Abstract: The potential effect of land use change on global climate change is attracting more and more attention, but in terms of estimation of terrestrial carbon budget, there have been relatively few studies on the effects of land use change on carbon balance in arid region. The large-scale change of arable land has occurred in Xinjiang, and its influences on the regional carbon balance needs to be discussed. First, we analyzed the annual arable land area change of Xinjiang based on the remote-sensing land use/cover data and the statistical arable land area data. Then, we obtained a set of local parameters for Bookkeeping model by exploring published scientific literature, soil census data and field investigation data. Finally, we analyzed the impacts of arable land change on region carbon balance of Xinjiang from 1975 to 2005 by combining mathematical statistics method and Bookkeeping model. The research shows that: land reclamation and arable land transfer were the major forms of arable land change during 1975-2005. The carbon storage of Xinjiang increased by 20.6 Tg C due to these two change forms, while land reclamation and arable land transfer led to the increments of 51.8 Tg C and -31.2 Tg C, respectively. In the period 1975-1985, owing to the large-scale arable land transfer, the changing trend of carbon storage was mainly impacted by the arable land transfer. With the increase of land reclamation scale, the changing trend of carbon storage was mainly impacted by the land reclamation after 1985. Over the past 30 years, the increase of carbon storage in Xinjiang was mainly caused by the grassland reclamation, while the transfer of arable land to grassland was the main reason for the reduction of carbon storage. Generally speaking, proceeding reasonable land and water development is beneficial to the regional carbon sequestration, and long-term management of farming activities will further enhance the carbon sink function of arable land.

Key words: LUCC, Bookkeeping model, Xinjiang, carbon balance