Soil Specimens Research Articles

Triaxial Mechanical Characteristics and Microscopic Mechanism of Graphene-Modified Cement Stabilized Expansive Soil

To investigate the effect of graphene (G) on the triaxial mechanical characteristics of cement stabilized soil, a triaxial unconsolidated and undrained (UU) test was conducted on cement stabilized expansive soil (CES) and graphene-modified cement stabilized expansive soil (GCES) with 0.05%, 0.1%, 0.15%, and 0.2%G content, respectively. The experimental results showed that compared with CES, the deviatoric stress-strain curve of GCES showed a more obvious softening characteristic. The addition of G had a good modification effect on the triaxial mechanical characteristics of CES, and with the increase of the content of G, the compressive strength and shear strength of CES increased first and then decreased, and reached the best value when the G content was 0.1%. The failure angle predicted by the Mohr-Coulomb failure angle formula had a good correlation with the measured failure angle of soil specimens, so it could provide help for the prediction of soil failure surface in practical engineering. Besides, the scanning electron microscope (SEM) analysis indicated that the internal structure of CES was improved due to G addition.

Utilization of Blast-Furnace Slag as a Standalone Stabilizer for High Sulfate-Bearing Soils

This paper presents experimental results and analysis of sulfate-bearing soils treated with ground granulated blast-furnace slag (GGBS). The experiments involve the unconfined compression strength test, shrinkage, free swelling, suction measurements, and microstructural examination. Short- and long-term swelling tests were conducted to inspect the durability of GGBS stabilization against the sulfate-induced heave. The concept of the shrinkage curve was employed to elucidate how GGBS stabilization alleviates soil shrinkage behavior and alters the pore size distribution. The results manifested that 7% GGBS was sufficiently adequate to improve the 28-day strength of the tested sulfate-bearing soils about five times. The GGBS treatment mainly results in the decline of calcium sulfate content and the formation of calcium silicate hydrate, ettringite, and calcite. The results of long-term swelling tests indicated a delayed sulfate-induced heave that started beyond a month from the time of exposing the treated soils to water. The delayed heave was still not significant as compared with that of the untreated control soil specimens. Accordingly, it is recommended that the treated sulfate-bearing soils are tested with the selected GGBS content for any delayed swelling before application in the field. The GGBS treatment has significantly escalated suction magnitude during curing mainly due to the consumption of water in the hydration process and the formation of ettringite.

Bidirectional Shear Wave Velocity Measurements to Track Fabric Anisotropy Evolution of a Crushed Silica Sand during Shearing

AbstractContinuous bidirectional shear wave velocity measurements were performed in the vertical (V) and horizontal (H) directions to characterize fabric evolution of triaxial soil specimens during...

Monitoring of soil moisture and temperature distributions in seasonally frozen ground with fiber optic sensors

The evolution of moisture and temperature fields plays an important role in governing soil behavior, which heavily influences the performance of infrastructures built on the ground soil. However, conventional geotechnical instrumentation presents many limitations in the monitoring of seasonally frozen soils in cold regions. This study investigates the feasibility of actively heated fiber Bragg grating (AH-FBG) in measuring the temperature, water content, and ice content of seasonally frozen soil through laboratory tests and field monitoring. The working principle of the AH-FBG monitoring system is introduced in detail. A series of laboratory calibration tests were performed on soil specimens to explore its performance. Long-term in-situ monitoring was carried out on the Loess Plateau in northwestern China. Results show that the AH-FBG technique can be applied to measure the total water content of soils using the Côté and Konrad model. In the field monitoring, the freezing-thawing process of frozen soil was captured by measuring soil temperatures and ice contents during field monitoring, and the maximum freezing depth was deduced. The AH-FBG technique is verified to be a powerful tool in estimating the actual behavior of in-situ ground soil and provides rich information on multi-field interactions in cold regions.

