scholarly journals Application of kriging techniques for assessing the salinity of irrigated soils: the case of El Ghrous perimeter, Biskra, Algeria

2019 ◽  
Vol 9 ◽  
Author(s):  
Mohamed Amine Abdennour ◽  
Abdelkader Douaoui ◽  
Abdelhamid Bradai ◽  
Amel Bennacer ◽  
Manuel Pulido Fernández
Keyword(s):  
Soil Salinity ◽  
Ordinary Kriging ◽  
Indicator Kriging ◽  
Spatial Trend ◽  
Risk Areas ◽  
Geostatistical Techniques ◽  
Anthropogenic Processes ◽  
Irrigated Perimeter ◽  
Made In ◽  
Irrigated Soils

In semi-arid and arid areas, soil salinity has adverse effects both on the environment and agricultural production. The main causes of this salinization come from natural or anthropogenic processes, which is certainly an environmental problem that affects more than 20% of the world's land. This study was made in order to map the spatial distribution of soil salinity of the irrigated perimeter of El Ghrous in southeastern Algeria. These maps were performed based on data collected from 190 soil samples from 0 to 15 cm deep. We used ordinary kriging (OK) to analyze the spatial variability of soil salinity, while indicator kriging (IK) was used to analyze salinity versus threshold values. The salinity map predicted by the electrical conductivity (EC) values using the ordinary kriging (OK) method showed the different classes of salinity according to Durand's classification with moderately saline 3rd order dominance, while the unsalted soil (EC &lt; 0.6 dS m<sup>-1</sup>) represents a very low percentage (1.5%). The indicator kriging (IK) was carried out by four thresholds which correspond to the salinity class limits: EC &gt; 0.6, EC &gt; 1, EC &gt; 2, EC &gt; 3, and EC &gt; 4 dS m<sup>-1</sup>, for developing probability maps to determine risk areas. This study has shown the spatial trend of soil salinity by geolocation of different classes, and to carry out risk maps using geostatistical techniques.

scholarly journals Geostatistics as a tool to reduce the sampling effort in forest inventories

2021 ◽  
pp. 174-179
Author(s):  
Myrcia Minatti ◽  
Carlos Roberto Sanquetta ◽  
Sylvio Péllico Neto ◽  
Ana Paula Dalla Corte ◽  
Vinicius Costa Cysneiros
Keyword(s):  
Forest Inventory ◽  
Ordinary Kriging ◽  
Simple Random Sampling ◽  
Exponential Model ◽  
Indicator Kriging ◽  
Sampling Effort ◽  
Thematic Maps ◽  
Visual Interpretation ◽  
Forest Inventories ◽  
Geostatistical Techniques

Geostatistics is one of the tools applied to investigate the spatial variability of forests to reduce costs and recognize the best productivity areas for planning. This study aimed to test the performance of geostatistical techniques in reducing the sampling effort in forest inventories. For this purpose, we used the height of dominant trees as a discriminator of the homogeneous strata to obtain a better representation of the productivity within the forest stands. We carried out the study in Pinus taeda L. stands in the Center-South of Paraná, Brazil, by using plots from a forest inventory allocated with the systematic process. Then, we tested three models to determine the site curves (Schumacher, Chapman-Richards 2, and 3 coefficients) with the thirty-seventh year being the reference age. To model the spatial patterns of the dominant height, we used the ordinary kriging, and, after that, we generated the thematic maps of the site classes. Similarly, we used the indicator kriging which allowed obtaining the probabilities of high, medium, and low productivity sites. The processing of the stratified sampling, with the support of the visual interpretation of the images, allowed us to define five strata according to productivity. Results showed that ordinary kriging is effective in defining the productivity classes. Along with geostatistical techniques, it produces more homogeneous strata and reduces the errors of the forest inventory. Moreover, the best-selected model was the Chapman-Richards (3 coefficients) for the site curves. The exponential model was the best model to identify the best areas of the probability of occurrence of sites with higher productivity. The efficiency of indicative kriging generated thematic maps to delimit the likely locations of the most promising sites. Overall, geostatistics proved to be efficient concerning error when compared to simple random sampling.

