Spatial Variability Maps Research Articles

Chlorine Decay Simulation in Water Distribution System Using EPANET

Chlorine is used as a disinfectant in the water treatment process so that treated water is delivered safely to consumers. However, chlorine concentration decays when water flows from the treatment plant to the supply point, due to the reaction with natural organic matter and the inner surface of the pipe. Low chlorine concentration may encourage bacteria re-growth, while high chlorine concentration can result in the formation of harmful chemical components. Therefore, this study aims to simulate the complex process of chlorine decay using EPANET. This exercise enables the determination the chlorine concentration dosage required to maintain the desired requirement given by the World Health Organization (WHO) and the Ministry of Health, Malaysia (MOH). A successful model with an extended period of simulations of 72 hours enable the mapping of spatial and temporal variations of flow and residue chlorine concentrations at all links and nodes. Constant chlorine dosage of 3.96 mg/l at node R1 has successfully satisfy the requirement given by WHO and MOH. The residue chlorine concentrations at the nodes and links in the water distribution system also depends on the water usage at node 5, the size of service reservoir and service tank and distance from the reservoir.

Comparison GIS-Based interpolation methods for mapping groundwater quality in the state of Qatar

Groundwater (GW) quality deterioration is one of the main water security issues in Qatar. GW in Qatar is over-exploited for agriculture activities that caused saltwater intrusion in the coastal areas and some inland GW. The selection of an appropriate interpolation method is crucial for producing a reliable map of spatial variability in environmental research and the decision-making process. In this study, 41 GW samples were used to produce interpolated maps and reveal the spatial variability of GW parameters namely: pH, electrical conductivity (EC), total dissolved solids (TDS), sodium adsorption ratio (SAR), major cations, and anions, and some trace elements, using spatial interpolated methods in geostatistical tool (ArcGIS Software). Multiple mapping methods were used to compare the current results with the national and international guidelines to give a relevant decision. Three different interpolated methods, namely inverse distance weighted interpolation (IDW), radial basis functions (RBFs), and simple Kriging (SK) were used to produce interpolated maps. Cross-validation was applied to assess the best-fit interpolation method. The result shows that the SK model was the optimum interpolated method for the most of the variable data. While the RBFs model was the best interpolation method for selenium and boron data. The IDW model was the best-interpolated method for sodium, TDS, SAR, and potassium data. The IDW and RBFs methods produced interpolation maps that help visualizing the location of GW within and above the guidelines. The analysis of spatial variability in the study area revealed high levels of TDS, EC, SAR, and some cations and anions in the coastal and south Qatar. While the spatial variability for nitrate and boron suggested the influence of human activities. A thorough understanding of the status of GW quality in Qatar is a significant tool for the GW management and decision-makers.

Entropy-weighted water quality index (EWQI) modeling of groundwater quality and spatial mapping in Uppar Odai Sub-Basin, South India

Groundwater is the primary source of water supply in Uppar Odai Sub-basin in the Amaravati River basin in South India. In this crystalline aquifer system, groundwater occurs in joints fissures, fractures at shallow depth in the partially weathered rocks. An integrated approach of hydrochemical analysis of 32 samples with numerical indexing Entropy-weighted water quality index(EWQI) model was proposed for the study area. General hydrochemical data showed that the Na–Cl and Ca–Mg–Cl–SO4 types dominated, with most of the samples are alkaline nature. More than 50% of the samples exceeded the permissible limit of TDS, and a high concentration of Cl and NO3 showed the influence of anthropogenic influences, such as industrial effluents and agricultural fertilizers. Groundwater chemistry was found to be varying along the groundwater flow paths. Geogenic contaminant F¯ was exceeding the WHO permissible limit of 1.5 mg/L. Entropy-weighted Water Quality Index (EWQI) model showed that 53% of the samples were medium, and 22% were of poor quality. Na–Cl and mixed Ca–Mg–Cl types of water were reported with high EWQI values. A high correlation for EWQI with TDS, TH, Mg, Cl, SO4, and NO3 is an indication of the human activities on the groundwater quality. GIS-based spatial variation maps of water quality parameters and EWQI specify that northern, northwestern, and central regions are poor water quality. In those regions where water quality has deteriorated, proper treatment of water is suggested before consumption to avoid health risks.

