中文摘要：

以黄土高原区8种植物凋落物为对象,利用水和0.01mol·L-1CaCl2两种浸提剂提取了不同大小（2mm和1cm长）的凋落物,测定其可溶性有机碳含量,并利用室内培养试验评价其生物降解特性.结果表明：不同植物凋落物可溶性有机碳含量在18.20～156.82g·kg-1,占其全碳比例的4.21%～32.84%.其中,灌木凋落物可溶性有机物含量及其占全碳的比例略高于乔木,草本最低.经过7d的培养,不同凋落物可溶性有机碳的生物降解率在44.5%～80.6%,平均为62.9%;不同种类凋落物的生物降解率为灌木〉乔木〉草本.培养结束后,溶液中结构较复杂的可溶性有机物比例呈显著上升趋势,与其中易降解组分的降解有关.说明可溶性有机碳在黄土高原区退耕还林还草过程中的物质循环及能量转化方面具有重要作用.

英文摘要：

The litters of eight plant species from the Loess Plateau were cut into pieces with 2 mm and 1 cm in size,and extracted with distilled water and 0. 01 mol·L -1 CaCl2 to determine the soluble organic carbon （ SOC） content. In the meantime,a 7-day indoor incubation test was conducted at （ 25 ± 3） ℃ to investigate their biodegradability. The SOC content and the ratio of SOC to to- tal carbon （ SOC/TC） in the litters were 18. 20 - 156. 82 g·kg -1 and 4. 21% - 32. 84% ,respectively. Shrub litter had a slightly higher SOC content than tree litter,while grass litter had the lowest SOC content. After 7-day incubation,the biodegradation rate of SOC in the plant litters ranged from 44. 5% to 80. 6% （ 62. 9% on average） ,and decreased in the order of shrub tree grass. By the end of the incubation,the proportion of soluble organic matter in solution had a significant increasing trend,which was related to the rapid biodegradation of labile composition in the litters. The higher content and higher biodegradation rate of SOC in plant litters might play important roles in nutrient cycling and energy flow during the vegetation restoration on Loess Plateau.