Abstract: The paper analyzes the effect of rotation and fertilization on alfalfa productivity on the Loess Plateau based on a long-term experiment. The result shows that the years of high alfalfa production are commonly between two to five years after its planting. The maximum production falls normally on the fifth year. Then the alfalfa yield begins to decline with each passing year. Timely fertilization could prolong its growth year. The yield also ascends or descends with the amount of precipitation.Field management should be conducted according to the growing characteristics optimizing to the reconstruction of ecology environment and agriculture activity.

Key words: Grassland science, Alfalfa, Fertilization, Yield

摘要： 在长期定位试验的基础上,分析黄土高原地区轮作与施肥对苜蓿生产力的影响。结果表明:苜蓿的高产期在2～5年,其中在第5年达到最高,尔后产草量随着生长年限的延长而逐年下降;施肥具有延长其生长年限的作用;产草量随着降水量的变化增减辐度较大,在生态环境建设和农业生产中,应根据苜蓿的生长特性采取相应的管理措施。

关键词: 草原学, 苜蓿, 施肥, 产草量