关键词: 紫花苜蓿, 生产性能, 不同茬次, 年际间, 动态变化

Abstract:

In order to illustrate the dynamic change of the production performance of alfalfa between cutting times and years, two experiments for seven years (22 varieties) and four years (14 varieties) were conducted in the Hai River Plain. The results indicated that the average dry matter yields decreased with the cutting times increasing; the dynamic of dry matter yields for 4 times one year was:1^st cutting > 2^nd and 3^rd cutting > 4^th cutting, the dynamic of dry matter yields for 5 times one year was:1^st cutting > 2^nd cutting > 4^th cutting > 3^rd cutting > 5^th cutting. The average dry matter yields of the 1^st and 2^nd cutting accounted for over 52% of the whole year, and the yields of 3^rd cutting could only account for less than 25%. The average plant height (both 22 varieties and 14 varieties) declined with the cutting times increasing. The average Leaf-Stem ratio (both 22 and 14 varieties) of the 2^nd cutting was significantly higher than the 3^rd and 4^th cutting (P<0.01), the 4^th cutting was the lowest. The average crude protein content (both 22 and 14 varieties) of the 2^nd and 3^rd cutting were higher than the 3^rd and 4^th cutting, and the differences were significant (P<0.01). There were obviously "summer slump" phenomena which could cause the waste of light, temperature and water resources. The seven years continuous test showed that the yields decreased from the fifth years, therefore the suitable utilized years were 4~5 year in the Hai River Plain.

Key words: Alfalfa, Production performance, Different cutting times, Interannual, Dynamic change