Silt Content Research Articles

An advanced machine learning-based mathematical equation for predicting compression index from readily-available soil physical properties

ABSTRACT The Compression index, known as Cc, plays a crucial role in geotechnical design. However, the conventional approach to ascertain Cc is not only expensive but also time-intensive. This paper proposes an innovative modeling approach to develop a Deep Neural Network (DNN)-based formula for the prediction of Cc incorporating readily accessible physical properties of soil, including specific gravity (G), saturation degree (Sr), liquid limit (LL), silt content (SC), and clay content (CC). To assess the predictive performance of the proposed formula, various metrics were employed, such as determination coefficient (R²), root mean square error (RMSE), mean absolute error (MAE), and Nash–Sutcliffe Efficiency (NSE). From the collected dataset, 608 samples were used as the training set for the DNN model, while the remaining 152 samples were designated as the testing set. The R², RMSE, MAE, and NSE values for the training and testing sets were 0.9821 and 0.9935; 0.126 and 0.098; 0.083 and 0.074; 0.9812 and 0.9922, respectively. These results indicate that the developed equation demonstrates outstanding predictive accuracy for estimating Cc. Furthermore, the comparative analysis underscores that the proposed DNN-based formula significantly outperforms empirical equations and multilinear regression (MLR) model in predicting Cc with higher accuracy.

Long-term transfer of 137Cs in sensitive agricultural environments after the Chornobyl fallout in Sweden.

In this study, the long-term transfer of 137Cs from soil to grass on Swedish farms and fields, heavily contaminated after the 1986 radioactive fallout, was investigated. The study spans over 8-14 years, beginning in June 1986, and covers various soil types and agricultural practices. The transfer of 137Cs from soil to grass was highly variable, with transfer factors ranging from 1.0×10-5 to 0.357m2kg-1. Higher values were observed on fields with sandy loam, loamy sand, and organic soils, and lower values on fields with a high clay content. The transfer of 137Cs to grass generally exhibited an exponential decline across the majority of fields over the years. The rate of decrease was most pronounced in clay loam and silty loam soils, while it was least evident in sandy loam, sandy soils, and peat soils. The soil properties and farming practices were more important for 137Cs uptake than the initial deposition density. The transfer factor had a negative correlation with soil pH, clay, and fine silt content. No significant relationships were found with other soil variables, such as soil organic matter content and plant available potassium concentration. The median effective half-life of 137Cs in the grass was 4.5 years, with a range of 2-18 years. The uptake of 137Cs by plants did not correlate with the potassium concentration in grass tissues; however, the activity concentration of 137Cs in grass correlated negatively with the potassium content in the plants grown on fields with high deposition levels.

Online analysis of Amazon's soils through reflectance spectroscopy and cloud computing can support policies and the sustainable development.

Analyzing soil in large and remote areas such as the Amazon River Basin (ARB) is unviable when it is entirely performed by wet labs using traditional methods due to the scarcity of labs and the significant workforce requirements, increasing costs, time, and waste. Remote sensing, combined with cloud computing, enhances soil analysis by modeling soil from spectral data and overcoming the limitations of traditional methods. We verified the potential of soil spectroscopy in conjunction with cloud-based computing to predict soil organic carbon (SOC) and particle size (sand, silt, and clay) content from the Amazon region. To this end, we request physicochemical attribute values determined by wet laboratory analyses of 211 soil samples from the ARB. These samples were submitted to spectroscopy Vis-NIR-SWIR in the laboratory. Two approaches modeled the soil attributes: M-I) cloud-computing-based using the Brazilian Soil Spectral Service (BraSpecS) platform, and M-II) computing-based in an offline environment using R programming language. Both methods used the Cubist machine learning algorithm for modeling. The coefficient of determination (R2), mean absolute error (MAE) and root mean squared error (RMSE) served as criteria for performance assessment. The soil attributes prediction was highly consistent, considering the measured and predicted by both approaches M-I and M-II. The M-II outperformed the M-I in predicting both particle size and SOC. For clay content, the offline model achieved an R2 of 0.85, with an MAE of 86.16gkg⁻1 and RMSE of 111.73gkg⁻1, while the online model had an R2 of 0.70, MAE of 111.73gkg⁻1, and RMSE of 144.19gkg⁻1. For SOC, the offline model also showed better performance, with an R2 of 0.81, MAE of 3.42gkg⁻1, and RMSE of 4.57gkg⁻1, compared to an R2 of 0.72, MAE of 3.66gkg⁻1, and RMSE of 5.53gkg⁻1 for the M-I. Both modeling methods demonstrated the power of reflectance spectroscopy and cloud computing to survey soils in remote and large areas such as ARB. The synergetic use of these techniques can support policies and sustainable development.

