【摘要】 以原始阔叶红松林、次生林土壤NH+4-N与NO-3-N为研究对象,采用原位顶盖埋管法,研究2个林地土壤矿质氮供应水平与组成的差异动态。结果表明:观测期内原始阔叶红松林土壤NH+4-N含量均高于次生林,5、6、7月原始阔叶红松林土壤NO-3-N含量低于次生林,其他时段高于次生林;观测期内原始阔叶红松林土壤NH+4-N始终占优势,5、6、7月次生林土壤NO-3-N占优势,其他时段NH+4-N占优势。以红松、白桦分别作为顶级群落优势树种与退化演替群落先锋树种的代表植物,根据各器官氮含量动态与生长动态,对2个树种氮素获取行为模式进行连续研究。结果表明:红松、白桦氮吸收动态与原始阔叶红松林、次生林土壤矿质氮含量动态相似;4—10月红松持续平缓地吸收土壤氮素,5—8月白桦大量吸收土壤氮素并在6月中下旬达到吸收峰期。更多还原

【Abstract】 Soil NH+4-N and NO-3-N were the research objects,and tube closed-top incubation method was conducted to investigate the content and composition of soil mineral N in the original broadleaved Pinus koraiensis forest and the secondary forest. The results showed that soil NH+4-N content of the original broadleaved P. koraiensis forest was always more than the secondary forest from April to October,and soil NO-3-N content of original broadleaved P. koraiensis forest was less than the secondary forest from May to July. In the original broadleaved P. koraiensis forest,soil NH+4-N was always the dominating N form. In the secondary forest,soil NO-3-N was the dominating N form from May to July,and soil NH+4-N was dominated in the other months. P. koraiensis and Betula platyphylla represented respectively the dominant tree species in the climax community and the pioneer tree species in the degenerated community,whose N absorption pattern was studied continuously by investigating their organ N content and growth. The results showed that N absorption trends of the two tree species were similar to soil mineral N content trends in the original broadleaved P. koraiensis forest and the secondary forest. From April to October,soil mineral N was absorbed gently by P. koraiensis,and it was absorbed rapidly by B.platyphylla from May to August,and its peak period was late June.更多还原