Effects Of Sand Blending On The Adsorption And Leaching Of Salts And Ions In Coastal Clay Saline Soil

Affected by unreasonable exploitation and utilization of human beings and natural disasters,soil salinization area is increasing,soil salinization has become a serious ecological and environmental problem faced by all countries in the world,soil salinization management has become an important part of the development plans of many countries.Coastal clay soil is an important type of soil in the Yellow River delta,the heavy clay soil,the large number of accumulation of soil salt?Na⁺?,is a key problem for improved using glue solonchak.Sediment deposition,treatment and utilization are difficult in the Yellow River delta area.It is of great significance to study the effect of sand distribution improvement on the adsorption and leaching properties of clayey saline soil,so as to improve the yield of clayey saline soil,promote the sustainable development of the economy of the Yellow River delta,guarantee the national food security and social stability.In order to study the influence mechanism of yellow sediment on coastal clayey saline soil salinity and ion adsorption and leaching,this paper takes the clayey saline soil in the Yellow River delta region as the research object,using the large amount of sediment deposition in the irrigation area of the Yellow River delta which need to deal with,the binhai glue solonchak indoor and field experiment of sand with improved.In the laboratory test,soil water adsorption test and soil salt adsorption test were carried out by the method of soil column simulation.The main research was on the effect of sediment mixing on soil water adsorption,salinity and ion adsorption leaching,and the field test was carried out to determine the appropriate sediment mixing range.The main results of this study are as follows:?1?There is a significant difference in particle composition between yellow sediment and clayey saline soil.The content of 1-0.05mm sand particles in yellow sediment is 95%,and the clay content with particle size<0.005mm is 0%,while the content of 1-0.05mm sand particles in clayey saline soil is only 3.8%and the clay content is up to 39.8%.With the increase of soil sediment content,the contents of sand and silt in the mixed soil increased linearly,while the contents of clay decreased linearly.?2?The salt content and ion composition of the yellow sediment were significantly different from that of the viscositic saline soil.With the increase of the soil sediment content,the salt content of the soil decreased by 70.1%from the total viscositic saline soil to the total sediment.The proportions of Na⁺,Mg²⁺,Ca²⁺and SO₄^2-in the positive?negative?ions in the soil decreased significantly,the ratio of Na⁺to the total cation in the soil decreased by 19%,and the proportions of Mg²⁺,Ca²⁺and SO₄^2-in the cation decreased by 2%,10%and 3.3%,respectively.The proportion of main salt ions in the soil in the anion?cation?gradually decreased,especially Na⁺and Cl^-decreased by 26.3%and 8.5%,respectively.?3?The improvement of sediment distribution can reduce the adsorption capacity of clay saline to water and salt ions,and saturated water content are negatively correlated with the sediment distribution.There was a significant correlation between the content of soil sand and the content of salt and ions,among which the Na⁺,Ca²⁺and SO₄^2-in soil gradually decreased with the increase of the content of soil sand.A linear regression model between soil sand content and Na⁺and Cl^-content of salt ions was established.When the soil sediment content was lower than 32.0kg/m²,the contents of Na⁺and Cl^-gradually decreased.?4?With the increase of the soil and sediment,the salty water and deionized water after washed out after leaching,the change of the soil salt ion ratio and composition are significant differences?p<0.05?,research shows that the improved with sand can effectively inhibit the soil adsorption of salt ions,improving soil pore structure,promote salt-leaching,reduce the relative content of Na⁺and Cl^-in the soil,improving soil Ca²⁺,Mg²⁺,K⁺the relative content of nutrient elements.?5?After the improvement of field sand distribution,the soil water holding capacity gradually decreases with the increase of the amount of sand distribution.Compared with CK treatment,the surface soil salinity,Na⁺and Cl^-contents gradually decreased with the increase of soil sediment allocation 0-20cm,and the differences reached a significant level?P<0.05?.With the increase of soil sediment distribution,the relative content of total surface soil salinity?Na⁺+Cl^-?gradually decreased.In 2016 and 2017,S7 treatment decreased by 14%and 11%respectively compared with CK treatment.?6?After the improvement of sand distribution,wheat yield in the field was significantly increased?P<0.05?.In 2016,wheat yield of S5 treatment was 64.4%higher than that of CK treatment.In 2017,the wheat yield in S2 treatment increased by 29.3%compared with that in CK treatment.In 2018,the wheat yield in S5 treatment increased by 33.9%compared with that in CK treatment.