Experimental Study On The Effect Of Salt Control On Saline Meadow Soil Covering Measures

The Horqin area has a continental arid and semi-arid climate,and saline-alkali land accounts for 50.6%of the cultivated land area in the area.The unreasonable development and utilization of humans have caused salinization of the soil,restricting the agricultural development and livelihood of the area.In this study,the salinized sandy meadow soil in Horqin area was taken as the research object.Through field soil column experiments,sand-covered 20 cm+humic acid(T1),sand-covered 30 cm+humic acid(T2),sand-covered 40 cm+humic acid(T3)5 sand-covered 80 cm(T4)and undisturbed saline-alkaline soil(CK)five ways to explore the law of water and salt movement under different sand cover measures,and to explore the salt control effects of different sand cover measures and their effects on improving soil nutrient status and promoting grass growth.The results are as follows:(1)The height of capillary water in this texture sandy soil is 53cm,and a dry sand layer is formed above this height.(2)It was found that during the period from the beginning of the experiment to 24 hours,the moisture increased rapidly and formed obvious wet marks,delamination phenomenon in the soil column also appeared,and then the soil column moisture remained constant for a long time after that.(3)When the burial depth of the phreatic water is greater than the rising height of the capillary water,showing a trend of gradually accumulating at the capillary fracture point with the passage of time.When the burial depth of phreatic water is less than the rising height of capillary water,the movement of water and salt shows the same trend.(4)The soil pH value T4 treatment is the lowest;the order of contribution rate of each teatment to reducing salt content was T4>T1>T2>T3>CK.the soil alkalinity of T4 treatment was the lowest,followed by T1 treatment;the content of Na+and K+in the treatment of T1,T2,T3 and T4 was between 1.06cmol/kg to 1.39cmol/kg and decreased by 1.68cmol/kg to 2.01cmol/kg compared with that of CK;the content of HCO3-was the lowest in T4 treatment.(5)The soil organic matter content T1 treatment was significantly higher than T4 and CK;the order of total nitrogen content is T1>T2>T3>CK>T4;the content of available phosphorus in T1,T2 and T3 treatments increased by 9.7%to 20%compared with CK,and available potassium increased by 21%to 27%;the content of alkali-decomposed nitrogen in T1 treatment was significantly higher than that in T4 and CK.(6)The plant height and dry weight of Elymus dahurica,alfalfa,and clover under T2 treatment were all greater than those of the other two treatments.Among them,the plant height of Elymus dahurica T2 treatment was significantly higher than that of T1 treatment,and the dry weight T2 treatment was significantly higher than that of T3 treatment;the root dry weight and root length of T2 were also higher than those of T1 and T3,but there was no significant difference among the three treatments.Combined with the aboveground biomass and underground biomass with different sand cover thickness,the forage growth of T2 treatment was the best,followed by T1 treatment.