Abstract:Soil organic matter (SOM) accumulates rapidly in the Phyllostachy spraecox. Preveynalis soil due to its special intensive management. Enriched soil Al may exert a great effect on SOM decomposition. In this paper, an in-vitro incubation experiment was conducted to investigate the influence of amorphous aluminum hydroxide (AAH) additions (0, 2, 10, 20 and 40 g/kg respectively) on SOM of Phyllostachy spraecox. Preveynalis. Results showed that the addition of AAH significantly inhibited SOM decomposition. The inhibition rates were 56.97%, 60.75%, 58.87% and 44.25% respectively on the soils with 0, 1, 5, 15 planting years when 40 g/kg Al addition, while the inhibition rates on the control soil (paddy soil) were 7.49%, 38.04%, 50.79% and 56.98% respectively when Al addition rate were 0, 2, 10, 20, and 40 g/kg. Overall, the inhibition rate on SOM decomposition increased with increasing Al addition amount but decreased with increasing SOM content.