General Evaluation On Study Of Yield, Qualities And Degradability About Mix-Sowing Of Alfalfa & Smooth Bromegrass

We systemic studied the yield ,quality and degradability of the pasture(alfalfaand smooth bromegrass) in different treatment plots and in different harvesting time in 2006.The material of experiment were Empor and Careton.Then,we general evaluated the value of the grassland about output character,quality character and degradability with Analytic Hierarchy Process method (AHP).So that we can give the conduction about establishing grass-legume mixture ,deciding the optimal mixture combination and the optimal harvesting time .The result showed below:Plant height Among monoculture and mixture, the plant heigh of mixture was higher than monoculture and plant heigh of treatment A (alfalfa 50% + smooth bromegrass 50% )was the highest (figure 2.1 ~ 2.6). It may be the biologic nitrogen fixation improved the fertility of soil, and smooth bromegrass can sorb the nitrogen fixation production form alfalfa.It supply the smooth bromegrass requirement of nitrogen. Effect of differnt harvesting time to plant height showed that regrowing plant heigh harvesting at legume Budding heigher than it harvested at legume early flowering, and harvest at legume early flowering'heigh higher than harvested at legume flowering'.Because harvesting early make pasture turn green and grow quickly.Yield Alfalfa was a main kind deciding the biomass of mixture . Total yield of grassland in every treatment, mixture A(1420.45kg/666.7m2) was the best one. Mixture can improved the productivity of pasture. Harvesting at flowering improved the yield of pasture in the first cutting , and early flowering improved the yield of pasture in the second cutting , third cutting an mixture d total yield.Fresh weight/ dry weight, stem/ leaf In generally, Fresh weight/ dry weight in monoculture lower than mixture. stem/ leaf was no difference in all treatment. fresh dry ratio of the forage harvested at budding was higher than early flowering, and those harvested at early flowering higher than flowering. The stem leaf ratio of the forage harvested at budding was higher than early flowering, and those harvested at flowering higher than early flowering.The quality mixture can improve significantly the crude protein content of forage and increase the ability of nitrogen fixation. The whole trend of harvesting time affecting protein content was that the crude protein content of forage harvested at early flowering was higher than budding , and budding higher than flowering.NDF and ADF content in treatment A was the highest among all treatments. Generally, HCL content of forage in Monoculture was higher than in maxture. The effect of harvesting time on NDF and ADF: NDF and ADF content of forage harvested at budding was lower than early flowering, and early flowering was lower than flowering. The HCL content in forage were inversed compared to ADF and NDF. The HCL content in forage harvested at budding was higher than early flowering, and early flowering was higher than flowering.Crude fat content of treatment B was the highest between different treatments. Crude fat content of forage harvested at early flowering was the highest between different cutting time.ASH content ASH content of alfalfa in monocluture was higher than mixture, ASH content of smooth bromegrass in mixture was higher than monocluture.In vitro degradability There was no difference in gas output that degradated in artificial rumen for 72 h between forage in monocluture and mixture. Gas output of forage in flowering was the highest.There was no difference in degradated rate of forage between monocluture and mixture. Degradated rate of forage harvested at flowering ,which was degradated in vitro in artificial rumen for 72 h , was the lowest, and early flowering was the highest one.Degradated in artificial rumen for 72 h, NH3-N concentration(average numerical value)of alfalfa in monocluture was the highest, smooth bromegrass in monocluture was the lowest, and mixture was between alfalfa and smooth bromegrass in monocluture. NH3-N concentration of degradated forage harvested at early flowering was the lowest, budding and flowering was high.general eavaluation: Result of general evaluation to every index was:treatment A (alfalfa 50% + smooth bromegrass 50%)>treatment K1 ( alfalfa 100%) >treatmentC (alfalfa 70% + smooth bromegrass 30% > treatment B (alfalfa 60% + smooth bromegrass 40%)> treatment K2(smooth bromegrass 100%), and the optimal mixture combination was treatment A. Result of general evaluation to different harvesting time: Early flowering>flowering>Budding, and the optimal harvest time was early flowering of alfalfa.