关键词: 科尔沁沙地, 叶凋落物, 沙漠化, CO₂释放

Abstract: CO₂ releases of the decomposed leaf litters of 30 species in Horqin Sand Land were measured with incubation method. The results showed that: ①The amount of CO₂ released from the decomposed leaf litters in the period of 28 day incubation was greatly different. The averaged CO₂ released amount of perennial leaf litters was greater than that of the annuals, but not significant, while the averaged CO₂ released amount of Gramineae was less than that of the other plants and significantly different. ②The rate of CO₂ released every four days was significantly different. The CO₂ release rate of Gramineae leaf litters was significantly different from that of the other plants in the first 16 days, and then the significance decreased, while the CO₂ release rate of the annual leaf litters was not significantly different from that of the perennials. ③The difference in C, N, C/N, Ash/N and Ash content of leaf litter was the major cause of the difference of CO₂ release amount and rate. CO₂ release amount of leaf litter was not significantly correlated to the initial carbon content and ash content of leaf litter in the 28 days, but positively correlated to the initial nitrogen content and negatively correlated to C／N and ash/N of leaf litters. CO₂ release rate of leaf litter was no correlation to the initial carbon content of leaf litters, if calculated every four days, but strongly and positively correlated to the initial content of nitrogen and strongly and negatively to C／N of leaf litters in the period of 0 to 20 days; CO₂ release rate was strongly and negatively correlated to the ash/N of leaf litters in the period of 9th to 28th day, and correlated negatively to ash content in the period from 17th to 28th.

Key words: Horqin Sand Land, leaf litter, desertification, CO₂ release