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

摘要： 五个银合欢品种K8、K28、K29、K67和K132的盆栽苗经人工气候箱冻害试验表明,-3℃时各品种未发生冻害现象,至-4℃时叶片冻萎而脱落,转入常温下茎梢可以恢复生长;-5℃时茎,根全冻死,皮层坏死。K28萎蔫系数,沙壤土为5.1%~5.3%,粘红壤土为5.6%~5.8%。pH值最适范围5.2~7.5,pH<5.0或>8.0时生长受阻。5年生各品种根瘤固氮酶活性分别为34.600、22.764、20.840、31.750和121.240 μgN₂·gFw^-1·h^-1。生长季高度生长量分别为2.24、1.06、1.24、1.08和2.42 cm·d^-1,年平均生长量(高/朐径)分另11为2.0/1.4、1.9/1.3、1.6/1.4、1.6/1.4和1.9/1.2 m·cm^-1。3年生人工林地上邯生物量分别达30.53、35.86、30.71、42.80和43.66 t·ha^-1,凋落物量分别为4.30、4.49、8.30、10.87和12.05 t·ha^-1·a^-1。K28萌蘖条1年生物量达21.75 t·ha^-1(丘陵旱地)和25.23 t·ha^-1(池边湿地)。

关键词: 银合欢, 固氮酶活性, 冻害温度, 生物量, 凋落物量