中文摘要：

对取自武夷山的红壤、黄壤、黄壤性草甸土分别在对照（CK，N0mg／kg）、低氮（LN，N50mg／kg）、高氮（HN，N100mg／kg）3种氮（N）水平处理下开展培养实验，研究施加NH4^＋-N对森林土壤N转化的短期影响。结果表明，添加NH4^＋-N可显著（p〈0．05）降低土壤NO3^--N含量4．5％～25．7％，但LN与HN处理差异不显著，NO3^--N降低可能与NO3^--N反硝化和异氧还原有关；然而，黄壤性草甸土NO3^--N没有降低。与培养前比较，在第56天红壤NO3^--N含量显著增加5倍左右；桐木关黄壤增加40％左右，而黄冈山25km黄壤仅在CK处理下增加16％，但是黄壤性草甸士显著降低：结果显示LN与FIN处理土壤NO3^--N含量变化幅度小于CK。与CK相比，LN和HN处理红壤NH4^＋-N分别显著（p〈0．05）升高24．1％～96．5％和68．7％-114．1％，且随培养进行没有累积，可能与微生物固N有关；桐木关NH4^＋-N分别升高17．6％～39．6％和37．6％～95．8％（p〈0．05），LN处理黄冈山25km黄壤NH4^＋-N只有第7天升高17．8％（p〈0．05），HN处理第7、14、28、42天显著升高17．5％。48．6％（p〈0．05）。LN处理黄壤性草甸土的NH4^＋-N在前3周显著降低11．6％～28．5％（p〈0．01）；HN处理在第7天和14天分别降低10．8％（p〈0．01）和7．5％，但是在第28—56天显著增加17．6％-20．4％（p=0．002）。随着培养进行，CK处理红壤NH4^＋-N逐渐降低，桐木关黄壤、黄冈山25km黄壤和黄壤性草甸土升高：LN和HN处理黄壤和黄壤性草甸土NH4^＋-N逐渐升高。可见，不同海拔土壤类型对NH4^＋-N添加响应存在差异。

英文摘要：

The incubation experiment was carried out on soil samples of red soil, yellow soil, meadow soil of weakly-developed yellow soil from Wuyi Mountain at three nitrogen levels of the control （CK, N 0 mg/kg）, low nitrogen （LN, N 50 mg/kg）, high nitrogen （HN, N 100 mg/kg） to study a short-term effects of ammonium applied on soil nitrogen transformation. The results showed that addition of ammonium significantly （p〈0.05） decreased soil nitrate content by 4.5%-25.7% compared with CK, but no significant difference was found between HN and LN. The decrease of nitrate may be contributed to denitrification and dissimilatory reduction of nitrate to ammonium. However, ammonium addition did not decrease nitrate content in yellow meadow soil. Compared with sample analyzed before incubation, nitrate content in 56 day of incubation increased significantly by 5 times in red soil, increased by 40% in yellow soil at Tongmuguan and increased only 16% in yellow soil at Huanggangshan 25 km under CK treatment, however, soil nitrate in yellow meadow soil decreased significantly. Results showed the change magnitude of nitrate content was lower at HN and LN than CK for all soil samples. Compared with CK, ammonium nitrogen for red soil were significantly （p〈0.05） increased by 24.1%-96.5% and 68.7%-114.1% at the LN and HN treatments respectively, and no accumulation with incubation which may be related to microbial nitrogen fixation. Ammonium nitrogen of yellow soil from Tongmuguan were increased significantly by 17.6% ~ 39.6% and 37.6% ~ 95.8% （p 〈0.05） at the LN and HN, respectively. Ammonium nitrogen of yellow soil from 25 km site was increased by 17.8% （p〈0.05） only in 7 day at LN and increased by 17.5%-48.6% （p〈0.05） in 7, 14, 28, 42 day at HN compared with CK. Ammonium nitrogen in yellow meadow soil was significantly （p 〈0.01） decreased by 11.6% -28.5% compared with CK before 3 weeks at LN, it was decreased by 10.8%（p〈0.01）in 7 day and by 7.5% in 14 day, but from the 28th day to the