Effect of Simulated Acid Rain on Decomposition Rate and Dissolved Organic Carbonof Leaf Litter of Three Tree Species in Genhe

Experiments were conducted by ltter bag technique on effect of simulated acid rain on decomposition rate and content of dissolvedorganic carbon（DOC）from leaf letter of Betula platyphylla, Ledum palustre and Rhododendron dauricum treated with pH 3.5, 5.0 and 7.0 in Genhe,Inner Mongolia Autonomous Region. The results showed that leaf litter mass of 3 species reduced the less under treatment of pH 3.5, and then underpH 5.0 and pH 7.0.The mass loss rate of three species litter leaf was ordered by L.palustre＞B.platyphylla＞R.dauricum. The experiment resulted thatleaf litter decomposition rate and mass loss rate had a significant negative correlation with the content of C, lignin, C/N, lignin/N, but had remarkablepositive correlation with the content of N, P and cellulose. Decomposition and release of DOC from different litters had the same tendency, increasedfirst and then decreased, and then decreased slowly.