Effect Of Straw Mulching And Incorporation On Water And Salt Movement In Salinized Soil

Soil salinization is the major causes of declining agriculture productivity in the Dongying city of Shandong Province,China.In the circumstances of local shallow groundwater table,high evaporation,low precipitation and coupled with main upward movement of soil salt and severe salt accumulation in the surface soil in this area.In this study,we studied the effect of double straw mulching on soil water evaporation and salt transport through soil column simulation;at the same time,the effect of double straw mulching on soil water and salt distribution in farmland was studied by field experiment.to provide a theoretical basis for the improvement and utilization of coastal saline soil of Dongying city.In order to provide theoretical basis for the improvement and utilization of coastal saline alkali soil in Dongying city.The main results are as follows:1.The effects of different straw mulching methods on soil water evaporation and salt accumulation were studied by means of indoor soil column simulation experiment.(1)The effects of different straw mulching patterns on the daily evaporation of soil water were significantly different,and the inhibitory effect was T4>T5>T3>T1>T2.Under the same atmospheric evaporation condition,the different straw mulching patterns can reduce the cumulative evaporation of soil moisture,and the effect of T4 treatment(soil table and soil surface40 cm at the ratio of straw at the ratio of 2:1)is the most obvious;the cumulative evaporation is 76.13% lower than CK soil column,which greatly weakened the ability of bottom soil water to make up the water loss of tillage layer.The inhibition rate of T4 was76.12%,the inhibition rate was the largest,and the inhibition effect on soil water evaporation was the best.(2)In the leaching and infiltration stage,the effect of surface treatment on the salinity of the soil was different.And the treatment of T3(oil table and soil surface 40 cm at the ratio of straw at the ratio of 1:1)is the best,the soil desalination rate of 0-40 cm soil layer is14.83%.Other treatments were higher than control,but T2 treatment(Straw covered with straw under 40cm)0-40 cm soil desalination rate was lower than the control.In the stage of water evaporation,each treatment was inhibited to some extent,and the T4 treatment had the lowest salt recovery rate,which was far lower than that of the control.(3)The effect of straw double layer on soil water evaporation and soil back to salt was greater than that of straw surface cover and straw cover.And the effect of T4 treatment(soil table and soil surface40 cm at the ratio of straw at the ratio of 2:1)in the treatment of different straw mulching was the best.(4)There was a positive correlation between the accumulation of soil water and the cumulative amount of soil salinity.That is,the greater the cumulative evaporation of soil moisture,the greater the amount of soil salinity.2.The effects of straw mulching on soil water and salt transport were studied by field experiment.(1)Different straw mulching methods can reduce the evaporation of soil moisture,playing the role of water conservation,but the effect of soil moisture and aging was different.T1 treatment(surface covering)can inhibit the 0-40 cm soil layer of soil moisture evaporation,but the deep soil moisture inhibition effect is poor.T2 treatment(covering straw under the surface of 40cm)can improve the straw layer and above the soil water content,to a certain extent,and also has the function of keeping the soil moisture in the lower part of the interlayer.T4 treatment(soil table and soil surface 40 cm at the ratio of straw at the ratio of 2:1)has the best effect preservation on soil moisture in different double-layer straw mulching.(2)Different straw mulching methods could inhibit the soil back to a certain extent.The surface layer of straw inhibited the surface aggregation of salinity,and the effect of reducing salt content in 0-20 cm soil was better than that in soil.The inhibition rate was35.57%.T2,T3,T4 and T5 treatment can reduce the soil salinity of 0-40 cm soil layer,but also can control the salt content of deep soil at a low level.The effect of T2 treatment on the deep soil was the best and the inhibition rate was higher.The effect of T4 treatment on the surface soil was the best,and the inhibition rate was 54.85%.(3)The effects of straw mulching on soil sodium and chloride were studied by field micro experiment.Different straw mulching methods could reduce Na+ content and Cl-content in saline soil to a certain extent.T4 treatment could significantly reduce the Na+ content and Cl-content in the soil surface.T2 treatment could significantly reduce the Na+ content of20-60 cm soil layer and Cl-content of 20-40 cm soil layer.