Soil Analysis Research Articles

Ecological Studies of Saurashtra Coast and Neighbouring Islands II. Beyt Island

The plant ecology Beyt island, a narrow crooked strip of sand rock to the east of Okhamandal point and about 3 km to the north of the mainland of Okhamandal situated 22°35' : 72°21' in the Gulf of Cutch is presented in this paper. Based on the types of situations and edaphic features the vegetation of the island has been distinguished into 3 main categories : (1) Strand, (2) Salt pans, slacks and mud formations and (3) Inland mixed scrub forest. Main features of thewvegetation and analysis of soils are described under the'above mentioned heads. The flora is a mixture of coastal and inland types. Further, the affinity of the flora with the adjacent lands of Cutch and Okhamandal to Diu coastal area has been studied. A list of the plants occurring in the island is enumerated.

Ecological Studies of Saurashtra Coast and Neighbouring Islands. V. Jafarabad to Bhavnagar Coastal Area

This paper is an ecological account of the plant communities and habitats observed in the coastal areas of Saurashtra from Jafarabad to Bhavnagar between 20°52': 21°45' and 71°25': 72°12'; ecological aspects are presented on an ecosystem basis. Plant communities grouped under ecosystems and analyses of soils are described to study soil features in relation to vegetation. A list of the coastal plants is prepared to record their distribution.

Ecological Studies of Saurashtra Coast and Neighbouring Islands: I. Diu Island

The plant ecology of Diu, an island of irregular outline, situated in 20°43' N & 71°02' E and separated from the southern extremity of the peninsula of Saurashtra by a narrow channel on western shore of India is presented in this paper. Several plant communities are grouped into three ecosystems : Rock-strand, Strand and Inland sandy plain. The community type is a sub-division of an ecosystem, that is, it is recognised by the features of both its plant cover and its habitat. Plant communities under each of the three abovementioned ecosystems are described and also analysis of rocks and soils presented in tabular form to study soil features in relation to vegetation.

Path to autonomous soil sampling and analysis by ground-based robots

Good site characterization is essential for the selection of remediation alternatives for impacted soils. The value of site characterization is critically dependent on the quality and quantity of the data collected. Current methods for characterizing impacted soils rely on expensive manual sample collection and off-site analysis. However, recent advances in terrestrial robotics and artificial intelligence offer a potentially revolutionary set of tools and methods that will help to autonomously explore natural environments, select sample locations with the highest value of information, extract samples, and analyze the data in real-time without exposing humans to potentially hazardous conditions. A fundamental challenge to realizing this potential is determining how to design an autonomous system for a given investigation with many, and often conflicting design criteria. This work presents a novel design methodology to navigate these criteria. Specifically, this methodology breaks the system into four components – sensing, sampling, mobility, and autonomy – and connects design variables to the investigation objectives and constraints. These connections are established for each component through a survey of existing technology, discussion of key technical challenges, and highlighting conditions where generality can promote multi-application deployment. An illustrative example of this design process is presented for the development and deployment of a robotic platform characterizing salt-impacted oil & gas reserve pits. After calibration, the relationship between the in situ robot chloride measurements and laboratory-based chloride measurements had a good linear relationship (R2-value = 0.861) and statistical significance (p-value = 0.003).

X-ray Fluorescence Core Scanning for High-Resolution Geochemical Characterisation of Soils

X-ray fluorescence (XRF) core scanners are commonly used for fine-scale geochemical analysis in sediment studies, but data are semi-quantitative and require calibration to convert geochemical element counts to concentrations. Application of XRF core scanning in soil science remains largely untapped. This study employed an ITRAX core scanner to scan grassland soil cores and developed a novel calibration method based on a chemometric approach to characterise soil geochemistry. As soil samples are collected based on depth sampling, this study investigated whether higher resolution element concentrations could be inferred from lower resolution reference samples and if regression models from multiple cores could apply to a new core at the same resolution. Reference concentrations were obtained for all cores at 10 cm intervals, with validation conducted at 1 cm for a single core. Two calibration curve types were proposed: one based on the single core’s 10 cm data to validate references at 1 cm intervals; and another using all cores, with each core serving as a test item after exclusion from the training set. Various preprocessing measures and feature selection techniques were tested. Results showed successful calibration for elements Ca, P, Zn, Sr, and S, with high R2 values of 0.94, 0.93, 0.93, 0.92 and 0.91, respectively. The study presents a novel method for calibrating XRF core scanning element counts, demonstrating its potential for high-resolution soil analysis.

