Effects Of Different Improved Materials On Water And Salt Characteristics Of Coastal Clayey Saline Soil

Coastal saline-alkaline soil is an important land reserve resource,but it faces problems such as low soil saturated hydraulic conductivity,difficulty in salt leaching,and shortage of fresh water resources.How to solve the problem of soil salinization scientifically and effectively is an urgent need to solve in coastal areas.Important topics.This study selects yellow water diversion sand,active potassium humate,and desulfurized gypsum as the improvement materials,combined with the comparison of salt water supplementary irrigation and ordinary fresh water irrigation,through the measurement test of saturated hydraulic conductivity of the simulated soil column,and the simulated soil column salt leaching test Comparing and analyzing the effects of three improved materials on soil saturated hydraulic conductivity,soil water and salt content and wheat yield with field experiments.The main research conclusions are as follows:(1)The combined application of yellow sediment and desulfurized gypsum can significantly increase the saturated hydraulic conductivity of the soil.When the combined application rate of yellow water diversion sediment is 33.33%-50%,and the combined application rate of desulfurization gypsum is 0-1.4%and 2.2%-3.2%,the saturated hydraulic conductivity of the soil increases significantly with the increase of the modified material application rate.The combined application rate of active potassium humate has a linear negative correlation with the saturated hydraulic conductivity of clay soil,and has little effect on increasing the saturated hydraulic conductivity of the soil.(2)There is a significant negative correlation between the salinity of clayey saline soil and the amount of sediment diversion from the Yellow River.When the maximum combined application rate of sediment from the Yellow River was 50.33%,the salt content of the soil was reduced by 47.78%and 53.16%compared with CK treatment after saline and fresh water irrigation.After salt water irrigation,the salt content of the soil treated with potassium humate increased first and then decreased.The soil salt content of each treatment was higher than that of CK;after fresh water irrigation,when the potassium humate dosage was greater than 0.16%At time,the salt content of the soil showed a decreasing trend.After salt water and fresh water irrigation,the soil salinity and the amount of desulphurized gypsum were significantly positively correlated.(3)The water content of clayey saline soil decreases significantly with the increase of the amount of sediment from the Yellow River.Among them,when the maximum combined application rate of sediment from the Yellow River was 50.33%,the soil water content was reduced by 23.32%and 46.24%respectively compared with CK treatment after salt water and fresh water irrigation.The water content of the clay saline soil also showed a decreasing trend with the increase of the desulphurization gypsum dosage.When the maximum desulphurization gypsum dosage was 3.2%,the water content of the soil was reduced by 13.83%and 35.85%compared with the CK treatment after salt water and fresh water irrigation.The soil water content increased linearly with the increase of the active potassium humate application rate.When the potassium humate application rate was 0.32%,the salt water and fresh water irrigation increased by 13.03%and 18.91%respectively compared with the CK treatment.Increase the soil's moisture adsorption capacity.(4)The combined application of yellow silt in clayey saline soil can significantly reduce the content of Na⁺,CI^-,Ca²⁺and SO₄^2-in the soil.When the combined application amount of yellow silt is 53.33%,the leaching effect of salt water on the above ions can reach 26.71%,16.18%,10.25%and 32.47%,the fresh water leaching effect can reach 59.77%,37.38%,40.00%and 51.88%.Active potassium humate and desulfurized gypsum can significantly reduce the content of Na⁺and CI^-in the soil.After fresh water irrigation,the best leaching effect can reach19.39%,15.03%,59.77%,and 32.83%,respectively.The content of Ca²⁺and SO₄^2-in the soil is positively correlated with the amount of desulfurized gypsum.(5)After applying the improved materials in the field,the yellowing sediment and potassium humate reduced the salt content of the soil surface.Among them,the S2 and T3treatments,which have the most significant impact,reduced CK by 25.85%and 12.24%respectively in the 0-10cm soil layer and 39.26%and 13.08%in the 10-20cm soil layer.Desulfurization gypsum increased the salt content of the soil surface.In the 0-10cm soil layer,the soil salt content of the P1,P2 and P3 treatments increased by 13.53%,26.36%,36.10%compared with CK.In the 10-20cm soil layer,P1,Compared with P2 and P3 treatments,CK increased by 29.77%,47.89%,and 58.25%,respectively.Both Yellow River Diversion Sediment and Desulfurization Gypsum reduce the surface water content of the soil.In the 0-10cm soil layer,the soil water content of S1,S2,S3 and P1,P2,P3 treatments are reduced by12.24%,6.12%,14.28%and respectively compared with CK 7.76%,11.41%,18.72%;10-20cm soil layer,S1,S2,S3 and P1,P2,P3 treatments soil water content were reduced by 9.86%,12.10%,11.21%and 6.09%,12.19%,respectively,compared with CK.7.31%.Active potassium humate increased the water content of the soil surface.The T3 treatment with the most significant impact increased CK by 32.28%and 34.97%in the 0-10cm and 10-20cm soil layers,respectively.(6)Compared with the CK treatment,the yield of S1,S2,and S3 wheat combined with yellow sediment diversion increased by 16.95%,33.89%,and 22.56%,respectively.Compared with CK treatment,the yield of T1,T2 and T3 wheat with potassium humate was increased by10.78%,27.01%,18.32%,respectively.Compared with the CK treatment,the yield of P1,P2and P3 wheat combined with desulfurized gypsum increased by 4.72%,5.20%and 8.11%,respectively.The combined application of yellow sediment,active potassium humate and desulfurized gypsum can significantly increase the yield of winter wheat,and the yellow sediment and potassium humate have the best yield-increasing effect.