The Study On Adaptability Of Alfalfa In The Purple Soil Of Changjiang Gorges Reservor

Under the natural condition, five alfalfa varieties of Canada Algonguin,Defi,Derby,Sanditi and Eureka from aboard and Wuxi Red clover from domestic and 'Ladino' white clover were identified on analysis of characteristics and adaptability through 4 years( 1999-2002) in median altitude area( 550m) of Changjian Gorges Reservoir. The results of variance analysis showed :1. phenophase result shows that the regreen stage of treatment cultivars is between Mar.7 and Mar. 15, and sandity gets green earliest, Derby and Deft do later. Branching stage is between Apr. 5 and Apr. 10, the difference of cultivars is not significant. Derby's Earn flowering stage is the earliest, other cultivars is later 2 to 5 days.2. Algonguin, Eureka and Derby had the characteristics of good adaptability,high yield,strong regeneration,high ecological and economic value and so on,which was favorable in planting on large areas.The hay yield (16558kg, 16730 kg, 17126 kg) of three alfalfa varieties is higher 28%,29.7% and 32.8% than Wuxi Red clover and higher 24.5%,25.8% and 28.8% than 'Ladino' white clover .In the beginning of bloom, the coarse protein of three alfalfa varieties is higher 1.2%,0.8% and 0.6%,and higher 1.0%,0.6% and 0.4% than 'Ladino' white clover.3. The undergroud biomass of alfalfa shows that biomass decreases from top layer to bottom layer, the biomass from surface to undergroud 50cm is 81.5% of total biomass, and is 15.2% from undergroud 50-100cm, and is 3.3% below 100cm. Algonguin root system is the deepest(l.5m), its root extent is the smallest; Sandity alfalfa root system is the shortest, its root extent is the bigest. The toot characteristics of other alfalfa cultivars is similar.4. Few alfalfa cultivars from aboard have strong drought-resistance ,heat-resistance, disease-resistance , which adapts to climate conditions of Three Gorges Reservior. In the same time, alfalfa's root system is strong, and have strong soil preservation ability and high ecological efficiency. In addition, through nitrogen fixation of root nodule bacteria, the soil fertilization increases.5. Based on analysis of alfalfa's general character, the eco-adaptation,hay yield,forage quality,regeneration of Derby,Algonguin and Eureka are superior to domestic cultivar "Wuxi" red clover and main planting forage "Ladino" white clover,which is favorable in planting on large areas.