Ultraviolet-visible Spectroscopic Characteristics of Dissolved Organic Matter Released from Forest Litterfall
森林凋落物淋溶中的溶解有机物与紫外-可见光谱特征

Laboratory leaching experiment and UV-visible spectra determination were carried out for leachates from fresh litter fall and litters in F (fragmented) and H (Humus) layers in 35-year-old plantations of Castanopsis kawakamii and China fir (Cunninghamia lanceolata) in Fujian Province. The results showed that the concentration of dissolved organic carbon (DOC) in leachate from fresh litter fall was lower and that from F layer was higher for both plantations. In Castanopsis plantation, DOC concentration declined with the increasing number of leaching times, whereas that in China fir plantation increased at first then decreased. UV-visible spectra absorption values of leachates from litter fall and different litter layers decreased with the increase of wavelength, and a peak at about 200 nm was observed in all cases. E240/E420 ratio of dissolved organic matter from different sources was quite different. The concentration of DOC in leachates from the same sample was linearly correlated with E200 (R2>0.90), suggesting that DOC concentration could be estimated at E200.