Effects Of Cutting Frequency On Forage Yield And Quality And Cold Tolerance Of Alfalfa Plant In Forth And Fifth

Alfalfa(Medicago sativa L.)is a forage of the worldwide largest planting-area and the widest herbage in application, which has good palatability, high protein content and general nutritive value. Alfalfa plays an irreplaceable role in the development of animal husbandry, especially improves dairy cattle yield. Cutting is the best of applying of alfalfa, cutting frequency not only affects forage yield and its quality ,but also has influence on its winter surviving rate and lasting application.In this study, ZhaoDong, LongMu801, AoHan, AErGangJin were used with 1,2,3,4 cutting frequency individually for two years. Yield, CP, CF, winter surviving rate and related physiological Indexes of cold tolerance had been determined. The results are shown as the followings.1. Hay yield was increased this year with cutting frequency increasing on the same cutting time. But the more times was cut this year.2. On the same cutting frequency of the previous year, the average content of CP of next year and total CP yield of two-year were increased with cutting frequency increasing of next year;On the same cutting frequency of the previous year, the average content of crude fiber showed a downward trend with cutting frequency increasing of next year, but the two-year total CF yield was increased.3. With cutting frequency increasing, winter surviving rates of 4 cultivars gradually reduced. By treatment of different cutting frequency, winter surviving rates of ZD and AH were significantly higher than that of AE and LM.4 With cutting frequency increasing, MDA content and relative conductivity rate in alfalfa crowns cells were obviously increased before overwintering, But activities of POD and SOD of 4 cultivars were decreased. With cutting frequency increasing, contents of soluble sugar, soluble protein, starch and praline in alfalfa were decreased.5.According to grey relevancy analysis of forage yield,quality and cold tolerance, the results of two years experiment were showed that, the best cultivar was ZD, the optimal combinations of cutting frequency (cutting frequency in 2007,cutting frequency in 2008) were 3 times,4 times; LM,AH and AE were 1 time in 2007,4 times in 2008.