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水冬瓜树因其树皮灰色象冬瓜皮,又喜生于湿地、水边而得名。系桦木科桤木属,学名叫江南桤木(Alnus trabeculosa, Hand-Mazz),为落叶乔木,高达10—15米,是速生用材树种。分布于江苏、浙江、四川等省,我省淮河以南大部分县均有零星生长,垂直分布在大别山区高达海拔千米左右。我省霍邱县南部农田、村庄、池塘四周和河流两岸生长甚多。据观测,水冬瓜树冠小,而且通风透光性能好;根有根瘤菌,能固定空气中的氮;叶子含氮量高,每100斤干叶含氮量2.9斤(相当于18斤尿素含氮量)、磷0.4斤、钾1.1斤。据四川省盐亭县试验,每亩水田施鲜叶500斤,水稻增产19％左右,施鲜叶800—1,000斤可增产25％左右。是农田林网化的优良树种。
Water melon tree because of its gray bark of winter melon skin, but also born in the wetlands, waterfront named. Department of birch Branch Alnus, scientific name is Alnus trabeculosa (Alnus trabeculosa, Hand-Mazz), deciduous trees, up to 10-15 meters, is a fast-growing timber species. Distributed in Jiangsu, Zhejiang, Sichuan and other provinces, most of the county south of the Huaihe River have sporadic growth, vertical distribution in the Dabie Mountains up to about 1000 meters above sea level. Huoqiu County, southern farmland, villages, ponds and rivers around the growth of many. It is observed that the water melon canopy is small, and good ventilation and light performance; root rhizobia, can fix the nitrogen in the air; leaves high nitrogen content per kilogram of dry leaves nitrogen content of 2.9 kg (equivalent to 18 kg urea containing Nitrogen), phosphorus 0.4 kg, potassium 1.1 kg. According to the experiment of Yanting County in Sichuan Province, 500 kilograms of fresh leaves per mu of paddy field were applied, about 19% of rice yield was increased, and 800-1,000 kilograms of fresh leaves were applied to increase yield by 25%. Is an excellent farmland network of trees.