| In order to study the change of soil salinity, soil alkalinity and main cations under long time drip irrigation with different concentration of brackish water in alluvial fan of the edge and the dry delta area in Manas River Basin, taking the representative sandy loam and clay loam soil in cotton field as the research object, using the high and low saline water for 5 years irrigation, has set up four treatments as clay loam-low salinity, clay loam-high salinity, sandy loam-low salinity and sandy loam-high salinity, measured the soil total salt, pH, Na+, K+, Ca2+, Mg2+, SAR, ESP, etc. in 0～100 cm soil layers, discussed the ions that have produced the main impact to soil salinization and alkalization, to provide the theoretical reference of ecological security for brackish water irrigation in arid area. The results indicated that: The soil salinization and alkalization in clay loam of alluvial fan of the edge and sandy loam of the dry delta area was together occurred, also was mainly affected by irrigation water salinity. The ion of main influence for soil salinization and soil alkalization was Na+ and for soil salinization was Na+ and Ca2+. It indicated that amelioration of the soil salinization in Manas River Basin should be started with reducing irrigation water Na+, and combined control of total salt content in irrigation water with reducng the proportion of Na+ to achieve the purpose of reducing salt and preventing and controlling soil alkalization. |