Abstract: By using the technology of threedimensional fluorescence spectroscopy, we studied the effects of fluorescence characteristics on water extractable organic matter in soda saline\|alkali soil (grassland, dry farmland, paddy field) under different land use patterns  in the west of Jilin Province.
 The results show that the mass ratio of organic matter in paddy field is the highest, 2708 g/kg, while the mass ratio of organic matter in grassland is the lowest, 21.63 g/kg. The mass ratio of water extractable organic matter (WEOM) is paddy field>dry farmland>grassland. The aromatic concentration is grassland>paddy field>dry farmland, and the values are 390,379,331 L/(mg·m). The fluorescence intensity of region Ⅲ and region Ⅴ is the highest in threedimensional fluorescence spectra of WEOM. The integral values of WEOM fluorescence region are humic acidlike>fulvi acid like>soluble microbial byproductlike substance>tyrosinelike protein>tryptophanlike protein. The mass ratios  of fulvic acidlike are grassland>dry farmland>paddy field,  the mass ratios of soluble microbial byproductlike substance are paddy field>dry farmland>grassland, [JP+1]and the mass ratios of humic acidlike are dry farmland>grassland>paddy field. It indicated that different land use had significant effect on the mass ratio and compos
ition of WEOM in soil.

Key words: soda salinealkali soil, water extractable organic matter, land use pattern, fluorescence characteristics