Abstract: Calligonum mongolicum is one of the dominant species in the Taklimakan Desert highway shelterbelt, the litter of which plays an important role in carbon cycling. After litter addition, we carried out a laboratory incubation experiment to investigate the dynamics of soil CO₂ emission, soil organic carbon (SOC), soluble organic carbon (DOC), pH, and electrical conductivity (EC) under the condition of salt water (SW) and fresh water (FW) with field water holding capacity of 25%, 50%, 75%, and 100%. The results showed that saline water irrigation had an inhibitory effect on soil CO₂ emission. Under the four soil water content treatments, the cumulative CO₂ emission of freshwater irrigation increased by 1.9%-29.1% compared with that of saline irrigation. Cumulative soil CO₂ emissions increased with increasing soil water content. With litter addition, SOC decreased rapidly in the early stage, then gradually increased, and finally tended to be stable. The DOC contents of each treatment following the incubation increased by 41.3%-92.4% compared with that before the incubation. At the end of incubation, soil pH of each treatment increased by 0.20-0.35. The EC increased with the increases of soil water content. Under the four water content conditions and compared with the situation before the incubation, the EC values irrigated with SW increased by 0.11-0.79 mS·cm^-1, while those with FW increased or decreased at the end of incubation. Cumulative soil CO₂ emission was positively correlated with SOC, DOC, and pH, but not with soil water content. Both saline irrigation and lower water content could inhibit CO₂ emission of aeolian sandy soil under litter addition, while EC was significantly affected by the quality of irrigation water and soil water content.

Key words: litter addition, soil water content, saline irrigation, CO₂ emission