A study of the undrained monotonic behavior of geotextile reinforced sand-silt mixtures using triaxial tests

“Investigating the behavior of silty soils reinforced with geotextile layers in terms of shear strength and deformation in a laboratory setting is the study’s objective described in this paper. This work includes an experimental study based on a series of undrained monotonic triaxial tests, which were carried out on clean sand from Chlef, medium dense (Dr = 50%), mixed with silt content fluctuating between 0 and 30%. The mechanical behavior was examined and discussed in this paper by varying the number of geotextile layers (Ng = 1, 2, 3) and the fines content where the samples were consolidated under 100 kPa confining pressure. Experimental results on unreinforced and reinforced silt/sand soils by geotextile layers show that the quantity of geotextile layers is growing in the studied samples improves the shear strength characteristics of the soil, nevertheless, lessen the radial deformations cause the pore water pressure to rise instead. However, the pore water pressure increases while the deviatoric stress decreases as the percentage of fines increases.”

Boron Behaviors in Upland Humid Tropical Soils: A Case of Plant-Available Implication for Cassava

ABSTRACT Understanding the role of soil boron (B) through its reaction, mobility, and availability could provide effective B nutritional management for a cassava crop (Manihot esculenta crantz). This study investigated a soil B status suitable method for making B fertilizer recommendation through determining the B sorption index and the chemical fractionation of soil B and available B in soils, using single extractants in 11 benchmark soils intensively cultivated for cassava in northeast, Thailand. All soils studied were considered low B-sorbed soils that were equally well described using either Langmuir or Freundlich models, with respective adsorption capacities of 2.00–17.22 mg kg−1 and 0.91–4.31 L mg−1. The B desorption index exhibited hysteresis desorption behavior for all soils. Boron adsorption by the soils significantly showed a positive correlation (>0.75, p ≤ .01) with organic carbon, silt, amorphous aluminum, and silicon contents. Of the total B, the native B pool in the soils was mostly in the residual fraction, contributing 70–80%, while the readily soluble fraction contributed only 0.07–0.59%. Among the soil extractants tested, only hot CaCl2 and NH4OAc adequately assessed soil B availability for cassava, while they were less extractability to extract B from total B. Chemical fractions of B could all be used for available B assessment for cassava with a residual B fraction being superior, although this was unlikely to contribute significantly to plant-available B in the short term, but it was a potential B reserve that could maintain adequate B status in the long term throughout the cassava growing period.

Microtopography-induced hydrological heterogeneity promotes the co-assembly of vascular plant and biocrust communities, providing synergistic protective functions for the Great Wall.