Crop Monitoring System Using IOT

Currently, the low agricultural output is causing farmers to suffer. Low crop growth is primarily caused by knowledge of soil fertility and crop selection, even though proper crop selection is the primary booster key for enhancing agricultural yield by doing soil analysis and taking metrological elements into consideration. Farmers with limited experience in conventional farming are finding it difficult to make wise crop selection choices in the current environment. The low soil fertility is caused by the same crop being chosen for each seasonal cycle. The goal of this research is to use IoT devices to create an accurate and efficient system. Compared to the outdated manual laboratory testing procedures, which are subject to human errors, such a system is predictable. A crop's proper selection is mostly important in the agricultural field. As a contribution, we offer Smart Crop Selection (SCS), an IOT-based approach that is based on soil and metrological factor data. These variables include soil moisture content, temperature, and precipitation. Because these issues are not given as much care as they should, existing IoT-based systems are less efficient than our proposed model. Real-time sensory data is transmitted to Firebase cloud for analysis in the suggested model

Lead Speciation, Bioaccessibility, and Sources for a Contaminated Subset of House Dust and Soils Collected from Similar United States Residences.

Residential lead (Pb) exposure is of critical concern to families globally as Pb promotes severe neurological effects in children, especially those less than 5 years old, and no blood lead level is deemed safe by the US Center for Disease Control. House dust and soils are commonly thought to be important sources of Pb exposure. Probing the relationship between house dust and soil Pb is critical to understanding residential exposure, as Pb bioavailability is highly influenced by Pb sources and/or species. We investigated paired house dust and soil collected from homes built before 1978 to determine Pb speciation, source, and bioaccessibility with the primary goal of assessing chemical factors driving Pb exposure in residential media. House dust was predominately found to contain (hydro)cerussite (i.e., Pb (hydroxy)carbonate) phases commonly used in Pb-based paint that, in-turn, promoted elevated bioaccessibility (>60%). Pb X-ray absorption spectroscopy, μ-XRF mapping, and Pb isotope ratio analysis for house dust and soils support house dust Pb as chemically unique compared to exterior soils, although paint Pb is expected to be a major source for both. Soil pedogenesis and increased protection from environmental conditions (e.g., weathering) in households is expected to greatly impact Pb phase differences between house dust and soils, subsequently dictating differences in Pb exposure.

Utilization of graphene as an alternative sustainable amendment in improving soil health through accelerated decomposition of oil palm mulch and enhanced nutrient availability

Graphene has unique properties for improving soil health properties such as nutrient availability, soil physical and chemical properties, and controlled release of essential elements. This research aimed at determining the impact of graphene amendment on the decomposition of oil palm frond mulching and on soil health status. The study was conducted using a factorial experiment in completely randomized design with two main factors: (i) covering conditions: cover with plastic sheet and no cover, and (ii) graphene application that included T1 (control): oil palm frond mulching (OFM), T2: OFM + graphene (G), T3: OFM + G + chemical fertilizer, and T4: OFM + G + goat manure. The results indicated that there were significant differences among graphene applications, between cover conditions, and in interactions between graphene applications and cover conditions for all soil characteristics in the most observed month. In the third month of soil analysis, the treatment of graphene applications showed higher electrical conductivity (T2: 151.7 ± 6.8 µS cm−1), available phosphorus (T3: 9.0 ± 6.7 mg kg−1), exchangeable potassium (T2: 67.1 ± 24.9 mg kg−1), and exchangeable calcium (T3: 95.4 ± 5.1 mg kg−1), compared to control. The cover condition showed suitable soil pH (5.0 ± 0.2), higher soil available phosphorus (7.1 ± 5.0 mg kg−1), and exchangeable calcium (599.1 ± 235.2 mg kg−1), but the no-cover condition presented higher soil organic matter (0.7% ± 0.2%), exchangeable potassium (60.3 ± 19.1 mg kg−1), and exchangeable magnesium (96.7 ± 11.4 mg kg−1). Correlation results indicated that most soil characteristics were correlated under graphene applications. Principal component analysis showed that the treatments of graphene application dominated most soil characteristics. The results suggest that graphene has potential for improving soil health properties and can be applied as an alternative sustainable amendment to accelerate the decomposition of oil palm frond mulch and enhance nutrient availability for oil palm. In addition, the authors suggest that further investigations should consider more soil health parameters in long-term field studies for a better understanding and to provide recommendations to farmers.