Mapping of spatial variations in Sr isotope signatures (87Sr/86Sr) in Poland — Implications of anthropogenic Sr contamination for archaeological provenance and migration research

This study presents first isoscape maps of strontium isotope signatures and their spatial variation in Poland, based on ~900 samples of rocks, sediments, surface water, and flora. This dataset is supplemented by 87Sr/86Sr ratios predicted for several carbonate rock units. High, radiogenic Sr isotope ratios (>0.72), related to the Pleistocene glacial deposits, are omnipresent throughout the country and are also found in the Sudetes and the Holy Cross Mountains, where igneous and clastic Palaeozoic rocks are widely exposed. The lowest Sr signatures (<0.71) occur predominantly in the Silesian-Małopolska and Lublin uplands and are related to exposures of Palaeozoic, Mesozoic, and Neogene carbonate rocks. The large variation of 87Sr/86Sr ratios in the environment across the country is chiefly driven by the diversity in the geological substrate, and locally, it is also influenced by anthropogenic contamination. Strontium isoscapes for the geological substrate and surface waters differ from each other, in terms of the range of 87Sr/86Sr values and their distributional pattern. The differences result primarily from mixing processes in the geosphere (weathering), hydrosphere, and biosphere that control Sr inputs from various natural sources present in the environment. On the other side, they are also created by anthropogenic contamination of surface water and presumably of soils. This situation has important implications for future archaeological provenance and migration studies, as isoscapes for surface water and vegetation cannot be directly used to estimate the local 87Sr/86Sr baselines for past human populations. Therefore, caution is required when modern Sr data of surface water and plants are used in archaeological research. 87Sr/86Sr values of the geological substrate, which may be affected by anthropogenic contamination to a lesser extent than water, soil, and vegetation, are favoured for the baseline estimation for historical times.

VARIABILIDADE ESPACIAL EM SISTEMA AGROFLORESTAL SILVIBANANEIRO, NO LITORAL DO RIO GRANDE DO SUL, COM gvSIG

Os sistemas agroflorestais (SAF) são alternativas importantes para gerar renda com agricultura sustentável, a exemplo dos SAF no Litoral Norte do Rio Grande do Sul. Porém, ainda são poucos os trabalhos que utilizam a abordagem da agricultura ou floresta de precisão, com uso da espacialização de atributos da vegetação dos SAF, sendo este o objetivo desta pesquisa. Foi realizado um inventário num SAF silvibananeiro localizado em Três Cachoeiras, sendo instaladas 33 unidades amostrais (ua) para mensuração dos indivíduos arbóreos com CAP &gt;15 cm. As ua foram georreferenciadas, localizando os parâmetros fitossociológicos, que foram interpolados por ponderação pelo inverso da distância (IDW) no gvSIG, que juntamente com os limites do SAF deram origem a mapas de variabilidade espacial. A principal espécie observada foi palmito juçara (Euterpe edulis Mart. - Família Arecaceae) com 75 indivíduos amostrados, com dominância, frequência e densidade relativas de 17, 22,2 e 37%, respectivamente, e importância de importância de 76,2 %. As variáveis que apresentaram variabilidade espacial evidente foram número de espécies, diversidade máxima, os índice de diversidade, dominância e equabilidade, número de palmiteiros e de cachos de banana verde. Conclui-se que os atributos do SAF silvibananeiro possuem variabilidade espacial e que a metodologia utilizada foi adequada.

