Spatial variability and pattern analysis of soil properties in Dehui city, Jilin province

Based on regionalized variable theory, semivariograms of geo-statistics wereused to research the spatial variation of soil properties quantitatively. The results showed thatthe semivariogram of soil organic matter is best described by spherical model, the best model forsemivariograms of soil total N and available K is exponential models and that of available P belongsto linear with sill model. Those soil properties have different spatial correlations respectively,the lag of organic matter is the highest and that of available P is the lowest, the spatialcorrelation of N and available K belongs to moderate degree. Spatial heterogeneities are differenttoo, the degree of organic matter and total N are higher, the degree of available K is in the nextplace and that of available P is the lowest. Influenced by the shape, topography and soil of thestudy area, all isotropies of available P are obvious in all directions while anisotropies of othersare manifested. According to the analytical results, supported by GIS, Kriging and IDW methods areapplied to describe and analyze the spatial distribution of soil properties. The results indicatethat soil organic matter, total N and available K are distributed regularly from northeast tosouthwest, while available P is distributed randomly.

Influence of groundwater level change on vegetation coverage and their spatial variation in arid regions

Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.

Monotone Regression and Correction for Order Relation Deviations in Indicator Kriging

The indicator kriging （IK） is one of the most efficient nonparametric methods in geo-statistics. The order relation problem in the conditional cumulative distribution values obtained by IK is the most severe drawback of it. The correction of order relation deviations is an essential and important part of IK approach. A monotone regression was proposed as a new correction method which could minimize the deviation from original quintiles value, although, ensuring all order relations.

Space-Temporal Variation in Underground Water Some Quality Parameters in Klodzko Water Intake Area Using Statistical and Geostatistical Methods （SW Part of Poland）

This paper presents selected results of research connected with the development of a （3D） geostatistical hydrogeochemical model of the Klodzko Drainage Basin, dedicated to the spatial and time variation in the selected quality parameters of underground water in the Klodzko water intake area （SW part of Poland） [1-6]. The research covers the period 1977-2012. Spatial analyses of the variation in different quality parameters, between others, Fe [gFe/m3], Mn [gMn/m3], ammonium ion [gNH4＋/m3] contents and oxidation capacity [gO2/m3], were carried out on the basis of the chemical determinations of the quality parameters of underground water samples taken from the wells in the water intake area [2-4]. Spatial and time variation in the parameters was analyzed on the basis of archival data （period 1977-1999） for 22 （pump and siphon） wells, later data obtained （November 2011） from tests of water taken from 14 existing wells and the latest data （January 2012） acquired from 3 new piezometers, which were made in other locations in the relevant area. Thematic databases, containing original data on coordinates X, Y （latitude, longitude） and Z （terrain elevation and time-years） and on regionalized variables, i.e. the underground water quality parameters in the Klodzko water intake area determined for different analytical configurations （22 wells, 14 wells, 14 wells ＋ 3 piezometers）, were created [2]. Both archival data （acquired in the years 1977-1999） and the latest data （collected in 2011-2012） were analyzed. These data were subjected to spatial analyses [2-6] using statistical and geostatistical methods [7-12]. The evaluation of basic statistics of the investigated quality parameters, including their histograms of distributions, scatter diagrams between these parameters and also correlation coefficients r, were presented in this article. The directional semivariogram function and the ordinary （block） kriging procedure were used to build the 3D geostatistical model. The geostatistical parameters of the theoretical models of directional semivariograms of the studied water quality parameters, calculated along the time interval and the well depth （taking into account the terrain elevation）, were used in the ordinary （block） kriging estimation. The obtained results of estimation, allowed to determine the levels of increased values Z＊ of studied underground water quality parameters [2, 4-6]. Generally, the behaviour of the underground water quality parameters has been found to vary in space and time. Thanks to the spatial analyses of the variation in the quality parameters in the Klodzko underground water intake area some regularities （trends） in the variation in water quality have been identified.

Groundwater Quality Evaluation Using GIS Based Geostatistical Algorithms

Groundwater quality is a major environmental aspect which needs to be analyzed and managed depending on its spatial distribution. Utilization of insufficient management of groundwater resources in Gaza Strip, Palestine, produces not only a reduction in quantity but also deterioration in quality of groundwater. The aim of this study is to provide an overview for evaluation of groundwater quality in the Gaza Strip area as a case study for applying spatially distributed by using Geographic Information System (GIS) and geostatistical algorithms. The groundwater quality parameters, pH, total dissolved solids, total hardness, alkalinity, chloride, nitrate, sulfate, calcium, magnesium, and fluoride, were sampled and analyzed from the existing municipal and agricultural wells in Gaza Strip;maps of each parameter were created using geostatistical (Kriging) approach. Experimental semivariogram values were tested for different ordinary Kriging models to identify the best fitted for the ten water quality parameters and the best models were selected on the basis of mean square error (MSE), root mean square error (RMSE), average standard error (ASE), and root mean square standardized error (RMSSE). Maps of 10 groundwater quality parameters were used to calculate the groundwater quality index (GWQI) map using the index method. In general, the results showed that this integrated method is a sufficient assessment tool for environmental spatially distributed parameters.

