模拟氮沉降对中亚热带森林土壤Ni、Cu、Zn含量的影响

通过野外模拟实验,研究3个氮沉降水平,CK(对照,0 kg·hm^-2·a^-1)、LN(低氮,30 kg·hm^-2·a^-1)和HN(高氮,100 kg·hm^-2·a^-1)处理对亚热带针叶(杉木)和阔叶(罗浮栲、浙江桂)森林土壤中微量元素Ni、Cu、Zn含量的影响。结果表明:就不同的林分来看,3种微量元素的含量大致呈杉木林>罗浮栲林>浙江桂林,施氮3 d后,浙江桂林和罗浮栲林土壤中3种微量元素在各处理之间差异不显著,仅发现杉木林土壤中的Ni含量在CK处理与LN及HN处理之间和无凋落物土壤中Cu含量在HN与CK及LN之间的差异显著; 3片林分中土壤表面有无凋落物处理总体对3种微量元素含量的影响不大。与施氮前相比,3片林分土壤中的Ni、Cu、Zn含量均有所下降,且浙江桂林在LN处理的降幅最大。

Effects of simulated nitrogen deposition on Ni, Cu and Zn in subtropical forest soils

A field-simulated nitrogen deposition experiment was conducted to investigate the effects of added nitrogen on soil the microelements Ni,Cu and Zn in two adjacent natural broad-leaved forests(Castanopsis fabric,CAF and Cinnamomum chekiangense,CIC)and a coniferous plantation(Cunninghamia lanceolata,CUL). Three treatments were set as the control(CK)of 0 kg·hm^-2·a^-1,low nitrogen(LN)treatment of 30 kg·hm^-2·a^-1 and high nitrogen(HN)treatment of 100 kg·hm^-2·a^-1. The results showed that the orders of three kinds of microelements content were roughly CUL>CAF>CIC. After three days of nitrogen addition,significant effects were only found between CK and LN or HN for Ni content in the CUL forest soil and between HN and CK or LN for Cu content under litter removed,and there were no significant differences among all treatments in CIC and CAF forest soil. On the whole,the impact of litter for three kinds of forest soils on microelements content was not found. Compared with the data before nitrogen addition,Ni,Cu and Zn contents in the three forest soils all decreased,with the most decreasing amplitude for CIC forest soil at the LN treatment.