Compatibility of Electromagnetic (EM) Method and Geospatial Analysis for Identifying the Vulnerable Building Zonation in Coastline Area of Ado-Odo Ota, Ogun State, Nigeria

Collapsing of building incidents have been reported all over the world and seems to be commonespecially in sedimentary terrain of the coastal plain sand of Ado-Odo Ota which has the same subsurface features as the Lagos that experience regular building collapse. This building collapse is attributed to several causes. The reasons that have been identified, have added little or no impact on reducing this environmental disaster. This study presents the strength of emerging and existing geophysical tools for near-surface structural studies. The aim is to reveal the recent technical development on improving field surveys to minimize building collapse. Data acquisition using electromagnetic (EM) methods which are known for fast mapping of near-surface spatial variation as well as obtaining the subsurface vertical variation in electrical conductivity was adopted. The acquired spatial and attribute data was introduced in a GIS environment with different thematic vectors/layers created by digitizing the satellite image of the study area. The GIS digitizing was to geographically trace the acquired data with accurate coordinates from the obtained EM field data with the thematic layer representing the features such as weak zone and competence zones that can hold buildings. A transverse was taken in a strategic positions considering the regional features with 10 m spacing to cover the marked stations. It revealed the layer depths range from 0.37 to 1.64 m with the much competence layer found to be about 1.64 mbeyond which may be the thick clay Ilaro formation that underlies the recent formation. The weathered shear zone at the depth of 0.37 m may be the recent lithoral deposits which is geotechnically and geologicallyunstable and proximity to active faults of ruptured geomorphology of the building zonation.

The Relationship between Soil Electrical Parameters and Compaction of Sandy Clay Loam Soil

Soil spatial variability mapping allows the delimitation of the number of soil samples investigated to describe agricultural areas; it is crucial in precision agriculture. Electrical soil parameters are promising factors for the delimitation of management zones. One of the soil parameters that affects yield is soil compaction. The objective of this work was to indicate electrical parameters useful for the delimitation of management zones connected with soil compaction. For this purpose, the measurement of apparent soil electrical conductivity and magnetic susceptibility was conducted at two depths: 0.5 and 1 m. Soil compaction was measured for a soil layer at 0–0.5 m. Relationships between electrical soil parameters and soil compaction were modelled with the use of two types of neural networks—multilayer perceptron (MLP) and radial basis function (RBF). Better prediction quality was observed for RBF models. It can be stated that in the mathematical model, the apparent soil electrical conductivity affects soil compaction significantly more than magnetic susceptibility. However, magnetic susceptibility gives additional information about soil properties, and therefore, both electrical parameters should be used simultaneously for the delimitation of management zones.

Mapping spatial and temporal variation of seafloor organic matter Δ14C and δ13C in the Northern Gulf of Mexico following the Deepwater Horizon Oil Spill

Following the Deepwater Horizon oil spill of 2010, large amounts of biodegraded oil (petrocarbon) sank to the seafloor. Our objectives were to 1) determine post-spill isotopic values as the sediments approached a new baseline and 2) track the recovery of affected sediments. Sediment organic carbon δ13C and Δ14C reached a post-spill baseline averaging −21.2 ± 0.9‰ (n = 129) and −220 ± 66‰ (n = 95). Spatial variations in seafloor organic carbon baseline isotopic values, 13C and 14C, were influenced by river discharge and hydrocarbon seepage, respectively. Inverse Distance Weighting of surface sediment Δ14C values away from seep sites showed a 50% decrease in the total mass of petrocarbon, from 2010 to 2014. We estimated a rate of loss of −2 × 109 g of petrocarbon-C/year, 2–11% of the degradation rates in surface slicks. Despite the observed recovery in sediments, lingering residual material in the surface sediments was evident seven years following the blowout.

Seasonal variation in groundwater quality and beneficial use for drinking, irrigation, and industrial purposes from Deccan Basaltic Region, Western India.