Artisanal and Small-Scale Gold Mining Impact on Soil and Agriculture: Evidence from Upper Denkyira East Municipality, Ghana

The gold mining industry in Ghana has made a substantial contribution to the country's economic growth by generating diverse employment opportunities, both directly and indirectly, in mining communities. This has the potential to mitigate poverty and improve the quality of life for individuals and households in rural areas, where climate change is having a disproportionate impact on small-scale farmers. Nevertheless, it is crucial to recognize that this sector has also resulted in detrimental environmental impacts. A total 150 key informants in Upper Denkyira East Municipality, comprising representatives from the Environmental Protection Agency, the Forestry Commission, the Mineral Commission, and other stakeholders, were interviewed using standardize questionnaire to ascertain the impact of mining on the soil, agriculture and the environment. The study also employed inductively coupled plasma to assess the concentration of heavy metals in soils at a small-scale mining site. The soil analyses indicated high concentrations of heavy metals, such as mercury, arsenic, nickel, zinc, and iron. The Weighted Average Index, which was used to assess the impact of mining, revealed that communities face challenges such as deforestation, low crop yields, water pollution, land tenure issues, and a high cost of living. The study's analyses of measures to address small scale mining challenges revealed that alternative livelihood, law enforcement, training and support, and access to mining concessions were perceived as suitable for addressing artisanal and small scale mining. The study concluded that stricter mining regulations, promoting sustainable mining practices, and providing comprehensive training to miners on environmental protection and land reclamation can help mitigate the negative impacts of artisanal and small-scale mining. Additionally, supporting alternative means of livelihood for mining communities, such as agriculture or eco-tourism, can reduce reliance on mining and promote sustainable development.

Applications of multi-parameter sensing in pharmaceutical, agriculture and mineral industries using THz spectroscopy and Low-Wavenumber Raman spectroscopy

Multi-parameter sensing using non-destructive optical spectroscopic techniques, specifically Terahertz spectroscopy and low-wavenumber Raman spectroscopy (also known as THz-Raman spectroscopy), has significantly reshaped the landscape of analytical methodologies in various industries. This comprehensive review article elucidates the transformative impact of these advanced spectroscopic methods within the fields of pharmaceutical, agriculture, and mineral industry. As technology continues to evolve, the ability to concurrently analyse multiple parameters at the molecular level has become a cornerstone for precision and efficiency in these critical sectors. In the pharmaceutical industry, THz spectroscopy has emerged as a key tool in ensuring the quality and stability of drug formulations, while low-wavenumber Raman spectroscopy complements by offering insights into chemical structure as well as composition. The agricultural sector benefits from the capabilities of these spectroscopic techniques in optimizing crop management, soil analysis, and resource utilization. Simultaneously, the mineral industry leverages THz and low-wavenumber Raman spectroscopy for accurate mineral identification, aiding in exploration, extraction, and processing. Through this review, we aim to provide a nuanced understanding of how multi-parameter sensing through THz and low-wavenumber Raman spectroscopy is driving innovation, enhancing quality control, and fostering sustainable practices across diverse industrial landscapes.

GEOLOGY AND THE STUDY OF HEAVY METAL IMPACTS ON ENVIRONMENTAL QUALITY ASSESSMENT USING ARCGIS FOR INTERPRETATION DISTRIBUTION

