Experimental Study On Salt Draining Effect Of Different Covered Gap

For the high-degree of soil salinity and groundwater salinity and the condition of high water level,in the study both at home and abroad drainage row of salt alkali instead,on the basis of technical experience,introduce the drainage discharge salt technology in ningxia hui heavy saline soil improvement,mainly study the drainage different spacing(T1-3 m,T2-6 m,T3-9 m,T4-15 m)and different depth Settings(H1-0.8 m,H2-1.0 m,H3-1.2 nm),salinization of soil physical and chemical properties in the region and the influence of the growth condition of weeping willow.And the main conclusions are as follows:(1)Different drainage pitch setting conditions,underground water level descending speed T1>T2>T3>T4.Different drainage under the condition of setting depth,the underground water level drop speed H3>H2>H1.The early stage of the drainage of groundwater levels fall slowly,late drainage,groundwater drawdown speed.And between the different processing,ground water levels fall velocity difference is bigger(2)Drainage treatment can obviously decrease the soil PH value,but blind ditch spacing and buried depth on the influence of PH change does not present the obvious regularity.Under the condition of different drainage spacing,T1,T2 similar degree and effect on soil salt content is much higher than T2,T3,T3 and T4 drainage extent similar effects on soil salinity.Different drainage buried depth setting conditions H2,H3,similar degree of impact on soil salt content,and significantly higher than the H1.(3)Analysis after water leaching,drainage between the spatial variation of the soil salt shows:under the condition of different drainage pitch setting,drainage soil desalting uniformity between T1>T2>T3.,under the conditions of different drainage depth setting drainage soil desalting uniformity between H1<H2<H3.(4)Comparing experimental zone and controlled zone of different levels of soil salt content change trend of the year,in the years of salinity change:different drainage pitch setting conditions,0 to 20 cm similar soil improvement effect of T1,T2,T3,T4 of similar;0-60 cm and 0-100 cm soil layer of T1,T2 and T3.Different drainage depth set conditions,0?20 cm soil layer of H1 and H2,significantly lower than the H3;0-60 cm and 0-100 cm soil layer of H2 and H3,significantly higher than the H1(5)Analyzing and comparing different drainage(tube)spacing and depth Settings on experimental zone weeping willow growth index shows that the influence of different drainage spacing condition,T1,T2 and T3 similar influence on the weeping willow tree height and diameter at breast height,greater than the T4 of tree height,DBH growth rate;T2,T3,T4 of similar degree of the influence of the crown,is far less than the influence of T1.Different drainage buried deep under the condition of setting H2,H3 effects on free height,diameter at breast height,crown similar degree,far greater than the influence degree of the H1.Based on the above anisotropic index,recommended drain distance of 3 m to 9 m,depth of 1 m to 1.2 m for the Ningxia Wu Zhong saline ditch(canal)set a reasonable range of salt discharge.