Characteristics Of Brackish Water Infiltration And Distribution Of Soil Water And Salt In Straw Reusing

The rational exploitation and utilization of brackish water is of great significance to realize the sustainable development of agriculture in China.In order to study the comprehensive utilization effect of brackish water and straw,one-dimensional vertical infiltration test was carried out in the room to study the brackish water infiltration characteristics,the way of salt ion migration and the influence on soil,The main conclusions are as follows:?1?Effects of Straw Reusing Mode on Infiltration Characteristics and the Distribution of Soil Water and SaltWith the increase of the amount of straw and the increase of the thickness of straw,the accumulated infiltration and wetting distance gradually decreased under the same irrigation time.Straw returned to field showed strong water resistance,and under the influence of straw,soil saturated water content increased with the amount of straw,but the soil moisture content below the layer was opposite.Influenced by surface water,different treatments have a salt accumulation in surface layer,soil salt content of straw layer increased sharply;as for 1cm,4cm,7cm three degree of straw crushing levels,the 4cm win the best resistance;straw decomposition increased the permeability of soil?2?Characteristics of Different Salt Water Infiltration and Distribution of Soil Water and Salt in Straw Reusing.Under the same infiltration time,the cumulative infiltration amount with the salinity of 3g/L as the cut-off point increases with the salinity decreased after increasing,changes of wetting front is similar;When the salinity is 3g/L,the soil will remain high water content;The salt content of soil increased with the increase of salinity.When the degree of mineralization was more than 4g/L,the brackish water had little effect on the leaching of soil column.At the same depth,the sodium adsorption ratio and soil water content has a negative correlation.And the correlation between soil salinity and sodium adsorption ratio was not significant.?3?Infiltration Characteristics of Different Soil Factors and Distribution of SoilWater and Salt under Straw ReusingWhen the soil bulk density increases,the infiltration capacity of the soil decreases,so as to the cumulative infiltration amount,the wet front migration distance and the infiltration rate.Under the same depth,the decrease in soil porosity increasesthe resistance to moisture migration,The higher the soil bulk density,the smaller the soil moisture content,the less the leaching range of the salt;The greater the initial soil moisture content,the higher the soil wetting front potential,and the average potential gradient between the wet front and the dry soil the smaller,The smaller the gradient,the lower the soil infiltration rate,the less the increment of water content,the smaller the cumulative infiltration volume;The hydraulic conductivity of the heavy soil is less than the light one,and the smaller infiltration capacity.?4?Characteristics of Soil Salt Ion DistributionIn the whole,ions have a similar distribution pattern,the concentration of Ca²⁺,Na⁺,Mg²⁺ and Cl^-,was "C" shaped distribution in the soil profile,and the content of K⁺ is gradually increasing with the soil deepening in the whole profile;Straw reusing increased the accumulation of ions in the soil.