The Great Wall in China, constructed from rammed earth, faces threats from natural erosion. Vascular plants and biocrusts have enhanced the stability of the Great Wall through various mechanisms; however, understanding of the colonization processes of vascular plants and biocrusts on the wall, as well as their protective mechanisms, remains limited. This study investigated the vascular plant communities, biocrusts, soil moisture content, soil properties, aggregate mechanical stability, aggregate water stability, and soil erodibility factors across seven fine-scale microtopographies of the Great Wall (lower, middle, and upper zones on the east and west faces, as well as the wall crest). After rainfall events and under no-rainfall conditions, soil moisture content was higher at the crest compared to the lower zones on both sides; this demonstrates that microtopography significantly influences soil moisture distribution through rainfall distribution. Soil moisture content was positively correlated with variables associated with vascular plant communities (except evenness) and moss crust (p<0.05). This suggests that the microtopography of the wall and its induced water heterogeneity drive the distribution pattern of vascular plant communities and moss crusts. Vascular plant communities and moss crusts significantly enhanced the mechanical and water stability of soil aggregates, reducing soil erosion susceptibility by providing physical protective cover, increasing the content of mechanically stable and water-stable macroaggregates, and enhancing soil silt and clay content, soil porosity, and water-holding capacity. Based on the regulation of vascular plant communities and biocrusts by microtopography, a restoration framework was proposed, offering a theoretical foundation and practical methods for the protection of the wall and similar earthen heritage sites.

Environmental and Ecological Risks Posed by Sediment Heavy Metals in Reservoirs: A Preliminary Study from Northwest Türkiye

Reservoir sediments are an important component of aquatic ecosystems. Concentrations, sources, pollution and ecological risks of heavy metals pose serious risks on sustainable management of these ecosystems. This research focuses on heavy metal contents, physicochemical properties, environmental and ecological risks of sediments in four reservoirs (Ayvacık, Bayramdere, Bayramiç, and Umurbey) in Northwest Türkiye. Bayramiç reservoir had greater sediment Al, Cu, Fe, Mn concentrations, clay and silt contents than the other reservoirs (Ayvacık, Bayramdere, and Umurbey). In all four reservoirs, sediment heavy metals were generally of natural origin. Although sediment pollution index was identified as “considerable contamination” for Mn, such a case was not detected for the other heavy metals (Cd, Co, Cr, Cu, Fe, Ni, Pb, and Zn). An ecological risk assessment was made for reservoir sediments and a “low contamination” was detected.

Structure and properties of paleosols of the last two interglacial cycles of the Khovaling Loess Plateau, Tajikistan (Obi–Mazar section)

Abstract Significant thicknesses, a large number of paleosols, and an impressive chronological framework place the loess–paleosol series of the Afghan-Tajik depression on a par with the famous sections of the Chinese Loess Plateau. Based on the results of field stratigraphy, description of the macro- and micromorphological structure, field magnetic susceptibility measurements, and study of the chemical and grain-size compositions, a comprehensive characterization of the structure, properties, and formation conditions of paleosol horizons and loess layers was carried out. Three loess units and two pedocomplexes are distinguished in the late and upper middle Pleistocene deposits of the Obi-Mazar section. These sediments are characterized by high silt and carbonate content and the presence of loess with pedogenic features. Pedocomplex PC1, consisting of three paleosols, according to the stratigraphic position and absolute dating, corresponds to MIS 5. Pedocomplex PC2, consisting of two developed paleosols separated by loess, is correlated with MIS 7. The properties of the studied paleosols together with modern soil distribution in the region allow for the reconstruction of the soil type of PC1 and PC2 of the Obi-Mazar section with the genesis of the Calcisols–Kastanozems groups.

Systematic Synthesis of Knowledge Relating to the Hydrological Functioning of Inland Valleys in Sub-Saharan Africa

