GIS-mapping spatial distribution of soil salinity for Eco-restoring the Yellow River Delta in combination with Electromagnetic Induction

Abstract

a b s t r a c tSoil salinization is one of serious ecological problems around the world, which seriously restricts the stability of ecosystem and the economic development of agriculture. Mapping and monitoring spatial distribution of soil salinity is important for management of ecology and agriculture. This study was carried out to explore the spatial distribution of soil salinity in the Yellow River Delta using the portable device EM38-MK2 with geostatistical analysis. Apparent soil electrical conductivities were measured under four kinds of measurement modes (0.5H, 0.5 V, 1.0H and 1.0 V, respectively). The results revealed that electrical conductivity of 1:5 soil to water extract (ECe) varied from 0.965 to 1.872 dS m −1 for all sampled soil profiles, and the salinity of topsoil was the highest, which indicated that soil soluble salts accumulated to the surface. The salinity in the top layer showed strong spatial variability while salinities of other layers were moderate. Soil salinity displayed a significant zonal distribution, gradually decreasing with the increase of distance to the coastline. The regions with high ECa values were located in the north and the east of the study area, whereas regions with low ECa values were located in the south and the west parts. The correlation coefficient showed that salinities of adjacent two soil layers reached a significant level of 0.01, and gradually decreased with increasing soil depth. The linear interpretation models with ECa as independent variables and ECe as dependent variables for each depth were with R 2 between 0.828 and 0.919. The interpretation models, taking ECa and ECe of 0-15 cm depth as independent variables, and ECe of each layer in 15-100 cm depth as dependent variables, were with higher R 2 between 0.930 and 0.953. The mean error (ME) showed that there was small positive deviation in 40-100 cm whereas a high positive deviation in the topsoil (0-40 cm). The scatter plots also indicated that the models had better accuracy of salinity estimation in the top soil layers (0-80 cm). The results provides solid basis for eco-restoring in the Yellow River delta.

Detection model of soil salinization information in the Yellow River Delta based on feature space models with typical surface parameters derived from Landsat8 OLI image

“…The spatial distributions of soil salinization information are shown in Figure 7. The zones of soil salinization were mainly distributed in the northern Hekou district, eastern Kenli and Dongying district, which was consistent with the results of Liu et al (2016). In order to analyze and compare the inversion accuracies of the above 10 salinization detection indices, 32 field observation samples were used to calculate the correlation coefficients between the field observed value and inversed value, then to determine the optimal remote sensing monitoring model of soil salinization for the Yellow River Delta.…”

“…The study area is dominated by the continental monsoon climate characterized by an average annual temperature of 12.1 C and a ! 10 C accumulated temperature of 4200 C (Liu et al 2016). In addition, the average annual precipitation is 500-600 mm, most of which occurs in the summer.…”

Temporal dependence of potentiometric levels and groundwater salinity in alluvial aquifer upon rainfall and evapotranspiration

“…This increase is due to the salt leaching from the upper soil layers to groundwater due to rainfall (LIU et al 2016). Nevertheless, it is worth to note, from the visual inspection of Figure 4H, that the alluvial valley does not exhibits high salt concentrations, even for the drought periods.…”

“…Soils of these alluvial aquifers are susceptible to salt accumulation due to irrigation practices, rainfall and diffuse recharge variability and also from capillary flow from a shallow water table (LIU et al, 2016). In order to examine the effects of drought and precipitation on aquifer storage and to provide interpretation about the physical processes that control transient changes on water table levels, it is necessary to analyse the long-term measurements of groundwater levels (GARDNER; HEILWEIL, 2009), and the main information source about potential of hydrological stress within groundwater system (KHORASANI et al, 2016).…”

Three‐dimensional mapping of soil salinity in the southern coastal area of Laizhou Bay, China

“…Li, Shi, Webster, and Triantafilis (2013) predicted the spatial variation of soil salinity in paddy soils by adopting 3-D Co-kriging. Liu et al (2016) predicted the spatial distribution characteristics of soil salinity in the Yellow River Delta by using 3-D ordinary kriging.…”