三江平原露水资源研究

研究了三江平原露日的变化特征,并对沼泽地毛果苔草(Carexlasiocarpa)群落和大豆地中露水的凝结进行了实地观测。结果表明:三江平原露水出现频率较高的季节是夏秋季(6～9月),露水凝结量最多的月份是9月;近12年来,年露日在66～108d,平均为95.42d;7～9月大豆地地面的露水凝结量明显高于沼泽地地面,而5～6、10月低于沼泽地地面;沼泽地中冠层的露水凝结量最多,地面上的露水量略低于顶层,而大豆地中露水凝结量的垂直差异不明显;2003年沼泽地、大豆地单位土地面积上实际凝结的露水量为20.68、19.46mm,分别占同期降雨量的5.05%、4.75%。露水在一定程度上弥补了干季降雨的不足,是影响水量平衡的重要因子。

Study on the Dew Resource in the Sanjiang Plain

Change characteristic of dew days in Sanjiang Plain was studied and dew was in situ collected using the collectors of poplar sticks in soybean field and marsh land from May to Oct. 2003.Carex lasiocarpa is the dominant plant in marsh land.At the same time, temporal and spatial changes of dew content were analyzed,including seasonal change and vertical distribution between marsh land and farmland.Dewfall condenses mainly in summer and fall and the peak of dewfall appears in September.The number of dew days in the years of 1992～2003 ranged from 66 to 108,and the mean is 95.42.The dewfalls in July,August and September collected on the surface of soybean field were higher than those on that of marsh land,and the dewfalls in May,June and October were lower than those of marsh land.The dewfalls varied with the height and dewfall was the richest in canopy in marsh land,and vertical changes of dewfalls in soybean field were unconspicuous.The unit area actual dewfalls in marsh land and soybean field reached 20.68mm and 19.46mm in 2003,which accounted for 5.05% and 4.75% of the rainfalls of the same period,respectively.Dew plays an important role in keeping water balance of marsh ecosystem and farmland ecosystem,and may compensate the shortage of rainfall in growth season of crops.