Cultivation Techniques Of Alfalfa On The Loess Plateau

The cultivation techniques of alfalfa on the Loess Plateau,including seed vigor evaluation,rhizobium inoculation,seeding rate and fertilization were studied,and the main results were as following:1.To select the best method estimating seed vigor of alfalfa,the standard germination test,cold germination test,just germination test and electrical conductivity test were conducted to evaluate seed vigor of 10 seed lots of alfalfa,the results showed that cold germination test,just germination test and electrical conductivity test performed better in distinguishing seed vigour among 10 seed lots.Electrical conductivity test was the most sensitive method for M.sativa seed vigor evaluation,and identified 7 levels for 10 seed lots in terms of EC values;followed by cold germination test and just germination test which identified 6 levels for 10 seed lots;while standard germination test identified 10 seed lots as 3 levels only.2.Inoculation with 17767 strains increased seedling biomass,plant height,number of branches and number of leaves of M.sativa cv.Gannong No.3 by 102%,100%,17% and 102%,respectively,in the greenhouse,while inoculation with 17625 strains increased seedling biomass,plant height,number of branches and number of leaves of M.sativa cv.Longdong by 187%,48%,80% and 47%,respectively.In the field condition,seedling biomass and plant height of M.sativa cv.Gannong No.3 was increased by 21% and 13%,respectively after inoculation with 17650 strains;while Longdong cultivar inoculated 17574 strains increased seedling biomass and plant height by 348% and 70%,respectively.Inoculation with 6-3,17537,129,17670,17582,17578 and 17650 strains treatments increased plant water use efficiency to some extent in Longdong cultivar.Based on their performance both in the greenhouse and field condition,the optimal symbiotic rhizobial strains with M.sativa cv.Gannong No.3 and M.sativa cv.Longdong was B2 and 17650,respectively.3.By comparing different seeding rate and row space on alfalfa hay yield and quality,the seeding rate of 22.5 kg/ha,with row spacing of 40 cm and the seeding rate of 22.5 kg/ha,with row spacing of 20 + 40 cm,hay yield was the highest;seeding rateof 15.0 kg/ha,with row spacing of 40 cm,its nutrient composition and relative forage value was the highest.4.The effects of different nitrogen,phosphorus and potassium fertilization rate on hay yield and quality of alfalfa in the field were determined,and the results showed that: 1)the highest yield was exhibited which was 18000 kg/ha when nitrogen fertilizer was 100 kg/ha,phosphate fertilizer was 120 kg/ha and potassium fertilizer was 180 kg/ha;2)the crude protein was up to 20% when nitrogen fertilizer was 100kg/ha,phosphate fertilizer was 120 kg/ha and potassic fertilizer was 0 kg/ha.