Characterizing spatial distribution and sources of heavy metals in the soils from mining-smelting activities in Shuikoushan,Hunan Province,China

The spatial variation of heavy metals in the soils in Shuikoushan mining-smelting area, Hunan Province, China, was investigated using multivariate and geo-statistic analysis. A total of 106 composite soil samples were collected in an area of about 100 km^2. Concentrations of total As, Cd, Pb, Zn, Cu and Cr were measured using inductively coupled plasma mass spectrometry （ICP-MS）. Arsenic and Pb were found to have a common source, indicating the same sources and spreading processes, such as aerosols and airborne particulates from smelting chimneys. Airborne sources from smelting chimneys contributed greatly to Cd in the area, which demonstrated the same dispersion pattern as As and Pb. However, two hot spots of Cd around smelters were possibly enlarged by wastewaters, demonstrating another important source of Cd in Shuikouhsan. Geo-statistic interpolated mapping demonstrated that hotspots of Zn were only found proximal to the large smelters, suggesting that Zn primarily came from the chimneys of larger smelters. The major Cu hot-spots appeared closely to the tailing dam, indicating that weathering and leaching of tailings were the major sources of Cu contamination in Shuikoushan. Our findings indicated that airborne volatile particles and aerosols contributed the most to As, Cd, Pb, Zn and Cu contamination, while Cd and Cu may also derive from the discharge of wastewater from smelters and the leaching of tailings, respectively,

ArcGIS-Based Rural Drinking Water Quality Health Risk Assessment

Aiming at the unsafe of water quality which is the core problem in rural drinking water safety, the study col-lected 221 water samples of rural drinking water sources in Ya'an and detected the concentrations of the car-cinogen and the non-carcinogen. Based on the analysis of water environment characteristics and the identifi-cation of water environment health risk source of Sichuan Ya’an City, which includes seven counties and a district and is the typical region of the western margin of Sichuan Basin, this study calculated and analyzed the carcinogenic risk (R) and non-carcinogenic risk (hazard index, HI) by applying the health risk model recommended by the US National Research Council of National Academy of Science. Then, taking advan-tage of the geo-statistic spatial analysis function of ArcGIS, this study analyzed the assessment result data (R and HI), selected the proper interpolation approach and educed R and HI spatial distribution maps of the study area. R and HI of the single factor and integrate factors were evaluated and thus obtained the following conclusions: For one thing, the cancerous risk indexes of the vast majority of water sources (about 94%) is the level of 10-7 and it belong to the safety extension. The main carcinogen in the water sources are As, Cr6+ and Pb, their concentrations are in the ranges of 0.004-0.01, 0.005, 0.01mg/l respectively and such water source mainly distributed in Yucheng district and Mingshan county. For another, the non-cancerous hazard indexes of the vast majority of water sources (about 98%) is also less than the limit value 1 and will not harm the local residents. The health risk of non-carcinogen comes mainly from As and fluoride, their concentra-tions are in the ranges of 0.004-0.01 and 0.1-4.2mg/l respectively. The results of the integrate factors health risk assessment showed that the total cancerous risk were still at the level of 10-6, only 12 drinking water source investigation sites (5%) exceeded the drinking water management standard value of EPA (the limit value is 10-6);the total non-cancerous hazard indexes are still in the range of 10-2-10-1, and will not harm the local residents either, only 18 drinking water source investigation sites (8%) exceeded the drinking water management standard value of EPA(the limit value is 1).The densely populated areas such as Yucheng Dis-trict, Tianquan County, Yingjing County and Shimian County are where the four contaminating materials, i.e., As, Cr6+, Pb and fluoride should be monitored with emphasis. Study results disclosed the health risk control indexes of source water quality of the studied area and thus provided the scientific basis for the water quality control of water sources. This study had worked efficiently in practice. Compared with the same kind of methods which had been found, the paper had the outstanding results for the health risk assessment of the rural drinking water safety.