The Boto area, Jatiroto District, Wonogiri Regency, Central Java, Indonesia, is a traditional gold mining site with inadequate waste management practices, particularly mercury usage. This study aims to assess mercury contamination and evaluate phytoremediation potential in the area. Geological mapping, petrographic analysis, fossil analysis, stereographic analysis, soil Hg measurement, soil and water chemistry analysis, and XRF analysis were conducted to characterize the geology, geomorphology, and heavy metal distribution. The study area is divided into four geomorphological units: Intrusive Hill Unit (V1), Homoklin Hill Unit (S1), Karst Hill Unit (K1), and Alluvial Plain Unit (F1). Stratigraphically, the area consists of the Nglanggeran Breccia Unit interbedded with early Miocene lava, the early Miocene andesite Intrusion Unit with a terrestrial depositional environment, the Wonosari Limestone Unit of Middle-Late Miocene age, and the Holocene Alluvial Deposit Unit. Geological structures include left-lateral normal faults trending relatively north-south (Sesar Boto), left-lateral normal faults trending southeast-northwest (Sesar Brenggolo), and right-lateral downthrown faults trending southeast-northwest (Sesar Mesu). Fractures and veins are also present. Mercury (Hg), manganese (Mn), arsenic (As), and lead (Pb) distribution mapping was conducted. The contaminated zone falls into TCLP-A, and waste management falls into category 1, located in Boto Village, which is a gold mining and processing area. Phytoremediation is proposed as a remediation strategy. Keywords: gold mining, heavy metals, XRF, phytoremediation, distribution

Study on the Influence of Canopy Density on Cycling of Soil Available N in Different Landform of Loess Plateau in China

In this paper, a total of 330 soil samples with 0-100cm soil depth of 66 planted square forest (10*10m) with different canopy density in the Loess Plateau were selected for the determination and analysis of soil N content in different soil layers, and the effects of different canopy density on soil N cycle under different topographic factors of planted forest were studied. The results showed as follows: (1) the migration mechanism of different N forms to the root surface was different, the migration of nitrate nitrogen to the root surface mainly depended on mass flow, there was enrichment phenomenon near the root, ammonium nitrogen mainly through diffusion, resulting in deficiency and loss in the near rhizosphere, and the leaching loss of nitrate nitrogen was affected by soil water and root growth. (2) The thickness, composition and decomposition rate of litter were different due to different canopy density, which affected the content of ammonium nitrogen and nitrate nitrogen in forest soil. (3) Although the change of different regions in this region was spatially different, keeping the stand cover in the middle and high range of 0.75-0.8 can be conducive to maintaining the balance between the consumption of soil nutrients by the stand and the supplement of nutrient consumption, which can also be conducive to the sustainable recovery and growth of the stand in this region.

Analysis of r - Adaptive coupling adaptive time integration strategy in FEM of seismic liquefaction

In seismic finite element analysis of saturated soils, the challenges primarily reside in liquefaction and the large deformation of soil induced by strong earthquakes. Traditional updated Lagrangian methods may result in severe mesh distortion after updating the spatial configuration of nodes. To address this issue, this study develops an r - adaptive approach based on a solid - fluid coupling finite element method (FEM) platform to mitigate mesh distortion problems. This technique optimizes mesh nodes without altering the overall topology, thereby maintaining mesh integrity. However, enhancing mesh accuracy comes at the expense of increased computational costs. To alleviate high computational expenses, this study couples two types of adaptive time stepping techniques, based on mixed error and displacement history curvature, with mesh adaptation. Through verification on two typical dynamic liquefaction models of saturated soil on embankment and subway station, this technique effectively balances the relationship between computational accuracy and costs.

Yield Maximization of Rice (Oryza sativa) through Integrated Nutrient Management

This experiment was conducted on a permanent layout at the west byde of BRRI farm, Gazipur during T. Aman 2019 to Boro 2021-22 to find out the suitable management practices for yield maximization of rice and soil health. Seven treatments in Randomized Complete Block (RCB) Design with three replications were imposed and each treatment was assigned in 5m × 4m sized plot. The treatments combinations were T1= Absolute Control (No nutrient supply), T2 = BRRI dose N-P-K-S@83-17-53-12 kg ha-1 in T. Aman and 138-21-75-21 kg ha-1 in Boro season, T3= Soil Test Based (STB) Fertilizer Dose N-P-K-S @ 67-10-40-10 kg ha-1 in T. Aman and 134-16-75-10 kg ha-1 in Boro, T4 = STB dose + 1 t ha-1 Cowdung, T5 = STB dose + 1 t ha-1 Poultry manure, T6 = STB dose + 1 t ha-1 Vermicompost and T7 = STB dose + 0.33 t ha-1 CD + 0.33 t ha-1 PM + 0.33 t ha-1 VC. Thirty-days old seedling of BRRI dhan87 in T. Aman and fourty-two days old seedling of BRRI dhan89 in Boro season were transplanted at 20 cm × 20 cm spacing in both seasons. All manures, soil and plant samples analysis were done by the help of soil Science Division BRRI, Gazipur. Initial soil (0-15 cm depth) properties were: soil texture, clay loam; pH, 6.94; organic Carbon, 1.59%; Nitrogen, 0.18%; Phosphorus, 21.88 ppm and Potassium, 0.19meq/100g soil. Thirty days old seedling of BRRI dhan87 in T. Aman and 42 days old seedling of BRRI dhan89 in Boro season were transplanted at 20cm x 20cm spacing. Grain yield, tiller number, panicle number, plant height and grain number were significantly affected by the different integrated nutrient management during both T. Aman and Boro season. Grain yield, tiller number, panicle number, plant height and grain number were significantly affected by the different nutrient management in both T. Aman and Boro season. Poultry manure related treatments and BRRI recommended dose performed better than the others in all the parameter except 1000-grain weight. On the other hand, Absolute Control (No nutrient supply) produced the lowest result. Every parameter, Poultry manure treatments have been performed the best. STB dose with one t ha-1 poultry manure is better for maximization of rice yield.