Sustainable management of groundwater resources requires detailed basin-wide water assessments. Semi-urbanized areas surrounding metropolitan cities in the western part of India were assessed for their suitability for domestic, irrigation, and industrial purposes. These study areas reflect rapid urban growth with residential complexes, combined with agricultural, horticultural, and industrial uses. Therefore, 68 representative groundwater samples were collected during the pre-monsoon (PRM) and post-monsoon (POM) seasons of 2015 and analyzed for major ions. According to the World Health Organization (WHO) drinking standards, parameters like EC, TDS, TH, HCO3, Ca, and Mg were found to exceed the desirable maximum limits, and the B and F content exceeded the permissible limits. The drinking suitability was studied using the modified water quality index (MWQI). The irrigation suitability was assessed using indices such as sodium adsorption ratio (SAR), percent sodium (%Na), and permeability index (PI). The industrial suitability was evaluated based on Langelier saturation index (LSI), saturation index (SI), Ryznar stability index (RSI), etc. MWQI results corroborate that 52.94 and 70% samples fall in no pollution category, and 47% and 30% samples were identified to be in the moderate category of pollution in the PRM season and POM season, respectively. The spatial variation maps of LSI, SI, RSI, Puckorius scaling index (PSI) and Larson-Skold index (LaI) show that the majority of the samples in the PRM season have low to insignificant scaling and corrosive potentials as compared to POM samples. The study results provide reliable information for water reserve managers to prepare the sustainable and more accurate basin management plans.

Indexing soil properties through constructing minimum datasets for soil quality assessment of surface and profile soils of intermontane valley (Barak, North East India)

Soil quality (SQ) assessment considering surface and profile soils holds great significance in sustainable soil health management. We assessed the effect of land-use systems (agriculture, forest and plantation) on SQ using three SQ indices (SQI) models namely additive (SQIa), weighted additive (SQIw) and nemoro (SQIn) from total (TDS) and minimum (MDS) datasets in the intermontane valley soils of North East India (Barak Valley). Surface samples were taken from 13 to 24 cm depth and profile samples were taken up to 102–167 cm depth from 67 profiles selected by multi-layer thematic overlay analysis of agro-physical parameters with Survey of India (SOI) topo-sheets at 1:50 K scale as base map. The estimated SQIs averaged over models and land-uses were nearly two-fold higher for surface (0.751 ± 0.03) and profile (0.722 ± 0.02) soils from TDS than the MDS (surface: 0.398 ± 0.09; profile: 0.333 ± 0.06) approach. The SQIn model underestimated the SQI values by 28–35% less than SQIa and SQIw for both datasets. The effect of land-uses on SQIs values was mostly non-significant (p > 0.05) for both surface and profile soils. We mapped (at 1: 50 K scale) spatial variability in SQ grades as poor, medium, good and very good in quality and validated by error matrix and Kappa analysis against independent variable (NDVI map derived from Landsat 8). The SQ maps developed from TDS were superior to MDS in Kappa agreement. Among the models, SQIw followed by SQIa from TDS had better Kappa agreement in representing spatial distribution of SQ across soil depth and land-use. We propose the SQIw model as a better option to evaluate soil quality of surface and profile soils with a satisfactory level of accuracy and reliability since it is independent of qualitative assumptions and superior in Kappa agreement for spatial variability mapping. The information generated can be harnessed for managing soil health in intermontane valleys and other such similar agro-ecological regions.