The potential of inland valleys to enhance food security and improve agricultural resilience to climate change in Africa is constrained by a limited understanding of their hydrological functioning and inadequate water management. In order to synthesize knowledge on hydrological responses in inland valley areas, this work reviewed 275 studies from tropical Sub-Saharan Africa (SSA). Data from the literature search were collected from Scopus™, ScienceDirect™, Web of Science™, Google Scholar™, and doctoral theses repositories such as ZEF, HAL, and Theses.fr, covering studies published from the inception of these databases through 31 May 2023. Our approach involved, firstly, a bibliometric analysis of all papers to gain insights into research trends and interests. Secondly, we performed a quantitative synthesis of results from 66 studies examining stream flows in a set of 79 inland valleys to better understand factors that govern runoff dynamics in these environments. Correlative analyses and clustering methods were applied to identify potential links between runoff and watershed physical parameters. The findings highlight the varied responses of inland valleys over both time and space, influenced by a combination of catchment drivers. The correlation matrices between hydrological indices and physical parameters indicate a strong relationship among runoff and a range of parameters, of which the most significant are rainfall (R2 = 0.77) and soil silt content (R2 = 0.68). Challenges in accurately spatializing information related to potential determining components of the water cycle, such as groundwater dynamics and soil moisture, seem to have limited the exploration of interactions between river flow, soil moisture, and groundwater. Future works should prioritize the development of accurate and user-friendly hydrological models that balance complexity and data availability to enhance the understanding of inland valley behavior at fine scales and consolidate food security in Africa.

Phosphorus Dynamics in Managed and Natural Soils: SEM-PLS Analysis of Vaccinium, Forest, and Grassland Ecosystems.

Phosphorus (P) availability in soils is often constrained by its accumulation in non-labile phosphorus (NLP) forms, limiting its accessibility to plants. This study examines how soil physical properties, chemical characteristics, and climatic conditions influence phosphorus fractionation and the transformation of NLP into plant-available labile phosphorus (LP). Utilizing global structural equation modeling (SEM), we found that silt content enhances organic phosphorus fractions, including NaHCO3-Po and NaOH-Po. In the upper 30 cm of soil, pH decreases the availability of NaHCO3-Po and NaOH-Po while stabilizing NLP, highlighting its essential role in phosphorus cycling under acidic conditions. In deeper soil layers, pH facilitates phosphorus mobilization from NLP pools, with effects varying across fractions. Long-term studies on Japanese Vaccinium soils reveal that pH and electrical conductivity (EC) management significantly promote NLP-to-LP conversion, primarily through NaOH-Po, thereby improving phosphorus use efficiency. These findings underscore the critical importance of prioritizing chemical property management over physical modifications to optimize nutrient cycling, preserve soil fertility, and reduce reliance on external phosphorus inputs in agricultural systems. Our study emphasizes the need for integrated approaches to achieve sustainable phosphorus management in both natural and managed ecosystems.

Hydrological signatures in Brazilian catchments: a machine learning approach for spatial estimates

This study investigates the estimation of hydrological signatures in Brazilian catchments using physical attributes and machine learning algorithms. Using CABra’s dataset with 735 catchments, we tested 163 signatures with regression techniques, including Random Forest, Gradient Boosting, and Support Vector Regression (SVR). A key aspect was the algorithmic approach, providing models with topographic (area, elevation, slope), climatic (precipitation, evapotranspiration, aridity index), soil (silt, clay, organic content), and land cover attributes without assuming correlations. This enabled the models to uncover complex patterns. Cross-validation (k-fold) showed most signatures were satisfactorily predicted (R2 > 0.7), suggesting their application in ungauged basins. Climatic factors, like precipitation, were crucial for predicting most signatures, especially high-flow, while silt content and latitude influenced low-flow and baseflow. Slope and latitude were key for basin dynamics, influencing the flashiness index, and land cover was important for low-flow. CatBoost was the best model. The SHapley Additive exPlanation (SHAP) analysis highlighted the importance of variables with low linear correlation.

