Study on optimization of salt discharge parameters of farmland subsurface pipe in Bosten Lake discharge area
To explore the spatial variation characteristics of soil water and salt in the farmland of Bosten Lake drainage area and its influence on the yield of oil sunflower,the study was carried out under different subsurface pipe arrangements throughout the year,so as to optimize the appropriate local subsurface pipe salt discharge parameters and promote the management of saline-alkali land in Xinjiang,China.Taking saline-alkali farmland in Bohu County of southern Xinjiang as the research object,two kinds of buried pipes with buried depths of 1.4 m(D1)and 1.6 m(D2)and three spacings of 20(S1),30 m(S2),and 40 m(S3)were set up.The one-year irrigation period was selected and the changes of water and salt in soil profile and their effects on yield under spring flood irrigation+drip irrigation during growth period were analyzed.The overall soil salinity in the 1/2 spacing area was leached into the lower layer with water,and the soil salinity in the 0-60 cm soil layer in each treatment was significantly reduced.The static distribution of water and salt in soil profile is affected by the spacing and buried depth of underground pipes.The whole growth period of spring irrigation treatment showed that the smaller the spacing of subsurface pipes,the deeper the buried depth,the smaller the soil water content and the more uniform the water distribution,and the lower the soil salt content.The soil desalination rate of 20 m spacing was better than that of 30 m and 40 m spacing.The desalination rate of 0-60 cm soil layer reached 37.92%in the treatment of 1.6 m buried depth and 20 m of spacing in the whole growth period,which was significantly higher than that of other treatments,and the highest yield was 3 187.61 kg·hm-2.The salt discharge of the underground pipe is greatly affected by the spacing,and is less affected by the buried depth.Small spacing and deep buried pipe arrangement are conducive to salt discharge.It is suggested that the optimal buried depth and spacing are 1.4 m and 20 m,respectively,under drip irrigation in saline-alkali soil in the discharge area of Bosten Lake,which is beneficial to soil desalination and yield increase.
saline-alkali landsalt drainage by subsurface pipewater and salt distributionfull anniversary
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