Abstract: To explore the effects of different water-potassium coupling treatments on the physiological characteristics of cold-resistant alfalfa (Medicago sativa) planted in the Horqin sandy habitat,the alfalfa varieties ‘Knight T’ and ‘Gongnong No.1’ were used as experimental materials,and two factors were used to split the random block design of the district,with water treatment as the main district:irrigation time intervals are 4 d,8 d,and 12 d respectively (indicated by W₁,W₂,W₃);The level of potassium fertilizer application was the sub-district:50 kg·hm^-2,100 kg·hm^-2 and 150 kg·hm^-2 K₂O (indicated by K₁,K₂,K₃),and set no potassium fertilizer as the control (CK). Alfalfa root crown materials were excavated in the early stage of overwintering to determine the content of MDA,SP,and antioxidant enzyme activity,and the WSR was determined in the following year. The results showed that the CAT,POD,and SOD activities,WSR,and SP content of the root crown of the alfalfa varieties of ‘Knight T’ and ‘Gongnong NO.1’ treated with irrigation time interval W₃ were significantly higher than that of the W₁ and W₂ treatments,and the value under the K₂ application rate was the most significant difference from CK (P<0.05),and the MDA content under this fertilization rate was also significantly lower than CK (P<0.05). Therefore,the production of alfalfa in the Horqin sandy land habitat with an irrigation interval of 12 d and a potassium fertilizer application rate of 100 kg·hm^-2K₂O improves the cold resistance of alfalfa.

Key words: Water-potassium coupling, Alfalfa, Overwintering rate, Antioxidant properties

摘要： 为探究不同水钾耦合处理对科尔沁沙地生境下种植苜蓿（Medicago sativa）抗寒生理特性的影响，以‘骑士T’和‘公农1号’苜蓿品种为试验材料，采用两因素裂区随机区组设计，水分处理为主区：灌水时间间隔分别为4 d，8 d和12 d（用W₁，W₂，W₃表示）；钾肥施用量水平为副区，具体施用量分别为50 kg·hm^-2 K₂O，100 kg·hm^-2 K₂O和150 kg·hm^-2K₂O（用K₁，K₂，K₃表示），并设置不施钾肥为对照（CK），于越冬前期挖取苜蓿根颈材料测定丙二醛（Malondialdehyde，MDA）、可溶性蛋白含量和抗氧化酶活性，翌年测定越冬率。结果表明：在W₃灌水时间间隔处理下，‘骑士T’和‘公农1号’品种苜蓿根颈的过氧化氢酶、过氧化物酶和超氧化物歧化酶活性、越冬率以及可溶性蛋白含量均明显高于W₁和W₂处理，其中以K₂施用量处理下的数值与CK差异最显著（P<0.05），且此施肥量下的MDA含量也显著低于CK（P<0.05）。因此在科尔沁沙地生境下生产苜蓿，灌水时间间隔为12 d、钾肥施用量在100 kg·hm^-2K₂O有利于提高苜蓿抗寒性。

关键词: 水钾耦合, 苜蓿, 越冬率, 抗氧化特性