紫花苜蓿与不同生活型多年生禾本科牧草混播生长生理特征

本研究通过测定紫花苜蓿分别与3种生活型禾草混播草地牧草生产力和生理指标对混播成分和比例的响应，为建植可持续高产的混播草地提供理论依据。结果显示：混播紫花苜蓿和苇状羊茅MDA含量减小，抗逆能力和光合能力增强；建植初期混播草地早熟禾MDA含量大于单播，抗逆生理和光合生理指标在豆禾比为7∶3时小于单播，5∶5和3∶7时大于单播；混播无芒雀麦MDA含量大于单播，抗氧化指标在豆禾比为7∶3时小于单播，5∶5和3∶7时大于单播，渗透调节物质含量和光合生理指标大于单播，说明紫花苜蓿与苇状羊茅混播时二者生理协同效应较好，建植初期豆禾比为7∶3时紫花苜蓿对草地早熟禾和无芒雀麦有种间竞争胁迫，适当下调紫花苜蓿比例有利于草地早熟禾和无芒雀麦生长。隶属函数评价结果显示紫花苜蓿与丛生型苇状羊茅3∶7混播时两种牧草生理表现最好，增产率和产量最高。

Physiological Characteristics of Alfalfa Mixed with Perennial Gramineous Forages with Different Life Forms

To provide theoretical basis for the construction of high yield and sustainable production of leguminosae and gramineae mixed pasture,we investigated responses of physiology and yield to mixed-sown combinations and composition ratios of alfalfa and different life-forms of perennial gramineous forage and by measuring the physiological indexes of forage and yield in artificial pastures. The results showed that:compared to monoculture,alfalfa and F arundinacea mixed sowing have higher resistance ability,and photosynthetic capacity index,lower content of MDA. At the beginning period of planting,P. pratensis of mixed-sown treatment has higher MDA content than that of monoculture. The resistance ability and photosynthetic capacity index were lower than that of monoculture at the legume-gramineae ratio of 7:3,and higher than that of monoculture at the legume-gramineae ratio of 5:5 and 3:7. The mixed B. inermis had higher MDA content,while the antioxidant enzyme activity was lower than that of monoculture at legume-gramineae ratio of 7:3 and higher than monoculture at the legume-gramineae ratio of 5:5 and 3:7. The osmotic adjustment substances content and photosynthetic capacity index were higher than that of monoculture. It showed that at thte beginning period of planting,excessive alfalfa had interspecific competitive stress on P. pratensis and B. inermis. Appropriately reducing the ratio of alfalfa could be beneficial to the growth of P. pratensis and B. inermis. According to the evaluation results of membership function,the physiology of the two forages was the best when alfalfa and F. arundinacea were mixed at 3:7. In the pasture,the two forages had the highest yield increase rate and the mixed pasture had the highest productivity.