不同混播方式豆禾混播草地稳定持续利用的可能途径。结果表明：各混播处理禾草、红三叶株高均低于单播处理,混播红豆草、紫花苜蓿则高于单播,2009年5月16日~7月1日是株高增长的快速期;各混播处理下RD1和RDg值在各测定时期均显著高于1（P〈0.05）,5月16日~6月1日期间RDl和RDg值出现了峰值,豆禾比越高则RDl值越低、RDg值越高;各混播处理下RYT值仅在5月16日显著高于1（P〈0.05）,且出现了明显的夏季低谷期;5月1日~6月16日禾草CRi值逐渐下降,豆科牧草CRj值逐渐上升,之后禾草CRi值上升,豆科牧草CRj值下降,禾草竞争力大部分时期大于豆科牧草。说明不同混播种类和混播比例组合主要通过光资源竞争改变种间竞争关系,而温度对豆禾混播牧草种间竞争关系也有明显影响。

The relative intensity of interspecific competition was investigated to reveal the approach of sustainable utilization and community stability in legume-grass mixed sowing patterns.The dynamics of interspecific relationship in four legume-grass combinations： 6 species mixture,5 species mixture,4 species mixture,3 species mixture at three rowing ratios： 5∶5,4∶6,3∶7 were studied.Stem height,relative density（RD）,relative yield total（RYT） and interspecific competition rate（CR） were measured under different legume-grass mixed sowing patterns.The results showed that the stem height of both grass and red clover（Trifolium pratense） under mixed sowing patterns was lower than that of each under singled sowing patterns.However,the forage height of both alfalfa（Medicago varia） and sainfoin（Onobrychis viciaefolia） was higher than that of each under singled sowing patterns.The forage height was increased rapidly during May 16 to July 1.Both RDl and RDg was significant higher than 1（P0.05） for all the checked points and reached the highest during May 16 to June 1.RDl decreased with increasing row ratio of legume,whereas RDg increased.RYT was significant higher than 1（P0.05） only at one check point May 16.In summer,RYT was lower than other period.Grass CRi gradually decreased during the period from May 1 to June 16,then increased after June 16.However,legume CRj gradually increased and then decreased during the same time.Grass CRi was stronger than that of legume at the most period.The interspecific competition was affected by light resources under different mixed sowing species and ratios,while temperature was another significant factor.