scholarly journals Improvement of Spatial Modeling of Cr, Pb, Cd, As and Ni in Soil Based on Portable X-ray Fluorescence (PXRF) and Geostatistics: A Case Study in East China

2019 ◽  
Vol 16 (15) ◽  
pp. 2694 ◽  
Author(s):  
Xia ◽  
Hu ◽  
Shao ◽  
Xu ◽  
Zhou ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Hot Spots ◽  
Ordinary Kriging ◽  
Eastern China ◽  
Indicator Kriging ◽  
Polluted Water ◽  
X Ray ◽  
Soil Heavy Metals ◽  
Metals Pollution ◽  
Heavy Metals Pollution

To verify the feasibility of portable X-ray fluorescence (PXRF) for rapidly analyzing, assessing and improving soil heavy metals mapping, 351 samples were collected from Fuyang District, Hangzhou City, in eastern China. Ordinary kriging (OK) and co-ordinary kriging (COK) combined with PXRF measurements were used to explore spatial patterns of heavy metals content in the soil. The Getis-Ord index was calculated to discern hot spots of heavy metals. Finally, multi-variable indicator kriging was conducted to obtain a map of multi-heavy metals pollution. The results indicated Cd is the primary pollution element in Fuyang, followed by As and Pb. Application of PXRF measurements as covariates in COK improved model accuracy, especially for Pb and Cd. Heavy metals pollution hot spots were mainly detected in northern Fuyang and plains along the Fuchun River in southern Fuyang because of mining, industrial and traffic activities, and irrigation with polluted water. Area with high risk of multi-heavy metals pollution mainly distributed in plain along the Fuchun River and the eastern Fuyang. These findings certified the feasibility of using PXRF as an efficient and reliable method for soil heavy metals pollution assessment and mapping, which could contribute to reduce the cost of surveys and pollution remediation.

scholarly journals Review of the Kriging Technique Applications to Groundwater Quality

2021 ◽  
Vol 27 (12) ◽  
pp. 23-32
Author(s):  
Hayat Azawi ◽  
May Samir Saleh
Keyword(s):  
Groundwater Quality ◽  
Quality Indicator ◽  
Ordinary Kriging ◽  
Indicator Kriging ◽  
Disjunctive Kriging ◽  
Kriging Method ◽  
Lognormal Kriging ◽  
Groundwater Contaminants ◽  
Simple Kriging

Kriging, a geostatistical technique, has been used for many years to evaluate groundwater quality. The best estimation data for unsampled points were determined by using this method depending on measured variables for an area. The groundwater contaminants assessment worldwide was found through many kriging methods. The present paper shows a review of the most known methods of kriging that were used in estimating and mapping the groundwater quality. Indicator kriging, simple kriging, cokriging, ordinary kriging, disjunctive kriging and lognormal kriging are the most used techniques. In addition, the concept of the disjunctive kriging method was explained in this work to be easily understood.

scholarly journals Delineating reclamation zones for site-specific reclamation of saline-sodic soils in Dushak, Turkmenistan

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256355
Author(s):  
Elif Günal
Keyword(s):  
Soil Salinity ◽  
Land Development ◽  
Soil Salinization ◽  
Accurate Information ◽  
Soil Reaction ◽  
Target Area ◽  
Sodic Soils ◽  
Spatial Trend ◽  
Soil Layers ◽  
Best Management

