Study on the Characteristics of Salt Migration in Sandy Soil Under Saline Groundwater Drip Irrigation in Shelter Forest Area along the Golmud-Korla Railway
Haloxylon ammodendron is an important desert plant in maintaining ecological balance in desert regions.In the area where salt water is abundant but fresh water is insufficient,it is of great significance to study the distribution and accumulation of salt in soil profile by using salt water to irrigate ammodendron.This study adopted the method of combining outdoor soil column simulation experiment with indoor analysis,and adopted the water irrigation treatment with five salinity levels of fresh water(CK),20 g/L、30 g/L、40 g/L、50 g/L.The experimental results showed that:① High salinity water drip irrigation has a significant impact on soil salt content and ion composition.In general,the degree of soil salt accumulation increases with the increase of salinity of irrigation water.In the vertical direction,the salt content of the surface salt crust soil is much higher than that of the subsoil,and the salt content of the subsoil on the whole increases with the deepening of the soil layer,while the soil pH value,on the contrary,tends to decrease with the deepening of the soil layer,and the soil gradually changes from non-saline soil to mildly saline soil.② Soil salinity is mainly composed of Cl-and Na+,and contains more SO42-ions.The content of Cl-,Na+,Ca2+,K+,Mg2+ and SO42-six ions from topsoil to bottom experienced a sudden drop.Then,as the soil layer deepened,the content of ions increased to different degrees,presenting surface accumulation and deep accumulation characteristics.CO32-and HCO3-presented surface accumulation characteristics.③ When the salinity of irrigation water is between 20～30 g/L,ammodendron can still grow well,but more than 30 g/L,although ammodendron can survive,its growth is obviously inhibited.This study has theoretical significance and application value for rational exploitation and utilization of high salinity groundwater in arid areas and construction of shelterbelt in desert areas.
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