Spatial behavior of the Dar-Zarrouk parameters for exploration and differentiation of water bodies aquifers in parts of Konkan coast of Maharashtra, India

Demarcation of aquifer boundaries and hydro-geologic characterization can help in proper management and conservation of groundwater resources of a coastal region. The objective of the present study is to identify and delineate the groundwater-bearing zones and protection of freshwater aquifers from saltwater ingress in the northern parts of Sindhudurg district, western Maharashtra, India. A total of 86 vertical electrical soundings (VES) were carried out by Schlumberger electrode arrangement to infer the sub-surface lithology around Kankavali, Vijaydurg, and Malvan. The Dar-Zarrouk parameters were computed to generate the spatial variation maps of transverse resistance (T), longitudinal conductance (S), transverse resistivity (ρt), and longitudinal resistivity (ρl), to decipher the resistivity contrast of fresh water and salt water-bearing formations. The results demonstrate that these parameters provide a better resolution in delineating the seawater intrusion in coastal aquifers. The overburden aquifer protective capacity computed from the longitudinal conductance suggests that 59% of the area has poor aquifer protection, while 23% has weak, 11% has moderate and 7% falls in good protective capacity rating. This parameter reveals the infiltration of contaminants and the health of the aquifer. The electrical anisotropy (λ) value ranges from 0.9 to 5.1, suggesting an increase from SW to NE and also from SE to NW. The fracture porosity (φf) ranges from 10−6 to 0.65, which corroborates with the high and low λ values, reflecting that fracturing is due to anisotropy and significant reserves of groundwater could be exploited in this coastal region.

Particulate Pollution in Korhogo and Abidjan (Cote d’Ivoire) during the Dry Season

ABSTRACT Particulate pollution in West African cities seriously impacts public human health. Assessing the levels of pollution to which populations are exposed is problematic, as to date very few countries in Africa have an air quality monitoring network in place. However, given the specific anthropogenic sources present in West African countries and the increase in their projected emissions in the coming years if no regulations are put in place, solutions must be found. This study evaluates with a simple existing methodology particulate air pollution in two West African cities (Korhogo and Abidjan in Cote d'Ivoire) which have different population practices and local meteorology. From two measurement campaigns at about ten sites during the dry season and using the inverse distance-weighted interpolation method, maps of spatial variation in PM10 and PM2.5 concentrations are obtained at the scale of each of these cities, which provide a snapshot of the concentration levels to which populations are actually exposed. The results of this study showed that populations in low- and middle-income areas are exposed to higher concentrations than those in high-income areas. The analysis of the relative contribution of fine particles to coarse particles shows that PM2.5 contributes to PM10 at less than 40% in Korhogo but more than 50% in Abidjan. Daily average concentrations of PM2.5 are all above WHO standards, and are 2 to 8 times higher in Korhogo, while in Abidjan they are up to 4 times higher. The daily profiles of the mean hourly concentrations of the sites are similar across all sites in Korhogo, while in Abidjan, that of some sites show some differences. This study, by the methodology used, offers an opportunity for different research teams to assess at lower cost the population's exposure levels to urban particulate pollution.

Spatial and Temporal Variability Analysis and Mapping of Reference Evapotranspiration for Jimma Zone, Southwestern Ethiopia

ETo is important parameter in determination of crop water requirement and in irrigation scheduling. The absence of rainfall during four to six months of the year affects crop production. Study was undertaken in Jimma zone, Southwestern Ethiopia, with the objective of evaluating and characterizing the reference evapotranspiration and mapping for planning and management options for Jimma Zone. The study was undertaken at 22 sites of which 14 being from Jimma zone and the remaining eight sites were from around the vicinity of study area. The ETo was estimated using Penman–Monteith method in CROPWAT 8.0 software with monthly datasets of 22 stations for the period of 31 years. The results of ETo were further analyzed by means of geo-statistical tools in R software using gstat package. Maps were created using ordinary kriging combined with regression method. The results have shown that the ETo, have shown moderate to greater variability. The high annual and monthly ETo values were observed around the extreme eastern tip, extreme southern tip and north western tip. In contrary low ETo values were observed in southeastern and western regions. March (4.61 mm/day) and July (2.97mm/day), respectively, presented the highest and the smallest ETo. The ETo for Jimma zone is a good indicator and benefits to farmers to help in planning the water resources of the area for best irrigation water management practices.

