In order to explore the law of soil salinity and ion migration and aggregation under different irrigation and drainage modes in salinized irrigated area

From May to October 2021

soil water and salt monitoring and irrigation and drainage water monitoring were carried out in farmland under the modes of "drip irrigation+open ditch drainage" and "flood irrigation+dark pipe drainage" in the saline-alkali cultivated land improvement demonstration area in Wuyuan County

Bayannaoer City.To analyzed the migration and distribution of soil salt under different irrigation and drainage modes

and to explore the characteristics of soil salt and salt ion accumulation and desalting by equilibrium analysis

so as to provide scientific basis for water-saving planning and salinization prevention and control in irrigated areas.The results showed that the farmland soil was in a state of desalination under different irrigation and drainage modes

and the soil desalting effect was relatively good under "flood irrigation+dark pipe drainage" mode

the desalting rate is 37.73%.HCO3- was in a state of accumulation under "drip irrigation+open ditch drainage" mode

and the accumulation was 0.3 t.The accumulation of Ca2+ and Mg2+ occurred under "flood irrigation+dark pipe drainage" mode

the accumulated amount is 2.962 4 t and 0.577 4 t

respectively.During the whole growth period under "drip irrigation+open ditch drainage" mode

the 0—40 cm soil layer was in a state of desalinization

and the 40—80 cm soil layer appeared salt accumulation.Under "flood irrigation+dark pipe drainage" mode

the 0—100 cm soil layer was in desalinization during the entire growth period.The groundwater depth was the same under different irrigation and drainage modes.The groundwater depth was lower under "flood irrigation+dark pipe drainage" mode.The soil salt accumulation and groundwater quality were negatively correlated under "drip irrigation+open ditch drainage" mode

only HCO3- in soil was positively correlated with each ion of groundwater

and HCO3- in soil was strongly correlated with Mg2+ and HCO3- in groundwater

and the correlation coefficients were 0.833

0.759

respectvely.The overall correlation between soil salinity and groundwater quality was not obvious under "flood irrigation+dark pipe drainage" mode.