Abstract: Soil salinization and its continual improvement during the formation and development of oasis drought about the farmland drainage system landscape in downstream of oasis and area nearby desert. However, the ecological benefits of farmland drainage system evolution were unclear, which limited the comprehensive understanding about the ecological processes of artificial oasis ecosystem. In this paper, the formation, evolution, process and development pattern of farmland drainage system in recent 50 years were analyzed using the aerial photos, Landsat MSS, TM/ETM and SPOT image data in the downstream of oasis based on the graph theory, network analysis and model for landscape connectivity. Effects of the evolution of farmland drainage system on the ecological corridor, soil properties, land use change and species diversity were studied based on the buffer analysis, spatial geostatistic model, GIS correlation analysis and community diversity measurement. Furthermore, the improved biogeochemical model was used to explore the effects of farmland drainage system evolution on the regional carbon cycle and water cycle as well as the interactional mechanism between the farmland drainage systems evolution and the terrestrial ecosystem. It is of an important scientific significance for achieving the oasis agricultural sustainable development to deeply understand the effects of human activities on ecological environment in arid area and enrich the content of oasis ecology research.

Key words: farmland drainage system, ecological benefits, oasis, arid area