A homogenization approach to estimate the shear modulus of spatially variable soil materials

Engineers often use seismic site response analyses to evaluate the propagation of seismic waves through a soil deposit. These analyses have traditionally relied on dynamic properties (e.g., the maximum shear modulus, Gmax, and shear modulus reduction curves G/Gmax) measured on homogeneous soil specimens. However, soil properties are not uniform, and it is common to see variabilities at different scales. This study uses physical models with controlled variability to evaluate the Gmax and G/Gmax in heterogeneous soil samples to reflect the effects of soil variability. We used a 3D soil printer to create heterogeneous soil models of 20x20x20 cm that match target random field simulations generated by spatially varying the liquid limit on clayey-type soils. The models were used to sample cylindrical specimens, then tested in a torsional shear rheometer to measure Gmax and G/Gmax. The results show that Gmax and the G/Gmax curves are affected by the internal specimen variability, particularly by the coefficient of variation (COV) in the underlain random fields. Using the experimental results, we also show that the Hill [1] approach for estimating properties of composite materials provides a good estimation for the experimentally measured G/Gmax curves in a heterogeneous soil media, especially in specimens with low to medium variability. Finally, we evaluated the performance of the homogenization bounding theory of Hashin and Shtrikman [2], also formulated for composite materials, on estimating Gmax. We find that the Gmax of specimens with low and medium variability can be reasonably estimated using the upper bound. In contrast, samples with high variability are better estimated using the lower bound.

Mechanical behaviour and loading rate dependency of gypsum-mixed fine-grained soils

Gypsum is regarded as an environmentally friendly binding material and is widely used to enhance the engineering properties of soft fine-grained soils. However, the time-dependent strength and deformation characteristics of fine-grained soils stabilised with gypsum have not yet been thoroughly investigated and rational evaluation of these characteristics will assist in the formulation of cost-effective and reliable design approaches. In this study, the time-dependent mechanical behaviours of gypsum-mixed fine-grained soil (GMFS) specimens were investigated under unconfined monotonic loading conditions, considering ageing periods of 3–90 days and five different loading rates (LR = 0.0005–1.0%/min). The results revealed that the unconfined compressive strength and stiffness of the GMFS specimens initially decreased with ageing and finally became stable after 14 days and 28 days of ageing for water/gypsum ratios of 1.30 and 1.60, respectively. Furthermore, the strength and stiffness of the GMFS specimens increased with an increase in LR.

Experimental and Numerical Evaluation of the Effect of Nano Calcium Carbonate on Geotechnical Properties of Clayey Sand Soil

The effect of nano-CaCO3 on the geotechnical properties of clayey sand (SC) soil was investigated. SC soil containing 10%, 20% and 30% clay and 0.3%, 0.7%, 1.1% and 1.5% nano-CaCO3 were cured for 7, 14 and 28 days and then subjected to uniaxial compression testing. The experimental results were analyzed numerically by the group method of data handling using an artificial neural network. Crystalline phases were analyzed by x-ray diffraction (XRD) to study the microstructure of soil specimens improved with nano-CaCO3. The addition of nano-CaCO3 to SC specimens, especially those with lower clay contents, increased their uniaxial compressive strength and the compressive strength increased over time. An optimum nano-CaCO3 level of 0.7% was determined for soil containing 10% and 20% clay and 1.1% for soil containing 30% clay. The results indicated a decrease in deformation and increase in stiffness of the soil with the addition of nano-CaCO3. The effect of nano-CaCO3 on the ultimate compressive strength of the soil in the XRD patterns indicated an increase in the recrystallization of the particles. Numerical analysis of the experimental results found a correlation for predicting the uniaxial compressive strength of the improved SC soil with a mean error of 4%.

Impact of fertigation schema on yield and chemical composition of strawberry (Fragaria×ananassa Duch.)

