Effects Of Blind Ditch On Law Of Soil Water And Salt Transport In Low-wetland And Growth Of Crop In Irrigation Districts Of Yellow River In Ningxia

Aiming at the bottleneck problem of high groundwater level,poor water washing salt effect and difficult improvement and utilization of low-lying saline-alkali land in Qing tong-xia,Ningxia,were incestigated.This paper studied and analyzed the dynamic changes of soil salinity on both sides of blind ditch with different spacing of saline and alkali land blind ditch the dynamic changes of soil water and salt in saline and alkali lands,soil salinity and salt content.The pH value and the influence on the growth and development of the weeping willow,screening and determining of the optimum blind ditch spacing suitable for the improved utilization of the low-lying saline-alkali land,provided scientific basis for the improvement and utilization of low-lying saline-alkali land in Ningxia and even in similar areas.The main findings are showed as follows:(1)The results of the experiment on the effect of different spacing blind ditch on soil moisture content showed that:from 2017 to 2018,with the decrease of blind ditch spacing,the water content of soil in each soil layer tended to decrease.In 2017,the soil moisture content of 3 m,6 m,9 m and 15 m spacing blind ditch decreased by 15.98%,10.54%,23.67%and 8.06%higher than that of CK.And in 2018,3 m,6 m and 9 m spacing blind ditch the soil moisture content treated with CK decreased by 3.80%,2.56%and 6.23%,15 m spacing blind ditch increased by 9.76%compared with CK.In conclude,9 m blind ditch treatment soil water content is the lowest,drainage and salt discharge speed is the fastest.(2)The results of the experiment on the effect of different spacing blind ditch on soil pH value show that:in 2017,with a decrease of blind ditch spacing,the pH value of soil in each soil layer showed an overall downward trend.And the pH value of soil treated by 3 m,6 m,9 m and 15 m spacing blind ditch decreased by 4.86%,5.28%,2.56%and 2.70%respectively;In 2018,6 m spacing blind ditch treated soil pH value compared to CK reduced 1.21%,3 m,9 m and 15m spacing blind ditch treated soil pH value higher than CK 0.46%,0.78%and 0.05%,respectively.Thus,the 6 m blind ditch spacing worked best on the reduction of soil pH.(3)The results of the experiment on the effect of different spacing blind ditch on soil salinity showed that:in 2017,the soil salinity of 3 m,6 m,9 m and 15 m spacing blind ditch decreased by 4.37%,7.77%,32.23%and 15.17%higher than that of CK.In 2018,3m,6 m,9 m and 15 m spacing blind ditch treated soil salinity was lower than CK reduction of 46.12%,39.61%,52.67%and 28.77%.Thus,9 m blind ditch treatment of soil salt content is the lowest,3 m and 6 m blind ditch treatments are secondry.(4)The results of different spacing blind ditch on the growth and development index of weeping willow showed that in 2017,the diameter of 3 m,6 m,9 m and 15 m blind ditch treatment willow was increased by 69.94%,75.51%,80.52%and 69.57%higher than that of CK,respectively,and the tree height of 3 m,6 m,9 m and 15 m blind ditch treatment willow was increased by 28.57%,3 8.86%,58.11%and 24.86%higher than that of CK,respectively,the crown breadth of 3 m,6 m,9 m and 15 m blind ditch treatment willow was increased by 39.31%,46.89%,51.57%and 43.37%higher than that of CK,respectively.In 2018,the diameter of 3 m,6 m,9 m and blind ditch treatment willow was increased by 58.82%,66.97%,32.82%and 66.82%,higher than that of CK,respectively,and the tree height of 3 m,6 m,9 m and 15 m blind ditch treatment willow was increased by 30.99%,36.7%,52.97%and 22.64%,respectively,the crown breadth of 3 m,6 m,9 m and 15 m blind ditch treatment willow was increased by 30.38%,39.80%,46.51%and 28.05%higher than that of CK,respectively.Thus,the effect of 9 m on the growth of weeping Willow was the most significant,6 m and 3 m spacing blind ditch treatments ware lesser.Effects of different spacing blind ditch on water and salt migration and plant growth and development in low-lying saline-alkali land the results showed that the 9 m spacing is the best blind ditch spacing design of low-lying saline-alkali land,which can effectively solve the problem related to high groundwater level,poor water washing salt effect and difficult improvement and utilization in low-lying saline-alkali land in Qingtongxia.Moreover,it could also provide a scientific basis for the treatment of low-lying saline and alkali land in similar areas.