Evaluation of Spatial Variability of Soil Properties in a Long-Term Experimental Tobacco Station in Southwest China

Analysis of the spatial variability of soil properties is important to arrange the experimental treatments in the experimental station. This paper aims to study the spatial structure of soil variables and their distribution in the Pengshui tobacco experiment station in Chongqing, China. Soil samples were taken from 289 soil points on 20 m grid in March 2012. Twenty-two soil chemical and physical properties were analyzed by classical statistical and geo-statistical methods. Soil pH, cation exchange capacity （CEC）, total phosphorus （TP）, available phosphorus （AP）, zinc （Zn）, magnesium （Mg） and sulphur （S） have the strong spatial dependence, with nugget/sill ratios of less than 25%. The others have the moderate dependence with nugget/sill ratios of 26.17% to 71.04%. Ranges of the spatial correlation varied from 51.30 m for chlorine （C1） to 594.90 m for TP. The clearly patchy maps of the nutrients showed the spatial distributions of the soil variables, which can be used for better management of experimental treatments, achieving reliable exoerimental results in the tobacco exnerimental station.Highlight： Scientific experimentation assumes the existence of random variability for soil attributes. This research was to evaluate the spatial variability of soil chemical and physical attributes and to interpolate the spatial distribution of soil properties in the tobacco experimental station in Chongqing. The result of this work can be used for the agricultural management of tobacco cultivation.

Spatial Variability Analysis of Soil Nutrients Based on GIS and Geostatistics:A Case Study of Yisa Township, Yunnan, China

Hani rice terraces system is one of the Globaly Important Agricultural Heritage Systems （GIAHS） pilot sites selected by FAO. Soil nutrients are an important symbol of soil fertility, and play an important role in the sustainable utilization of land. Based on geo-statistics and GIS, the spatial variation of pH, organic matter, total nitrogen, alkaline hydrolyzable nitrogen, available phosphorus and available potassium in the soil in Yisa （a town in Honghe County, Yunnan Province） was studied. The results show that the spatial variability of pH, organic matter, total nitrogen, alkaline hydrolyzable nitrogen and available potassium exhibited medium spatial variability, and the coefficients of variation are 12.54%, 40.14%, 40.00%, 34.89%, and 40.00% respectively. Available phosphorus exhibited strong spatial variability, and the coefifcient of variation is 102.13%. The spatial variation of pH, organic matter, total nitrogen, alkaline hydrolyzable nitrogen and available potassium fit the index mode, however, the spatial variation of available phosphorus ifts the spherical model. Total nitrogen, available phosphorus and available potassium were greatly affected by soil structural factors, while pH, organic matter and alkaline hydrolyzable nitrogen were affected by both structural and random factors. The spatial distribution of soil nutrients in Yisa was intuitively characterized by Kriging interpolation. It is very important to understand the spatial distribution of soil nutrients, which wil provide the guidance for adjusting agricultural management measures such as fertilization.

Modelling and predicting the spatial dispersion of skin cancer considering environmental and socio-economic factors using a digital earth approach

Almost all causative factors of diseases depend on location.The Digital Earth approach is suitable for studying diseases globally.Geospatial information systems integrated with statistical models can be used to model the relationship between a disease and its causative factors.Through modelling,the most important causative factors can be extracted and the epidemiology of the disease can be observed.In this paper,skin cancer(the most common type of cancer)has been modelled based on its causative factors,including climate factors,people’s occupations,nutrition habits,socio-economic factors,and usage of chemical fertiliser.To fit the model,a data framework was first designed,and then data were gathered and processed.Finally,the disease was modelled using Generalised Linear Models(GLM),a statistical model based on the location of the factors.The results of this study identify the most important causative factors together with their relative priority.Furthermore,a model was used to predict the change in skin cancer occurrences caused by a change in one of its causative factors.This work illustrates the ability of the model to predict disease occurrence.Thus,by using this Digital Earth approach,skincancer can be studied in all the key countries around the world.

Spatial heterogeneity of available zinc, copper, and manganese in Xiangcheng Tobacco Planting Fields, Henan Province, China

Geostatistical methods were used in combina-tion with geographical information system(GIS)technol-ogy to analyze the spatial distribution characteristics of available zinc,copper,and manganese in the Xiangcheng tobacco planting fields,Henan province,China.Analysis of the isotropic variogram indicated that the Zn semivar-iogram was well described with the Gaussian model,with the distance of spatial dependence being 900.7m;while the Mn semivariogram was well described with spherical models,with the distance of spatial dependence being 14060m;and,the Cu semivariogram was well described with exponential models,with the distance of spatial dependence being 27860.7m.Mn and Zn were strongly spatially dependent,with the C_(0)/sill being 0.014 and 0.147 in this given region;while Cu was moderately spatially dependent,with the C_(0)/sill being 0.3528.With the kriging analysis,the spatial distribution maps of contents of these three trace elements in the Xiangcheng tobacco planting regions was drawn with the Arcview software.It was found that the soils with higher content of Mn were mainly distributed in the high mountains of the southern part of the given regions,while the soils with higher content of Cu were mainly distributed in the south,decreasing from the south to the north.The soil with contents of Zn in the range of 0.76–1.33 mg/kg existed in the high mountains of the west and middle parts of the investigated regions,accounting for 76.11%of the whole area.