模拟N沉降对杉木人工林枯落物养分的影响

通过野外模拟实验,研究了8年后N沉降(4种处理分别为N0(0)、N1(60)、N2(120)和N3(240 kg·hm-2·a-1)对杉木(Cunninghamia lanceolata)人工林枯落物养分的影响.结果表明,未分解叶中,N沉降增加了N、Zn、Fe、Mn的含量;低N处理促进了Ca和Mg的含量,而中高N抑制了Ca和Mg的含量.未分解层枝中,N沉降增加了N和Mn的含量,降低了K、Ca、Mg、Zn的含量.N1、N2和N3处理提高了枯落物未分解层叶中养分元素的现存量;随N沉降量增加,未分解枝中N、P、Fe和Mn的贮量,K、Ca、Mg和Zn呈现先增加后减少的趋势;在半分解层,Fe元素贮量随N沉降量的增加而逐渐递增.

Effects of Nitrogen deposition on litter nutrient in Chinese fir plantations

Through field experiment, this paper studies the response of the litter nutrient to N deposition （Treatment of N was designed as 0,60,120,240 kg . hm^-2. a^-1） in the Chinese fir （Cunninghamia lanceolata） plantations after eight-year use of N fertilizer. The results show that, N treatment increases an average content of N, and reduces that of K, Ca and Mg. In the L layer, all N treatments settlement increa- ses the contents of N and trace elements Zn, Fe, Mn of leaves ;low N treatment enhances the content of Ca and Mg,while a high N has an adverse effect. For the branches,N treatment raises the contents of N and Mn and decreases that of K, Ca, Mg,Zn elements ;N1 ,N2 and N3 lead to a rise in the accumulation of the eight nutrient elements in leaves in the L layer. Meanwhile, the storage of N, P, Fe and Mn of the branch increases along with the N deposition, whereas K, Ca, Mg and Zn decreases from NO to N2 but increases in the level of N3. In the F layer,only the amount of Fe elements shows a gradual climb as the N settlement goes up.