中文摘要：

采用室内培养试验,研究了不同凋落物和单宁酸对森林土壤硝态氮和铵态氮的影响.结果表明：凋落物和单宁酸加入均降低了土壤硝态氮和铵态氮含量.杉木凋落物使红壤硝态氮和铵态氮含量分别降低6.1%～25.9%和19.7%～68.6%.杉木凋落物中黄红壤无机氮含量的降幅大于毛竹,对铵态氮的影响极显著.与对照相比,单宁酸处理能显著降低黄红壤中铵态氮含量,单宁酸浓度越高,其降幅越大,至高浓度（HG）时,其降幅达31.9%～57.8%.随着培养时间的延长,低浓度单宁酸处理（HL）中硝态氮含量降幅逐渐增大,第84天达到4.5%;在HG处理下,第7～28天的硝态氮含量增加了10.3%～18.5%,而第56和85天分别降低23.9%和42.3%.

英文摘要：

A laboratory incubation test was conducted to study the effects of litters and tannin on forest soil nitrate-and ammonium N. The addition of litters and tannic acid made the soil nitrate-and ammonium N decreased. With the addition of fir litter,the nitrate-and ammonium N contents in red soil decreased by 6.1%-25.9% and 19.7%-68.6%,respectively,and the decrements in yellow-red soil were higher than those with the addition of bamboo litter,being significant for ammonium N. Compared with the control,the addition of tannin decreased the ammonium N content in yellow-red soil significantly,and there was a positive correlation between the concentration of added tannin and the decrement of soil ammonium N content. When the concentration of added tannin was high,the decrement of the ammonium N reached 31.9%-57.8%. With the addition of low concentration tannin,the soil nitrate N content decreased with time,and the decrement on the 84th day reached 4.5%. However,the addition of high concentration tannin increased the soil nitrate N content by 10.3%-18.5% in the first 7-28 days,but decreased it by 23.9% and 42.3% on the 56th and 85th day,respectively.