In order to investigate effect of fertilization on water-soluble organic N (WSON) in the soils under chestnut stands,a fertilization experiment was carried out in Lin-an county in Zhejiang province. The results of this study showed that fertilization increased WSON in the soils under chestnut stands. Excessive chemical fertilizer addition or combined application of chemical fertilizers and organic manure had most strong effects by increasing the concentrations of WSON in the soils respectively by 5.68 and 1.94 times,compared with the unfertilized control,There was no difference in WSON concentrations in the soils among the treatments with routine chemical fertilizer rate,organic manure alone and unfertilized control. Excessive fertilizer application induced the highest ratio of WSON/total N (5.76%),which was markedly greater than that done by other three treatments. The ratio of WSON/hydrolyzed N ranged from 9.34% to 37.04% with average value of 26.78%. The highest ratio of hydrolyzed N/total N (37.04%) was found from the treatments of excessive fertilizer application and the ratio was markedly greater than that of other three treatments. The correlation analysis showed that there were significant correlations between WSON and soil total N,hydrolyzed N,water soluble total N,water soluble NH4+-N or water soluble NO3-N. The corresponding correlation coefficients were 0.565 1,0.918 6,0.998 6,0.9939 and 0.5401,respectively.
