Abstract: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 56th day it was increased significantly (p = 0.002) by 17.6%-20.4% at HN. With the experiment, ammonium decreased gradually in red soil, but increased in yellow soil from Tongmuguan, yellow soil from 25 km site and yellow meadow soil at CK. However, ammonium in soil of yellow soil and yellow meadow soil was increasing gradually at LN and HN. Therefore, results indicated the response of different soil types to ammonium nitrogen addition was distinct.