A frequent fertigation of garden strawberry with solute mineral fertiliser in accord with the plant growth phase allows a more efficient mineral nutrient absorption compared to a single application of larger fertiliser amount. Field studies on medium loam-granulometry sod-podzol soil in fruiting garden strawberry plantations were carried out for three years in the Moscow Region to evaluate the impact of fertigation regimes on strawberry yield and the main nutrient content in soil and plant leaves. In study setup, the control crop grew with a no-fertiliser drip irrigation, schema 1 included frequent (once in 3 days) mineral fertiliser drip application at 2-3 g/l, schema 2 — 4-6 g/l solution application twice less often (once in 6 days). Materials and methods. Yield was estimated by weight per plot area unit, plant samples analysed with conventional wet ashing. Nitrate nitrogen was determined in ionometry, exchangeable ammonium — in photocolourimetry, mobile phosphorus and potassium specimens — by the Kirsanov’s CINAO-modified method. The article presents registration data, averaged leaf chemical assays and content dynamics of major soil macronutrients over a three-year observation period. Conclusions. A significant increase in three-year total yield was observed with the mineral fertiliser fertigation schema in the Ducat strawberry cultivar; a supraoptimal phosphorus accumulation in leaves of the Rusich cultivar was facilitated by a less frequent application of concentrated fertiliser solution; a maximal nitrogen amount in Ducat leaves was observed with fractional fertigation; in a lower-yield season, concentrated mineral fertiliser fertigation contributed to the increase of mobile phosphorus and potassium specimens in soil in mid growing season. A greater correlation was observed between the soil content of mobile potassium and its uptake by strawberry plants.

Filter paper method for suction measurement using electrical resistivity

The filter paper method is an economical, easily accessible, and simple-to-use method to measure total or matric suction over a wide suction range. Difficulty in handling the filter paper can result in inaccurate water content determination of the filter paper leading to poor estimation of the suction. This paper examines the feasibility of using electrical resistivity of the filter paper in the non-contact mode to determine equilibrium time and to infer the total suction. It was shown that for a specific set-up, electrical resistance (ER) can be used in place of electrical resistivity. Relationships between ER and water content of the filter paper and between ER and total suction were first established. Finally, a prototype set-up is used to demonstrate how it can be used to measure the total suction of soil specimens. It was demonstrated that ER of the filter paper can be used to provide a reasonable estimate of total suction greater than 100 kPa with an error between −18 and +10%. Better accuracy can be achieved if each filter paper is calibrated before use.

A Unified Approach for Establishing Soil Water Retention and Volume Change Behavior of Soft Soils

Abstract The assumption of treating the specimen volume as constant while experimentally determining the soil water retention curve (SWRC) of soils is valid only for nonplastic, granular soils. Fine-grained soils usually undergo significant volume change during dewatering and densification, and therefore such an assumption is misleading, even falsifying. The need for developing an easy-to-use lab-scale technique that can enable continuous monitoring of the evolutions in volume, suction, and moisture content of a progressively drying soft soil specimen is evident in the field of characterizing unsaturated soils. Such a method is relevant to establishing SWRC and soil shrinkage curve (SSC) of soft soils that exhibit an appreciable degree of deformation upon subjection to dewatering. To this end, a simple yet improvised method based on the balloon technique incorporating a commercially available high-capacity polymer tensiometer has been proposed to establish SWRC-SSC of soft soils. A comparison between the SWRC and SSC obtained through the proposed method and the conventional methods demonstrated a satisfactory degree of agreement. Densification of the materials realized under the influence of mechanical and hydraulic stresses has been discussed through a comparative analysis between the results from the proposed method and one-dimensional odometer test. For soft soils, the proposed method is particularly appropriate for establishing SWRC in terms of volumetric moisture content and degree of saturation through just a single test.