Detecting environmental trends to rethink soybean variety testing programs

AbstractVariety testing programs (VTPs) use multi‐environment trials (MET) to evaluate and report the performance of commercially available and pre‐commercial soybean (Glycine max L. Merr.) varieties targeting a specific set of environments. Adequate modeling of the environmental variability and genotype–environment interactions (G × E) within the VTP would help farmers and seed companies decide which variety to choose or recommend. We propose an approach to characterize environments using the soybean data from the University of Missouri VTP. We modeled an environmental trend (EnvT) based on the phenotypic mean performance and the observed phenotype in each environment. The environments were classified into four different EnvT environment types, and soil and climate data were used as predictors of the EnvT through eXtreme Gradient Boosting (XGBoost) model. Temperature on late vegetative and flowering, soil‐saturated hydraulic conductivity, and silt content were key drivers of EnvT. The approach identified overrepresented environments (62%) and increased the ratio between variety and G × E variance. A simulation case study verified that the random removal of overrepresented sites from the dataset quickly degraded G × E analysis, implying that increasing the number of underrepresented sites is recommended. Our results demonstrate that environmental characterization is essential for optimizing resource allocation within VTP, thereby supporting the end goal of aiding farmers to utilize the best varieties for their production environment.

Estimating soil salinity level by pedotransfer functions

Abstract In this study, the electrical conductivity (EC) of cultivated fields were predicted by pedotransfer functions (PTFs) using basic soil properties as variables in stepwise analyses. Before using PTFs, 207 soil samples were divided into development and validation datasets. This division was done 10 times to assess the accuracy and reliability of the PTFs. According to the principal component analysis (PCA), the EC values had higher load in PC1 and PC2 with clay, exchangeable Na, Ca, Mg and K contents. The EC values had significant positive correlations with pH, clay, exchangeable Ca, Mg, K, Na content, and negative correlations with silt and sand content. According to the stepwise analyses, 10 PTFs or linear multiple regression models were obtained using development data sets. The accuracy in development data sets and reliability in the validation data sets for these PTF models were assessed with R2 and RMSE values. The higher mean R2 and the lower mean RMSE values were obtained in the development data set when compared to the validation data set. The PTF-7 including clay, exchangeable Na, Mg and Ca was suggested to predict soil EC values of cultivated fields. It was determined that clay and exchangeable Na, Mg and Ca content were the most effective soil properties on predicting the EC values of cultivated fields. Keywords: Salt, EC, exchangeable cations, soil texture

SUGARCANE LAND USE AND WATER RESOURCES ASSESSMENT IN GAGARAWA LGA, JIGAWA STATE, NIGERIA

The availability of water resources for sugarcane production in Gagarawa, Jigawa State, Nigeria, a potential area for large-scale sugarcane production, was assessed. Sugarcane (Saccharum officinarum L.), a tall perennial grass belonging to the grass family Gramineae, is a long-duration crop that produces enormous amounts of biomass. It is the major crop from which sugar is produced. With Nigeria’s growing population, demand for sugar is rising, but production is low. Water resources are key to producing sugarcane. Many areas in northern Nigeria may be suitable for sugarcane, except for water availability. Remote sensing data from Landsat 7.0 and STRM 30m were used to analyse the physical land qualities. Annual rainfall (500mm) and evaporation (73.1 mm/day) were obtained from GIOVANNI &amp; Power LARC. Infiltration and silt sedimentation were determined using soil infiltration test and siltation from runoff silt content (204mm/hr). Sugarcane water requirements and groundwater were determined using CropWat model 8. The analysis indicated that the land is perfect for rainfed and irrigated sugarcane cultivation, with an average annual rainfall of 500 mm. Sugarcane requires 2088 mm of water, resulting in a deficit of 1588 mm, which is to be supplemented by irrigation. Groundwater potential of 1239.4 mm was available but still indicates a deficit. Alternative sources to compensate for the deficit are River Hadejia and the field's construction of rainwater harvesting structures. The recommendation was to consider using surface and groundwater conservation in addition to the annual rainfall in the study area.

