Abstract: Two alfalfa varieties(Medicago sativa L.cv.Algonquin,M.sativa L.cv.Longdong) were used for systematical investigation of Rhizobium effectiveness and analysis of influencing factors in spring,summer,and autumn in 5 ecological regions of Gansu province.The results indicate that the total nodule number and weight of Algonquin rhizobia was significantly higher than that of Longdong,but they had no remarkable difference in effective nodule number and weight.Alfalfa mainly produced nodules in spring,accounting 63.31% of total nodule number of 3 seasons,52.21% of total nodule weight,55.56% effective nodules and 51.22% of effective nodule weight.The effectiveness in spring was higher than in summer and autumn.Alfalfa rhizobia effectiveness was highest in chernozem soil,followed by irrigate soil and podzol soil;sub-meadow soil and brown soil showed weak effectiveness.

Key words: Alfalfa, Rhizobia, Noduling situation, Affecting factor, Investigation

摘要： 以阿尔冈金(Medicago sativa L. cv. Algonquin)和陇东苜蓿(M.sativa L. cv. Longdong)为材料,在甘肃省5个生态区系统调查了春、夏、秋根瘤菌(Rhizobium)有效性及其影响因子。结果表明:阿尔冈金的总根瘤数、总根瘤重极显著高于陇东苜蓿;但有效根瘤数和有效根瘤重在品种间差异不显著;两个苜蓿品种主要在春季结瘤,其总根瘤数占春、夏、秋3季的63.3%,总根瘤重占52.2%,有效根瘤数占55.6%,有效根瘤重占51.2%;春季根瘤菌的有效性比夏、秋季高;苜蓿根瘤菌的有效性以黑垆土最好,其次为灰钙土和灌淤土,而亚高山草甸土和褐土的有效性较差。

关键词: 苜蓿, 根瘤菌, 结瘤状况, 影响因子, 调查