Analysis And Evaluation Of Alfalfa Production Performance Under Different Growth Years And Cutting Intensity

Alfalfa has a wide range of ecological adaptability,strong ability of biological nitrogen fixation,soil improvement,soil stabilization and slope protection and vegetation restoration,high forage yield,and a variety of livestock like to eat.It is an important high quality protein forage in dairy cattle breeding and grassland animal husbandry production.In this thesis,six domestic and foreign alfalfa germplasms were selected as materials,and their biological characteristics,forage yield and relative feeding value were identified and analyzed during the five-year growth period.The purpose was to explore the dynamic changes of forage yield and quality under different growth years and different cutting intensity,and to comprehensively evaluate the production performance of the experimental materials,so as to provide references for high quality and efficient planting of alfalfa According to or for reference.The main conclusions are as follows:(1)The plant height,stem diameter and branch number of all alfalfa materials decreased with the increase of cutting times.Among them,saidi alfalfa decreased by58%in the second year,and the annual average plant decreased by 92.33cm in the fourth year;WL525 alfalfa decreased by 53%in the fourth year,and the annual average stem diameter was 3.42mm in the fifth year;The number of branches of Zhongmu No.1 alfalfa decreased by 47%after cutting three stubbles in the sixth year,and the average number of branches reached the maximum of 36.89 in the third year.(2)Compared with the first cutting,the crude protein content and ash content of all alfalfa materials increased under other cutting conditions,while the acid detergent fiber and neutral detergent fiber decreased.Among them,the crude protein content of Gannong No.9 alfalfa increased by 37%after cutting twice in the fourth year of growth,and the annual average crude protein content reached the maximum value of21.77%in the fourth year of growth;the crude ash content of saidi alfalfa increased by 19%after cutting twice in the fifth year of growth,and the annual average crude ash content reached the maximum value of 12.25%in the fourth year of growth.(3)The stem leaf ratio of all tested alfalfa materials decreased with the increase of cutting times.The stem leaf ratio of WL525 alfalfa decreased by 51%after cutting three times in the third year,and the annual average stem leaf ratio reached the minimum value of 1.03 in the fourth year.(4)The forage yield and dry fresh ratio of all alfalfa materials decreased with the increase of cutting times.The forage yield of Caoyuan No.3 alfalfa increased by5657.00kg/hm~2in the second year,and the annual average forage yield ranked in the order of Y6>Y2>Y4>Y5>Y3;the dry fresh ratio of WL525 alfalfa ranged from 2.81to 4.23,and decreased by 0.82 in the fifth year The order of dry to fresh ratio was Y2>Y5>Y3>Y4>Y6.(5)The relative feeding value of all alfalfa materials increased with the increase of cutting times,and ranked in the top 3 in the fourth year.Therefore,the relative feeding value of alfalfa was higher in the fourth year of growth,and its palatability was better.In conclusion,the best growing years and cutting times were 4 years and 3 times respectively.