Abstract: In order to determine the winter survival rate,grass yield and nutritional quality of different fall-dormancy-level alfalfa(Medicago sativa L.) under snow cover in winter. Fall dormancy alfalfa (grade 1,3),semi dormancy alfalfa (Grade 5) and non fall dormancy alfalfa (grade 7,9) were selected and treated with no snow and natural snowfall. The temperature changes of alfalfa canopy and 20 cm of soil depth in field were observed dynamically,and its winter survival rate,plant height,hay yield and nutritional quality were measured. The results showed that:compared with no snow cover,snow cover treatment could increase the overwintering rate of alfalfa,the plant height and hay yield of alfalfa increased under natural snowfall,and snow cover could ensure the normal production performance of alfalfa. Compared with no snow cover,snow cover only impact the crude protein content of the first crop of alfalfa in the next year,while had no significant impact on neutral detergent fiber and acid detergent fiber. According to the comprehensive evaluation of membership function,under the condition of snow cover,the fall-dormancy level 3 ‘Zhongmu 2’ and the semi-dormancy level 5 ‘Archer’ varieties performed well in overwintering rate,grass yield and nutritional quality,which is suitable for planting in Northern Xinjiang.

Key words: Alfalfa, Snow cover, Fall-dormancy level, Hay yield, Nutritional quality, Winter survival rate

摘要： 为了明确冬季田间积雪覆盖对紫花苜蓿（Medicago sativa L.）越冬率、产草量及营养品质的影响，本研究选择秋眠型（1，3级）、半秋眠型（5级）及非秋眠型（7，9级）紫花苜蓿，设置覆雪及不覆雪处理，观测紫花苜蓿根冠处及田间土层（1，20 cm）温度变化，测定其越冬率、株高、干草产量及营养品质。结果表明：与不覆雪相比，覆雪可提高紫花苜蓿的越冬率，覆雪下紫花苜蓿的株高及干草产量呈上升趋势，覆雪可保证紫花苜蓿正常生产性能。与不覆雪相比，覆雪仅影响翌年第一茬紫花苜蓿的粗蛋白含量，而对中性洗涤纤维和酸性洗涤纤维无明显影响。根据隶属函数综合评价，在有积雪覆盖的情况下，秋眠级3级的‘中苜2号’和秋眠级5级的‘Archer’品种的越冬率、草产量及营养品质表现良好，适宜在新疆北疆地区种植推广。

关键词: 紫花苜蓿, 积雪覆盖, 秋眠级, 产量, 营养品质, 越冬率