关键词: 银合欢, 固氮酶活性, 冻害温度, 生物量, 凋落物量

Abstract: The ecological characteristics of five varieties of Leucaena leucocephala were investigated, and the growth, above-ground biomass and litter-fall were also compared. The five varieties includsd K8, K28, K29, K67 and K132. The rasults shoved that frost-killing temperturs of each variety occared at -5℃. The optimum soil pH for their growth ranged from 5.2 to 7.5, the minimim wllting coefficient ranged from 5.1 to 5.8% in pot experiment. The nitrogenase activity of 5-year-old trees of these varieties were 34.600, 22.764, 20.840, 31.750 and 181.240 μg N₂·gFw^-1·h^-1, respectivaly, and the increment reached 2.24, 106, 1.24, 1.08 and 2.42cm per day, respectively. The above-groand biomass (dry weight) of 3-year-old forests of K8, K28,K29 and K37 were 30.53, 35.83, 30.71 and 42.80 ton·ha^-1(4444 plants/ha), respectivaly, and that of K132 was 43.56 ton·ha^-(6666 plants/ha) The annual littar-fall of five varieties stand were 4.30 4.49, 8.30, 10.7 and 12.05 ton·ha^-1, respectively.The annual biomess of the sprout land of K28 was up to 21.75-25.23 ton·ha^-1.

Key words: Leacaena leaaoaephzla, Nitrogenase activity, Frost-kit ling tetnpsrature, Blonies, Litter-fall