Prevalence of Chronic Kidney Disease and its Association with Pesticide Exposure in Bargarh District, Odisha, India

Background: Bargarh, a district in Odisha, is known for intense agricultural activities because of uninterrupted irrigation from the Hirakud reservoir. The number of chronic kidney disease (CKD) cases in the district is increasing rapidly. The present study assesses the prevalence of CKD and CKDu (of unknown etiology) in the district and its association with pesticide application. Materials and Methods: A door-to-door survey was conducted to find out the CKD hotspots in the different blocks of the district with the help of primary and community health centers. The prevalence of CKD in the identified hotspot villages was assessed using a random clustered sampling method along with the collection of data related to age, sex, occupation and source of drinking water. Soil and water samples collected from identified hotspot and nonhotspot villages were analyzed to assess the presence of nephrotoxic pesticide residues. Results: A total of 16 villages were identified with high CKD prevalence rates and designated as hotspot villages. Data indicate that about 21% of males under ≥ 40 years age group were found to be suffering from CKD. Cases of CKDu (85%) were more prominent in these hotspot villages. Analysis of soil and water samples demonstrated the presence of seven different nephrotoxic pesticides above the maximum residues levels (MRLs) in hotspot villages compared to nonhotspot villages. Conclusion: The presence of nephrotoxic pesticides above MRLs in the hotspot villages indicates their possible association with the onset and progression of CKD among the exposed population. Further research is needed to establish their causative association with CKDu in the study region.

An updated checklist of serpentinophytes for research and conservation in ultramafic ecosystems on the southern Iberian Peninsula (Spain)

AbstractAlthough checklists are essential tools for managing and conserving ultramafic ecosystems, no updated checklist currently exists for ultramafic ecosystems on the southern Iberian Peninsula. Thus, the objectives of our study were (1) to create an updated checklist of serpentinophytes on southern Iberian Peninsula, (2) to determine whether the distribution of serpentinophytes is associated with certain specific types of ultramafic rocks, and (3) to calculate the abundance and richness of serpentinophytes per outcrop to guide conservation efforts. Following a methodology involving field work and searches of bibliographies and herbaria we produced an updated checklist containing 28 serpentinophytes (i.e., 23 obligates, one preferential taxon, one sub‐serpentinophyte, and three regional serpentinophytes). The serpentinophytes showed different petrological affinity, where harzburgite–lherzolite and harzburgite–pyroxenite–dunite exhibited higher occupancy, possibly due to their mineralogical and chemical composition (e.g., containing heavy metals) and/or the larger surface area of those outcrops. We also observed that the occupancy of 21 species was higher in different petrographic entities, the reasons for which could be elucidated by future soil analyses. The highest richness of serpentinophytes was found in the main outcrop of Bermeja, followed by smaller outcrops of Alpujata, Aguas, and Guadalhorce Valley. Although the richness of Aguas resembled that of Alpujata, a notable difference emerged in some of its areas owing to bioclimatic and biogeographic isolation. Given the exclusive presence of serpentinophyte flora on the southern Iberian Peninsula, all southern Iberian outcrops should receive some form of conservation as protected natural spaces.