Monitoring of Soil Bulk Density in Context with Its Small-Scale Spatial Heterogeneity

The main aim of soil monitoring system is to obtain the knowledge of the most current state and development of soil properties according to concrete threats to soil. To determine the significant changes of soil properties in time, it is important to know spatial variability of concrete soil parameter for concrete site. Only those time changes of the soil parameter are significant, which exceed its spatial variability at the site. The main aim of the study has been focused on the evaluation of small-scale site heterogeneity of equilibrium soil bulk density and the integration of impact of this heterogeneity in evaluation of degradation process of soil compaction in time. As site variation coefficients have considerably varied at standard sampling with five repetitions during monitoring period, one-time detail spatial variability mapping of soil bulk density was realized at 17 repetitions on five selected monitoring sites with different soil type, texture and use. This increase in the number of sampling points helped us to specify and stabilize the values of variation coefficients (between minimum and maximum by standard sampling) as well as the extent of confidence intervals. Standard deviations at the chosen monitoring sites moved from 0.039 to 0.118 g·cm-3 in topsoil and from 0.031 to 0.067 g·cm-3 in subsoil and expressed as variation coefficient 2.9% - 9.2% and 2.0% - 4.9%, respectively. The intervals of significant time changes of soil bulk density for the sites and depths were determined on the base of its site confidence interval (95%) and uncertainty rate of its measure methodology. The time changes of bulk density values between single year-to-year sampling were overlapped by this interval of significant changes to obtain significant bulk density changes in time. This method allowed us to distinguish significant time changes in soil bulk density from insignificant ones. The bulk density value changes on the monitoring sites were significant in the range of six to nine years within observed period 2002-2014 in both depths.

X-ray fluorescence spectrometry applied to digital mapping of soil fertility attributes in tropical region with elevated spatial variability.

Portable X-ray fluorescence (pXRF) spectrometry offers valuable information for prediction models of soil fertility attributes spatial variation, although this approach is yet scarce in tropical regions. This study aims to predict and build spatial variability maps of soil pH, remaining phosphorus (P-Rem), soil organic matter (SOM) and sum of bases (SB) using pXRF results through stepwise multiple linear regression (SMLR) and Random Forest (RF) in a highly variable tropical area. Composite samples from soil A horizon were collected at 90 points throughout the campus of the Federal University of Lavras, Minas Gerais, Brazil, for pH, P-Rem, SOM, SB and pXRF analyses. RF predictions showed the highest accuracies, especially for P-Rem and SB (R² values of 0.66 and 0.55, respectively). Attributes that showed higher R² in punctual predictions also exhibited higher R² in spatial predictions. Data obtained from pXRF in tandem with RF can be used to assist prediction models for soil fertility attributes, consequently enabling the digital mapping of such attributes and helping to improve the knowledge about the spatial variability of such attributes in soils of tropical climate. This technique can therefore assist in the identification and orientation of adequate management practices in tropical agricultural practices.

Assessment of water quality using GIS techniques and water quality index in reservoirs affected by water diversion