Experimental Study on the Effect of Freeze—Thaw Cycles on the Mineral Particle Fragmentation and Aggregation with Different Soil Types

The freeze–thaw cycle can change the size and shape of soil particles, that is, cause fragmentation and aggregation of soil mineral particles, thereby affecting the soil structure, which, in turn, affects the soil properties. In addition, the process of soil mineral fragmentation and aggregation, as an event closely related to the cold climate, plays an irreplaceable role in reconstructing the climatic conditions of a certain area and a certain period of time and has important referential significance for the restoration of historical permafrost boundaries and the study of climate change. Therefore, in order to better study the effect of freeze–thaw cycles on the fragmentation and aggregation of soil mineral particles, four soil specimens were selected for this study; the freeze–thaw cycle tests were carried out 0, 3, 6, 9, 50, and 100 times, respectively, and the test results were analyzed. The results of these experiments indicate that (1) after freeze–thaw cycles, the changes in grain-size distribution are different in various soil types, and the changes are mainly concentrated in 0.001–0.1 mm; (2) the coarse particle size particles (sand, silt) can be fragmented into relatively fine-grained particles (silt, clay). The fine-grained particles (clay) cannot undergo fragmentation, and the decrease in clay is due to its aggregation; (3) with the increase in freeze–thaw cycles, the fraction change trend of four specimens is parallel to the x-axis, which means the fragmentation and aggregation of soil mineral particles are in a state of equilibrium or balance; (4) the increase in the Kvar value indicates the change in grain-size distribution, which means aggregation and fragmentation of soil mineral particles. After the 100th cycle, the Kvar value of four specimens is <0.1, which belongs to a low-intensity area; (5) the freeze–thaw cycle will change the type of soil, and after 100 freeze–thaw cycles, the soil type of specimen (H) changes from silty clay loam to silty clay; (6) during the freeze–thaw process, different types of soil have different situations of aggregation and fragmentation.

Post-Cyclic Mechanical Behaviors of Undisturbed Soft Clay with Different Degrees of Reconsolidation

Soft soil is often subjected to cyclic loading such as that imposed during storms, under traffic, or in an earthquake. Furthermore, the cyclic-loading-induced excess pore water pressure can be partially dissipated after cyclic loading. Thus, different reconsolidation processes should be considered. A series of static and dynamic triaxial tests were conducted on undisturbed soft soil to determine the post-cyclic mechanical behavior thereof, such as the variation of undrained shear strength, the development of excess pore water pressure, and the evolution of effective stress path. The effects of consolidated confining pressure, cyclic stress ratio, and degree of reconsolidation were analyzed. Results show that the trend of all stress–strain curves is similar under different conditions. The effect of the degree of reconsolidation is such that, with increasing the degree of reconsolidation, the shear strength is enhanced. Meanwhile, compared with undrained shear strength without cyclic loading, the shear strength after cyclic loading with full reconsolidation is increased. These factors also have a significant effect on the undrained shear strength: the greater both the confining pressure and cyclic stress ratio are, the higher the undrained shear strength. A positive excess pore water pressure is always observed during post-cyclic shearing process, irrespective of different factors. The S-shaped effective stress paths under different test conditions are observed and cross the critical state line. The microstructures of undisturbed soil and post-cyclic specimens with different degrees of reconsolidation were quantitatively investigated. Besides that, the degree of influence of different factors on the post-cyclic undrained strength was analyzed. Based on the test results, the undrained shear strength with cyclic load-history was well predicted by existing models.

Estimating drained cross-anisotropic elastic parameters in saturated clays using the undrained properties

The accurate determination of anisotropic small-strain stiffness properties in natural soil deposits is of crucial importance in many geotechnical and geological engineering analyses. Accordingly, the main objective of this study is to propose an approach for evaluating the drained elastic stiffness parameters in saturated clays using the undrained properties. To attain this objective, by assuming cross-anisotropy in clayey soils, it is shown that two measured anisotropic components of shear moduli and the vertical component of Young's modulus in the undrained conditions possess the main contributions. They were then combined with a series of theoretical equations and empirical assumptions in the literature representing the relationships between the drained and undrained elastic parameters to yield the estimated values for the anisotropic drained Young's moduli. To verify the reliability of the suggested approach, the anisotropic elastic properties of 51 clayey soil specimens from 21 different soil types relating to 15 various sites in 4 countries were collected based on the experimental laboratory tests reported in literature. The anisotropic drained Young's moduli in each specimen were estimated through the proposed technique and then compared with directly measured ones with satisfactory agreement. The findings of this study may serve as the convenient references for economic and precise determination of in-situ elastic stiffness parameters in cohesive soil deposits using the non-invasive seismic surveying.