Effect of silt fines on the undrained monotonic behavior of compacted tuff soil

The present study explores the influence of silt content on the undrained monotonic behavior of compacted tuff. All undrained triaxial tests were performed at both relative densities Dr = 50 and 90% and compacted with the optimum water content on tuff soil mixed with silt in the range of 0 to 50%. Experimental results show that adding fines content (FC) up to 20% increases the resistance of dense compacted tuff (Dr = 90%) by about 35% for 100 kPa of confining pressure, and the addition of 10% silt fines results in a maximum increase of 15.71% in the medium dense state specimen (Dr = 50%). The deviator stress reveals a decrease by adding more than 20% of silt. Moreover, the soil cohesion was found to attain maximum values with the optimum silt percentage of FC = 10% for medium-density samples (Dr = 50%) and FC = 20% for dense samples (Dr = 90%), respectively. Finally, the study showed a direct correlation between the cohesion of the soil prepared in a dense state (Dr = 90%) and the soil’s maximum dry density (MDD). In particular, the maximum dry density corresponds to a higher cohesion.

Soil-hydrological properties in response to grazing practices in the alpine meadows of the Qinghai-Tibetan Plateau

Abstract Alpine meadows of the Qinghai-Tibetan Plateau (QTP) are experiencing severe degradation due to intensified human activity and climate changes. However, there has been little attention paid to the effects of grazing practices on the soil-hydrological properties of degraded alpine meadows. In this study, three grazing practices were established in an alpine Kobresia meadow: free grazing, reduced grazing, and grazing exclusion. We found the 0-10 cm soil water retention capacity (SWR) and plant available water content (AWC) in grazing exclusion treatment were higher than that reduced grazing and free grazing treatments, whereas the 20-40 cm display the opposite pattern. The AWC and SWR variations were closed related to soil properties, the redundancy analysis shown that SWR and AWC were positive related to soil organic matter (SOM), total porosity (TP), capillary porosity (CP), while negative correlations with soil bulk density (BD), clay, and silt content, and RDA1 and RDA2 explained 81.71% of the total variability in SWR and AWC. Structural equation modeling found that soil organic matter (SOM) was identified as the most important factor affecting SWR, with a direct standardized coefficient of 0.91, while CP was the key factor influencing AWC, with a direct standardized coefficient of 0.97. Therefore, the higher 0-10 cm SWR and AWC in grazing exclusion treatment may attributed to its higher SOM and CP, respectively. Furthermore, root biomass can affect SWR and AWC via its direct effect and direct through altering BD and SOM. Our study suggests that the response of soil hydrological properties to grazing practices was different, grazing exclusion only increase topsoil water retention capacity but not favor deep soil water retention capacity. We thus should take different grazing practices to improve the soil water conservation of degraded grassland in future grazing management.

Modeling Cork Yield, Thickness, Price, and Gross Income in the Portuguese Cork Oak Montado

The cork oak (Quercus suber L.) woodlands, known as montados in Portugal, hold significant economic, cultural, social, and environmental value. They are found in the Mediterranean Sea basin, particularly in the Iberian Peninsula, and sustain various activities like silvopastoralism, with cork being a primary product. Despite its economic significance, challenges such as climate change threaten its sustainability. This study aimed to analyze the edaphoclimatic variables affecting cork yield, thickness, price, and gross income in the Alentejo region of Portugal. A total of 35 farmers were selected for the data collection included in this study. Multivariable linear regressions were performed to establish relationships between cork yield, thickness, price, and gross income as dependent variables, various edaphoclimatic factors, and tree densities. A higher tree density correlates with an increased cork yield but a decreased cork thickness. Soil pH affects cork yield and thickness, with a lower pH favoring higher cork yields but thinner cork. A higher clay and silt content in horizon soil C enhances cork thickness and raises the price but reduces the cork yield. Higher accumulated precipitation and temperatures contribute to higher yields and thicknesses of cork. It is concluded that the relationships between the dependent and the independent variables are complex but partially explainable. Understanding these relationships is paramount to ensure sustainable management practices are adopted that are capable of addressing issues raised in the current context of climate change.

