| With the rapid development of industrialization and urbanization in Shanghai,the demand for land resources has increased rapidly.The urban construction has led to the rapid loss of agricultural land.The contradiction between supply and demand of land supply has forced us to find and exploit the reserve land resources.Chongming Island as the main reserve land resources and important strategic development space in Shanghai,the land development situation of concern.Chongming is located in the Yangtze River estuary,located in the intersection of fresh water and salt water,coupled with salt tide invasion,seawater intrusion and other factors,the soil soluble salt content has been in constant change.The study on the temporal and spatial distribution of soil salinity and the movement of water and salt in typical soil profiles is of great significance to Chongming’s agricultural production and water resources management policy.which is necessary for the development and maintenance of Shanghai ’s last ecological land.In this paper,the temporal and spatial distribution characteristics of soil salinity in Chongming area and the contents of soil water and salt transport in typical profile samples were analyzed.The temporal and spatial distribution characteristics of soil salinity in Chongming soil were analyzed by geostatistics and GIS.Factor analysis,the following conclusions:(1)The statistical analysis of EC value in surface soils at different periods in the study area showed that the change of soil electrical conductivity value was 112~531μs/cm in July,the average value was 178.25μs/cm,and the variation range of soil conductivity value in December 73~268μs/cm,the average value is 147.44μs/cm;July soil coefficient of variation coefficient of 37%,December soil conductivity coefficient of variation of 32%,are moderate intensity variation,by moderate strength of the outside world Interference;July soil conductivity values do not meet the normal distribution,in December soil conductivity values in line with the normal distribution.(2)Semi-variance function model The results show that the soil conductivity conforms to the spherical model in July,and the soil electrical conductivity in October is 0.06% and 13.51% respectively.The soil conductivities of the two months are Strong spatial correlation,mainly affected by structural factors,natural factors on its impact on the dominant position,the impact of human factors smaller.(3)The results show that the distribution of soil conductivity in July is similar to that of island and strip,and the trend is higher in the east and west than in the west.The soil conductivity in December is higher The distribution of soil spatial distribution is mainly located in the northwest and southeast regions.In July,compared with December,the area of soil conductivity increased mainly in the East Village,the Bao town,the Qianwei village,Yongan village,Xinguo and Yuejie village,that is,soil salinity increase area;the rest area was soil conductivity Reduced area,ie soil salt reduction area.The largest area of change is the southeastern part of Chongming,The area with the largest decrease in conductivity is in the area of Chenjia Town,and the area with the largest decrease in conductivity value is 321μs/cm,and the area with the largest increase in conductivity value is in the east of the east,Also showed island-like distribution,an increase of 123μs/cm.(4)The results of water changes in the typical soil profiles showed that the water content of the three soil profiles in the fort town,the town of Chenjia and Xinhai increased during the dynamic monitoring period in August and November,Soil water content is larger than in August.(5)The results of typical soil profile conductivity show that from the depth of soil layer,the electrical conductivity values of Baosteeli towns in August were significantly increased in vertical depth after the dynamic monitoring time in August The trend of decreasing,the inverted "V" font distribution,indicating that soil salinity mainly in the soil layer.During the dynamic monitoring time in November,the conductivity value of the town in the vertical direction showed a decreasing trend in the vertical depth,showing a "descending" type distribution,that is,the soil salinity was clustered on the soil surface.The monitoring data in December showed that the soil The results show that the soil salinity is mainly in the middle layer of the soil,but the monitoring of the two at the beginning of December,but also shows that the soil salinity is mainly in the middle of the soil.Day data show that the conductivity value of the point from the deep to the surface of the sharp surge in the forecast in December there will be the phenomenon of salt table aggregation;Xinhai town sample conductivity value in the vertical depth of the general upward trend,was "rising" type Distribution,and some monitoring time in the "drop" type and inverted "V" font,the local salt in November to gather in the deep soil-based.In the two periods,the soil electrical conductivity was found to be fluctuating in the soil.In general,the soil conductivity was higher than that in August.From the spatial positiondistribution point of view,the soil conductivity of Chenjia town is high,and the soil electrical conductivity of Xinhai town is lower,and the soil conductivity of the town is low,which indicates that the soil salt content of Chenjia Town is high,The town of salt content is low;soil salt content: dry land > woodland > farmland. |
