The Effects Of The Modified Sand Reclamation On The Water And Physical Properties Of Coastal Clay Saline Soil

China is a large agricultural country.With the continuous growth of the population,the demand for food continues to grow,and the per capita possession of land is decreasing.The contradiction between the supply and demand of land is increasing.Various types of salinealkali soil as potential backup resources can be used to improve the area of cultivated land,reduce the pressure on land resources,and increase food production.In view of the two serious problems of soil salinization in the Yellow River Delta and the large amount of engineering sediments in the Yellow River irrigation area,the field and laboratory tests for the improvement of clay sediments in the clay soil were carried out.The changes in soil moisture and physical properties,through a series of soil column simulation tests on the effects of the Yellow River Sediment on the pore state,water characteristics,saturated hydraulic conductivity,etc.,of clay soils,basically clarified that different sand allocations were applied to clay soils.The mechanism of soil moisture and physical properties,such as pore type and ratio,and soil saturated hydraulic conductivity,are the main findings of the study as follows:(1)According to the monitoring data of water and sediment in the irrigation area of the Yellow River and Yellow River,the influence of the operation of the Xiaolangdi Reservoir on the sediment yield and sediment particle size of the Yellow River irrigation area in the Yellow River Delta was studied.The results show that after the operation of Xiaolangdi Reservoir,the annual average amount of sand diverted from the irrigation districts of the Yellow River to the Yellow River drastically decreased,and the sand particle size increased year by year,resulting in siltation of the main canal and affecting the normal operation of the irrigation district.(2)The results of field trials showed that after the clay soil was modified with slime saline soil,the content of fine sand grains >0.05 mm in the soil was significantly increased,and the clay content of <0.002 mm was reduced.The difference between different treatments was significant;the soil bulk density was adjusted with the amount of sediment.With the increase and decrease,the total porosity of the soil,especially the volume and proportion of the ventilation pores of the soil increased,the soil pore status was significantly improved,the soil saturated hydraulic conductivity increased significantly,and the water permeability of the clay soil increased,which was beneficial to Rapid leaching of soil salinity.(3)Through the soil pressure membrane test of different soil-sand ratio simulation soil columns,the variation rules of soil moisture and pore conditions under different sediment concentration variations were studied,and the extremely fine sand and soil ventilation pores and capillary pores were established.The mathematical relationship between voids of different types,such as void voids and soil macropores,clearly defines the effect of sand modification on the pore state of clay soil.(4)Based on the results of laboratory tests of saturated hydraulic conductivities of soil columns with different soil-sand ratio simulations,the mathematical relationship between the ultra-fine sand and soil saturated hydraulic conductivity was established,and it was clarified that the sand-enhancement was applied to the saturated saline-soil saturated soil.The mechanism of the water rate effect.(5)After the clay soil was modified with clay soil,the soil water and salt dynamics in the soil profile were significantly different from the sand layer and the sand layer.The soil salt content of 0-30 cm is significantly lower than that of the sediment layer.The effect of sand allocation on surface soil salt accumulation is obvious,but the soil moisture content is also reduced to some extent.It also has a very obvious promotion effect on the growth and yield of winter wheat.(6)The yield of CK,NS1 and NS2 was 4254.78kg/ha,5657.88kg/ha and 7174.8kg/ha respectively after the improvement of clay saline soil with sand.Compared with CK,the yield of wheat treated with NS1 and NS2 increased by 32.98% and 62.63% respectively,and the results showed that the improvement of sand treatment had a significant promoting effect on the yield of winter wheat.