Polycyclic aromatic hydrocarbons in surface sediments of the western Bay of Bengal: Distribution, sources, and ecological risk assessment

This study investigated the distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Western Bay of Bengal (WBoB). Coastal, shelf and slope sediments from the WBoB, collected from different research cruises, were analysed for 16 priority PAH pollutants. Total PAHs (TPAHs) were in the range of 1.87–918.79 ng/g and exhibited a significant association with organic matter and silt content with a predominance of high molecular weight (HMW) PAHs congeners. The preferential degradation of the labile low-molecular-weight (LMW) PAHs resulted in the sedimentary accumulation of HMW congeners. A comparison with reported values from other oceanic areas revealed a relatively low concentration of PAHs in WBoB. The isomeric ratios of PAHs could suggest a pyrogenic or petrogenic (crude oil) origin of PAHs. Principal component analysis indicated the dominance of HMW PAHs (petrogenic or combustion) over the LMW fraction. Based on sediment quality guidelines, four congeners [Pyrene (Py), Benzo[a]anthracene (BaA), Chrysene (Ch), and Dibenzo[a,h]anthracene (DbA)] exceeded the threshold effect levels, indicating an adverse impact of these PAHs on the benthic fauna occasionally. The corresponding risk quotients further indicated a moderate risk caused by Py, BaA, and Benzo[b]fluoranthene (BbF) to the biota. This study underscores the importance of proactive management and mitigation strategies to safeguard these vital oceanic ecosystems from the adverse effects of PAHs and other hazardous materials.

Shear band analysis of silt-clay transition soils under three-dimensional stress-strain conditions

This paper investigates shear banding as a possible failure mode for silt–clay transition soils under general three-dimensional stress conditions. Drained and undrained true triaxial tests with constant b values were performed on tall prismatic specimens of such soils with systematically varying silt contents. Based on the values of critical plastic hardening modulus, shear banding does not govern the strength characteristics of the soils for b values less than 0.2. For larger b values, shear band formation is essentially critical as it takes place in the hardening regime of the stress–strain curves prior to the smooth peak failure points. An increase in silt content appears to move the onset of shear banding to lower levels of shear in the stress–strain relations of the silt–clay transition soils. It is also demonstrated that a non-associated constitutive model with a single hardening law is capable of accurately predicting the onset of shear banding in normally consolidated silt–clay transition soils based on bifurcation theory.

Assessment of soil degradation in northern Basrah governorate using geospatial techniques and spectral Indices

This study was conducted to evaluate the degradation of soils in northern Basra Governorate using remote sensing techniques, geographic information systems and some spectral indicators. The soils of the region are characterized by being of calcareous sedimentary origin, belonging to the Entisols rank. The study area is located north of Basra Governorate, southern Iraq, within the administrative borders of Al-Qurna District, extending south to Al-Deir District. It is bordered to the east by the Shatt Al-Arab River and lies between longitudes 47°22'10" - 47°39'8" east and latitudes 30°44'41" - 31°3'49" north, with an area of ​​429.681 km2. The results of the physical analysis showed that there was a difference in the distribution pattern of soil particles (sand, silt and clay) within a single soil site or between different soil sites. This is due to the variation in the sedimentary environment of the studied sites. It was noted that the content of clay and silt was high in general depths of the sites compared to the small amount of sand in some sites. The dominance of silt particles was in most sites, ranging between 206.90 - 703.20 g kg-1, then clay, ranging between 202.80 - 659.20 g kg-1, while sand ranged between 16.40 - 425.30 g kg-1. The results of the chemical analysis showed that the organic matter content of the sites ranged between 2.1 - 16.6 g kg-1. The highest values ​​appeared in the surface depths, especially at site 6, and the soil salinity ranged between non-saline soils and highly saline soils, ranging from 3.33 to 90.82 dsm-1. The lowest salinity appeared at site 4, reaching 3.33 dsm-1, which is affiliated with the Kutuf Al-Anhar section located east of Shatt Al-Arab.