This paper assesses the quality of the excess water diverted from the Gurara reservoir to the Lower Usuma reservoir, with declining water resources, based on the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO) permissible limits. A near-laser analysis was carried out on different samples from each of the two reservoirs both in the dry and wet season using geographic information system (GIS) technique and water quality index (WQI). Samples collected were analyzed for pH Temperature, Taste, Odour, Electrical Conductivity (EC), Total Dissolved Solid (TDS), Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Sodium (Na+), Bicarbonate (HCO3-), Chloride (CI-), Nitrate (NO3-), Calcium (Ca2+), Magnesium (Mg2+), Iron (F-) and potassium (K+). The obtained values were evaluated and compared with the standard permissible limits. The result shows a link between the two reservoirs. The physiochemical determinants are within the maximum permissible limits with some slight variations at the Lower Usuma reservoir. The diverted water from the Lower Usuma reservoir was rated as a good water type with index of 62.5% in the dry and 49.7% in the wet season by WHO’s permissible limits, whilst the Nigerian Standard for Drinking Water Quality rates it at 83.3% at the dry season and 69.0% at the wet season. The water from the Gurara reservoir was rated as an excellent type with index of 43.23 % in the dry season and 45.7% in the wet season by WHO’s permissible limits whilst the Nigerian standard for drinking water quality equally rates it at 61.7% and 65.5% in the wet season. According to the correlation matrix, predominant determinants amongst others show both positive and negative correlation at seasonal basis. The spatial variation map shows higher concentration along downstream section at both reservoirs. The study outlined that the surface water of the area is impaired by the anthropogenic activities and needs proper management plan to control further contamination and pollution of the surface water of the area. Further, the surface water of the receiving region needs a proper treatment before its consumptive uses. The application of GIS techniques and water quality index in the assessment of water quality in the context of reservoir systems revealed to be a valuable contribution statistically to the understanding and management of connected water bodies. Future analyses will concentrate on broader applications of this methodology in the context of the understanding and management of reservoir systems in Nigeria. This is, therefore, a call on water managers to put in place routine mechanisms of monitoring the water from reservoirs affected by water diversion, due to the ever-increasing anthropogenic activities around the upstream of reservoir watershed in the coming decades.

Potential of soil resources of Coconut Research Station, Aliyarnagar, Tamil Nadu, India for agro-technology generation

Potential of soil resources of Coconut Research Station, Aliyarnagar of Tamil Nadu Agricultural University and one of the Centers of ICAR-AICRP (Palms), was assessed by soil profile examination and spatial variability mapping. Three soil profiles were examined, one each in A, B and C blocks of the farm, soils were studied horizon wise samples were collected, and fertility parameters were analyzed. Spatial variability of primary nutrients was mapped employing GIS techniques. Soil profile examination revealed the presence of canker nodules in the lower horizons and the depth of the soil was not a constraint for the cultivation of perennial crops. The texture of the soil varied from loamy sand to sandy clay loam. pH was alkaline and electrical conductivity was less than 2 dSm-1. The content of KMnO4-N was low, and Olsen P, NNNH4OAc-K and organic carbon were medium. Land capability class was IIIew and was highly suitable (S1) for coconut, moderately suitable (S2) for cocoa and marginally suitable (S3) for pepper. The soil taxonomic class is fine-loamy mixed, isohyperthermic Fluventic/Typic Haplustepts. Rock outcrops were noticed over 5 per cent of the area. Top soil erosion and seepage problems resulting in temporary water logging are the major fertility constraints associated with this farm. Scrupulous application of organic manures, split application of fertilizers, providing trenches in areas of water logging, etc., are the strategies to overcome the constraints, which are existing in the farm.

Geostatistical Assessment of Spatial Variability of Soil Organic Carbon Under Different Land Uses of Northwestern India

Changes in land use over time can induce spatial variability and these spatial variability patterns may be land use specific. Blanket nutrient management strategies that disregard spatial variability, not only cause economic losses but can impair soil and environmental quality and crop productivity. Geostatistical tools help better in capturing spatial variability than classical tools. This present study was conducted in three different land uses viz., berseem-based, rice–wheat, and poplar-wheat cropping systems prevalent in the northwestern part of India. A total of 144 geo-referenced surface soil samples were collected from these land uses and analyzed chemically to determine SOC and other physicochemical parameters. The highest amount of SOC was associated with poplar-based system, signifying thereby considerable potential for carbon sequestration. The experimental semivariograms models were computed to find the best fitted model for characterizing the spatial pattern of SOC. Gaussian model was found as the best fit for describing the spatial structure of SOC under berseem-based land use; on the other hand, spherical and exponential models were found suitable for rice–wheat and poplar-wheat systems, respectively. The nugget:sill ratio (NS ratio) of SOC was 0.21 for poplar-wheat based land use, suggesting strong spatial dependence, whereas the other land uses exhibited moderate spatial dependence (Berseem based=0.65; Rice-wheat=0.35). Spatial variability maps of SOC were generated using ordinary kriging (OK) technique which helped identify management zones within a field.