Soil salinization is the widespread problem seriously affecting the agricultural sustainability and causing income losses in arid regions. The major objective of the study was to quantify and map the spatial variability of soil salinity and sodicity. Determining salinity and sodicity variability in different soil layers was the second objective. Finally, proposing an approach for delineating different salinity and sodicity zones was the third objective. The study was carried out in 871.1 ha farmland in Southeast of Dushak town of Ahal Province, Turkmenistan. Soil properties, including electrical conductivity (EC), soil reaction (pH), sodium adsorption ratio (SAR), calcium carbonate and particle size distribution (clay, silt and sand fractions) in 0–30, 30–60, 60–90 and 90–120 cm soil layers were recorded. The EC values in different soil layers indicated serious soil salinization problem in the study area. The mean EC values in 0–90 cm depth were high (8 dS m-1), classifying the soils as moderate to strongly saline. Spatial dependence calculated by the nugget to sill ratio indicated a strong spatial autocorrelation. The elevation was the primary factor affecting spatial variation of soil salinity in the study area. The reclamation of the field can be planned based on three distinct areas, i.e., high (≥12 dS m-1), moderate (12–8 dS m-1) and low (<8 dS m-1) EC values. The spatial trend analyses of SAR values revealed similar patterns for EC and pH; both of which gradually decreased from north to the south-west. The amount of water needed to leach down the salts from 60 cm of soil profile is between 56.4–150.0 ton ha-1 and the average leaching water was 89.8 tons ha-1. The application of leaching water based on the amount of average leaching water will result in higher or lower leaching water application to most locations and the efficiency of the reclamation efforts will be low. Similar results were recorded for sulfur, sulfuric acid and gypsum requirements to remediate sodicity. The results concluded that the best management strategy in planning land development and reclamation schemes for saline and sodic soils require accurate information about the spatial distribution of salinity and sodicity across the target area.

scholarly journals LEAKAGE OF UV-ABSORBING SOLUTES FROM SALT-AFFECTED ROOT TIPS OF PISTACHIO ROOTSTOCKS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1136e-1136
Author(s):  
G.A. Picchioni ◽  
S. Miyamoto ◽  
J.B. Storey
Keyword(s):  
Root Growth ◽  
Soil Salinity ◽  
Cellular Damage ◽  
Root Tips ◽  
Pistacia Atlantica ◽  
Solute Leakage ◽  
Soil Solutions ◽  
Saline Solutions ◽  
Made In

Excised root tips from 3-year-old pistachio rootstock (Pistacia atlantica Desf., P. terebinthus L., and P. integerrima Stewart × atlantica) were exposed to laboratory saline solutions for 24 hr. Treatments simulated the compositions of soil solutions in a previous 2-year study made in outdoor lysimeters. Leakage of UV-absorbing solutes, an indication of cellular damage, occurred with 175 mM Na/12.5 mM Ca, which was comparable to soil salinity which increased leaf Na concentrations and decreased root growth of these species Up to. five times higher leakage occurred from roots of a P. terebinthus genotype having least Na exclusion potential during the lysimeter study. Use of isotonic levels of CaCl2, mannitol, and simulated Na/Ca solutions resulted in similar damage. However, isotonic Na (-Ca) caused highest leakage overall. Correlation between long-term observations in the lysimeters and leakage occurrence-in the laboratory indicates that solute leakage tests may aid in characterizing responses of Pistacia spp. roots cocks to saline conditions.

A CRITICAL COMPARISON OF KRIGING, FRACTAL AND INDICATOR KRIGING TECHNIQUES

1993 ◽  
Vol 33 (1) ◽  
pp. 330
Author(s):  
T.A. Gray ◽  
F.X. Jian ◽  
I.J. Taggart.
Keyword(s):  
Oil Recovery ◽  
Oil Production ◽  
Indicator Kriging ◽  
Oil Fields ◽  
Critical Comparison ◽  
Synthetic Model ◽  
Geostatistical Models ◽  
Geostatistical Techniques ◽  
Recovery Performance

Geological and geostatistical characterisation of reservoir heterogeneities is becoming increasingly popular for the maximisation of oil production from existing oil fields. Many geostatistical techniques, such as kriging, fractal and indicator kriging, have become available either in published or commercial forms. There is, however, little information available and even fewer comparisons between methods to guide users in this area. This paper compares oil recovery performance based on different geostatistical models generated by kriging, fractal and indicator kriging techniques with a constructed synthetic model typical of a fluvial-deltaic sequence.

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