Accurate method based on data filtering for quantitative multi-element analysis of soils using CF-LIBS

To obtain more stable spectral data for accurate quantitative analysis of multi-element, especially for the large-area in-situ elements detection of soils, we propose a method for a multi-element quantitative analysis of soils using calibration-free laser-induced breakdown spectroscopy (CF-LIBS) based on data filtering. In this study, we analyze a standard soil sample doped with two heavy metal elements, Cu and Cd, with a specific focus on the line of Cu I 324.75 nm for filtering the experimental data of multiple sample sets. Pre- and post- data filtering, the relative standard deviation for Cu decreased from 30% to 10%, The limits of detection (LOD) values for Cu and Cd decreased by 5% and 4%, respectively. Through CF-LIBS, a quantitative analysis was conducted to determine the relative content of elements in soils. Using Cu as a reference, the concentration of Cd was accurately calculated. The results show that post- data filtering, the average relative error of the Cd decreases from 11% to 5%, indicating the effectiveness of data filtering in improving the accuracy of quantitative analysis. Moreover, the content of Si, Fe and other elements can be accurately calculated using this method. To further correct the calculation, the results for Cd was used to provide a more precise calculation. This approach is of great importance for the large-area in-situ heavy metals and trace elements detection in soil, as well as for rapid and accurate quantitative analysis.

How healthy are horticultural plants cultivated in urban gardens in polluted cities? The case of Mexico City

Soil-to-plant metal(loid) accumulation has been highly evaluated recently due to its significant impact on human health. This study reports the concentrations of 15 metal(oid)s in four vegetables (tomato, onion, chili, and lettuce) cultivated in a greenhouse and three shade houses (two roofs of buildings and one in the UNAM Botanical Garden) in four locations in the metropolitan area of Mexico City. In this experiment, the contribution of metals and metalloids due to atmospheric deposition and irrigation may be negligible. Hence, the concentration of metals depends only on transfer from the soil. Soil analysis indicates that only vanadium in one location (a rooftop garden in the municipality of Venustiano Carranza) exceeds the permissible limits according to Mexican regulations. Lettuce shows the highest concentrations and transfer factors for most metals compared to the other vegetables studied. Transfer factors were exceptionally high for Cd (lettuce) and Hg (tomato), presenting values above 1. Concentrations of As, Cd, Hg, and Pb were compared with limit values recommended by different international agencies for vegetables. It was observed that, except for As, these values are exceeded in various vegetables harvested in this study. This information must be corroborated with more detailed studies evaluating the chemical species in which those metal(oid)s are present and identify the physical and chemical parameters of the soil that may have interfered with the soil-plant transfer factor.

Precision Irrigation Soil Moisture Mapper: A Thermal Inertia Approach to Estimating Volumetric Soil Water Content Using Unmanned Aerial Vehicles and Multispectral Imagery

To address the issue of estimating soil moisture at a hyper-resolution scale, a methodology referred to as Precision Irrigation Soil Moisture Mapper (PrISMM), that includes three key components, is developed: high-resolution remotely sensed optical and thermal data, surface energy balance modeling, and site-specific soil analysis. An Unmanned Aerial Vehicle/System (UAV or UAS) collects high-resolution multispectral imagery in the Dallas–Fort Worth metropolitan study area. Orthomosaics are converted to thermal inertia estimates in a spatially distributed format using the remotely sensed data combined with a set of surface energy balance modeling equations. Using thermal and physical properties of soil gained from site-specific soil analysis, thermal inertia estimates were further converted from thermal inertia to daily volumetric soil water content (VSWC) with a horizonal resolution of 8.6 cm. A ground truthing dataset of measured VSWC values taken from a Time Domain Reflectometer was compared with model results, producing a reasonable correlation with an average coefficient of determination of (R2) = 0.79, an average root mean square error (RMSE) = 0.0408, and mean absolute error (MAE) = 0.0308. This study highlights a practical approach of estimating VSWC for irrigation purposes while providing superior spatio-temporal coverage over in situ methods. The authors envision that PrISMM can be implemented in water usage management by relating VSWC with weather forecasts and evapotranspiration rates to develop time-based spatially distributed irrigation management plans.

Assessment of agricultural land salinization via soil analysis and remote sensing data: Case study in Pavlodar region, Kazakhstan

Assessment of agricultural land salinization via soil analysis and remote sensing data: Case study in Pavlodar region, Kazakhstan