Abstract: Different nitrogen (N),Phosphorus (P),potassium (Potassium,K) fertilization combinations and mixed sowing ratios of grasses were used to study the effects of the nutrition contents and ecological stoichiometric characteristics on grass with alfalfa (Medicago sativa) + smooth brome (Bromus inermis) grassland. The results showed that effects of fertilization on the first cutting N,P,K contents and C:P rate,the second cutting P,K contents and C:P,N:P rate,and the third cutting C,P,K contents,C:N,C:P,N:P rate in grass were extremely significant (P<0.01). The C,P,K contents and C:P,N:P rate of the first,the second and the third cutting N,P,K contents and C:P,C:N,N:P in alfalfa were effected extremely significantly by fertilization (P<0.01). The P content and C:P of the first cutting and C content of the second cutting and C:N,N:P of the third cuing in grass was affected extremely significantly by legume-grass mixed sowing ratios (P<0.01).The interaction of fertilization and mixed sowing ratio had a very significant effect on the C content of each cutting and the first,second cutting P content and C:P rate in grass and the P content and C:P rate of each cutting and the first and second cutting N:P in alfalfa. The N:P rate of grasses ranged from 3.53 to 7.60 and the alfalfa ranged from 8.37 to 12.32. It was indicated that the growth of grass was mainly affected by nitrogen,while the growth of alfalfa is affected by both nitrogen and phosphorus.

Key words: Fertilization, Mixed sowing ratio, Alfalfa, Smooth brome, C,N,P and K content, Ecological stoichiometric ratio

摘要： 本研究以紫花苜蓿（Medicago sativa）与无芒雀麦（Bromus inermis）混播草地为对象，研究了施用不同比例氮（Nitrogen，N）磷（Phosphorus，P）钾（Potassium，K）肥与不同混播比例对牧草营养元素含量及生态化学计量特征的影响。结果表明：施肥对1~3茬无芒雀麦P，K含量、C （碳，Carbon）：P和K：P以及1茬N含量、2茬N：P、3茬C含量和C：N，N：P影响极显著（P<0.01），对1茬和2茬苜蓿C，P，K含量和C：P，N：P以及3茬N，P，K含量和C：P，C：N，N：P，K：P影响极显著（P<0.01）；混播比例对1茬无芒雀麦P含量和C：P，2茬C含量和3茬C：N，N：P影响极显著（P<0.01）；施肥与混播比例互作对1~3茬无芒雀麦C含量、苜蓿P含量和C：P，1茬与2茬无芒雀麦P含量和C：P以及苜蓿N：P影响极显著（P<0.01）。禾草N：P在3.53~7.60之间，苜蓿在8.37~12.32之间，表明无芒雀麦生长主要受N素影响，苜蓿生长同时受N素和P素的影响。

关键词: 施肥, 混播比例, 苜蓿, 无芒雀麦, 碳氮磷钾含量, 生态化学计量比