Using ForeStereo and LIDAR data to assess fire and canopy structure-related risks in relict Abies pinsapo Boiss. forests.

In this study we combine information from aerial LIDAR and hemispherical images taken in the field with ForeStereo—a forest inventory device—to assess the vulnerability and to design conservation strategies for endangered Mediterranean fir forests based on the mapping of fire risk and canopy structure spatial variability. We focused on the largest continuous remnant population of the endangered tree species Abies pinsapo Boiss. spanning 252 ha in Sierra de las Nieves National Park (South Andalusia, Spain). We established 49 sampling plots over the study area. Stand structure variables were derived from ForeStereo device, a proximal sensing technology for tree diameter, height and crown dimensions and stand crown cover and basal area retrieval from stereoscopic hemispherical images photogrammetry. With this information, we developed regression models with airborne LIDAR data (spatial resolution of 0.5 points∙m−2). Thereafter, six fuel models were fitted to the plots according to the UCO40 classification criteria, and then the entire area was classified using the Nearest Neighbor algorithm on Sentinel imagery (overall accuracy of 0.56 and a KIA-Kappa Coefficient of 0.46). FlamMap software was used for fire simulation scenarios based on fuel models, stand structure, and terrain data. Besides the fire simulation, we analyzed canopy structure to assess the status and vulnerability of this fir population. The assessment shows a secondary growth forest that has an increasing presence of fuel models with the potential for high fire spread rate fire and burn probability. Our methodological approach has the potential to be integrated as a support tool for the adaptive management and conservation of A. pinsapo across its whole distribution area (<4,000 ha), as well as for other endangered circum-Mediterranean fir forests, as A. numidica de Lannoy and A. pinsapo marocana Trab. in North Africa.

EVALUATION GROUNDWATER QUALITY BY USING GIS AND WATER QUALITY INDEX TECHNIQUES FOR WELLS IN BARDARASH AREA, NORTHERN IRAQ

Studying groundwater quality in arid and semi-arid regions is essential significant because it is used as a foremost alternative source for various purposes (human and animal consumption, economic, agriculture and irrigation). Geographic Information System and Water Quality Index techniques were utilized for visualizing and evaluating the variations of groundwater quality in the studied area. Total twelve wells were sampled and twelve groundwater quality (chemical) parameters; pH, Total Alkalinity, Total Hardness (TH), Total Dissolved Solid (TDS), Electrical Conductivity (Ec), Potassium (K), Nitrate (NO3), Sulfate (SO4), Chloride (Cl), Calcium (Ca), Magnesium (Mg) and Sodium (Na) were analyzed in the laboratory. Inverse Distance Weighted technique was used as a useful tool to create and anticipate spatial variation maps of the chemical parameters. Predicting or anticipating other areas not measured, identifying them and making use of them in the future without examining samples. The results of this research showed that 8.3% of the studied wells have excellent groundwater quality, and almost sampling wells about 75% found in good groundwater quality, while findings of groundwater quality of 16.7% studied wells belong to poor water quality due to standards of Water Quality Index. Moreover, spatial analysis in term of groundwater quality map showed that Excellent groundwater quality was detected in well 3, very good groundwater potential was noticed in six studied wells (wells 2, 6, 8, 10, 11 and 12), and other sampling wells (wells 4 and 7) were observed as good groundwater quality, while poor water quality was observed in wells (well 1 and 5). Hence, spatial distribution maps showed that the almost groundwater quality in the area about 1046.82 km² (99.04%) are suitable for drinking purpose, whereas proximate 10.18 km² (0.96%) are observed as poor water quality and inappropriate for consumptions especially in the southern part of the area.