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对北海道北部北海道大学雨龙试验林内的森林流域,不同景观地段的森林冠层凋落物及其养分归还量进行了为期2年的研究。湿地带分布着红皮云杉纯林,河岸带是以毛赤杨和柳树为优势树种的落叶阔叶林,而高地则分布着以白桦、大叶栎和萨哈林冷杉为优势树种的落叶阔叶与常绿针叶树混交林。湿地带、河岸带及高地森林的年平均凋落物量分别为1444、5122和4123 kg·hm-2,凋落物的高峰期出现在9-10月份,落叶量占年凋落物总量的73.4%-87.6%。除了红皮云杉和毛赤杨落叶的氮浓度无显著性季节变化外,其它优势树种落叶的养分浓度具有相似的季节变化规律。所分析的各养分元素归还量都是河岸带林分最高,而湿地带最低;各林分凋落物的不同养分归还量按其高低排序都表现出:N(11-129kg·(hm-2·a))>Ca(9-69)>K (5-20)>Mg(3-15)>P (0.4-4.7)。可见,不同景观地段的森林凋落物量及其养分归还量存在显著差异。不同景观地段的土壤化学性质有明显不同,河岸带土壤的低碳氮比可能是高质量落叶(主要是固氮树种毛赤杨)所致。
A two-year study was conducted on forest canopy litter and nutrient return in forest landscapes and landscapes in different locations in the rain forest in Hokkaido University in northern Hokkaido. The wetland is dominated by the pure spruce forest, the riparian zone is the deciduous broad-leaved forest dominated by alder and willow, and the deciduous forests dominated by white birch, Quercus variabilis and Sakhalin-fir are the highlands Broadleaf and evergreen conifer mixed forest. The annual average litterfalls of wetlands, riparian zones and highland forests were 1444,5122 and 4123 kg · hm-2, respectively. The peak of litter appeared in September-October, and the amount of deciduous leaves accounted for 73.4% of the total litterfall- 87.6%. The nutrient concentrations of deciduous leaves of other dominant species had similar seasonal variation except for the seasonal variation of nitrogen concentration in leaves of Picea koraiensis and A. chinensis. The nutrient elements returned were the highest in the riparian zone and the lowest in the wetland zone. The different nutrient returns of the litterfalls showed that N (11-129kg · (hm-2 · a))> Ca (9-69)> K (5-20)> Mg (3-15)> P (0.4-4.7). Can be seen, the amount of forest litter in different landscape sections and their return of nutrients there is a significant difference. The chemical properties of soil in different landscape areas are obviously different. The low C / N ratio of riparian zone soil may be caused by high quality deciduous (mainly Alnus).