Abstract: Soil inorganic carbon is the most common form of C in arid and semiarid climate aras，transfer of dissolved inorganic carbon in soil through the hydrologic cycle is an important component of global carbon budgets，understanding the significance of soil dissolved inorganic carbon processes can enhance development of strategies to mitigate atmospheric carbon concentrations. In order to quantity the carbon loss character in soil by field irrigation，an leaching experiment was carried out in Fukang station of desert ecology in Xinjiang. This study measured inorganic carbon leaching loses from different soil salinity （farmland soil，composite soil and native desert soil） with rice and cotton growing to explore the inorganic carbon transport mechanism with different irrigation in the saline-alkali soil of arid zone. Each kind of soil had 7 experiments with rice and cotton growing，respectively. Moreover，there were 3 controls that did not plant any crop with rice and cotton growing，respectively. The irrigation of rice was 1 100 mm，and the cotton was 470 mm. The results showed as follows：（1） The leaching inorganic carbon in the soil with rice growing mainly occurred in the period of seeding tillering and panicle development，but with cotton growing that in the period of blooming and boll opening. The amount of leaching inorganic carbon in the farmland with rice growing was maximum in the period of seeding tillering，but the amount of leaching inorganic carbon in the farmland with cotton growing was maximum in the period of blooming and boll opening. （2） The total amount of leaching inorganic carbon was higher in high salinity soil than in low salinity soil with the same irrigation. The maximum value of leaching inorganic carbon was in DR-CK （the soil control treatment of native desert soil with rice growing） treatment （approximately 8.4 g·m^-2·a^-1），but the minimum value was in FC-CK (the control treatment of farmland soil with cotton growing) treatment （approximately 0.7 g·m^-2·a^-1） in the leaching experiment. （3） The total amount of leaching inorganic carbon in the same soil type was higher in rice growing than in cotton growing. The total amount of leaching inorganic carbon in FR （farmland soil with growing rice） treatment is 2.9 g·m^-2·a^-1 higher than in FC （farmland soil with cotton growing），and value in CR （composite soil with rice growing） is 4.1 g·m^-2·a^-1 higher than in CC (composite soil with cotton growing)，and with a 3.1 g·m^-2·a^-1 higher in DR （native desert soil with rice growing） than in DC （native desert soil with cotton growing）. The total amount of leaching inorganic carbon was higher in the soil with crops growing than their corresponding control treatments（p<0.05）. These conclusions indicate that soil salinity and irrigation are the important factors to affect quantity of leaching inorganic carbon.

Key words: inorganic carbon, leaching, farmland soil, composite soil, native desert soil