The effect of particle shape on the deformation and stress reduction of a gravel soil due to wetting

This paper investigates the effect of particle shape on the stress reduction and collapse deformation of gravelly soil using a medium-scale direct shear test apparatus under different relative densities, normal stress, and shear stress levels. A new method based on the Micro-Deval test was introduced to produce sub-angular particles from angular particles. Therefore, two series of soil specimens were obtained with the same rock origin, particle size distribution, and relative density but different particle shapes. In addition to traditional direct shear tests on dry and wet specimens, a specific test procedure was applied to explore the stress reduction and collapse of soil specimens due to wetting. The results of the tests, including shear stress–shear displacement and vertical displacement-shear displacement, were compared. The results showed that the stress reduction and settlement due to wetting increased with vertical and shear stress levels in both types of particle shapes, with higher values in angular particle shapes. The particle breakage of the soil specimens was also studied quantitatively using the change in the particle size distribution before and after the test. It was shown that the wetting of the samples had more impact on the particle breakage in angular gravel than sub-angular gravel, which increased linearly with the normal stress.

Experimental Study on Undrained Shear Properties of Saline Soil under Freeze-Thaw Cycles

The freeze-thaw cycle is an important external factor affecting the hydromechanical characteristics of saline soil in cold regions. Due to the presence of water and salt, it has a greater impact on stability. The construction of various projects, such as ditch fills and road subgrades, has mostly used disturbed soils. Therefore, this article takes remolded saline soil in Qian’an, Jilin Province, China, as the research object to evaluate the action of freeze-thaw cycles on the critical state line, effective stress path, pore water pressure-strain relationship, stress-strain relationship, shear strength index, and other mechanical properties via a freeze-thaw cycle test and a consolidated undrained triaxial shear test (CU). The experimental results show that regardless of whether the soil specimen undergoes a freeze-thaw cycle, its stress-strain relationship shows characteristics of strain hardening, while, as the number of freeze-thaw cycles increases, the shear strength gradually decreases. As both the confining pressure and number of freeze-thaw cycles increase, the pore water pressure increases, as does the pore water pressure coefficient in shear failure. Under the action of freeze-thaw cycles, on the p ′ − q plane of the stress space, the effective stress path gradually moves to the lower left side. Both the effective stress path and the pore water pressure characteristics indicate that the degree of consolidation of the soil specimens continuously decreases as the number of freeze-thaw cycles increases. The position of the critical state line gradually lowers, and the critical state stress ratio decreases. The effective stress strength index can more accurately reflect the comprehensive influence of freeze-thaw cycles and confining pressure on the mechanical characteristics of soils than the total stress strength index. Logistic functions can be used to fit and predict the degradation law of the internal friction angle and cohesion.

Effect of Adding Zeolitic Tuff on Geotechnical Properties of Lime-Stabilized Expansive Soil

This study aims to evaluate experimentally the potential of expansive soil stabilization using different additives: zeolitic tuff (ZT), lime, and a combination of lime and ZT. Four different percentages of ZT (10%, 20%, 25%, and 30%), three percentages of lime (2%, 4%, and 6%), and variable percentages of their combinations were used to stabilize the soil for pavement subbase application. Atterberg limits, pH, compaction, linear shrinkage, swelling, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests were performed on treated and untreated soil specimens at different curing times. Results showed that ZT additives effectively reduced the plasticity, linear shrinkage, and swell potential in addition to increase the maximum dry unit weight, UCS, and CBR. The results of this study were supported by a microstructural analysis using scanning electron microscopy (SEM) associated with the energy-dispersive X-ray spectroscopy (SEM/EDX) technique. It was determined that the UCS and CBR values for the 4% lime stabilized soil increased by 22% and 70%, respectively, after the addition of 25% ZT. Based on evaluation of the results, an optimum mixture of 25% ZT and 4% lime stabilized soil can be used in pavement subbase applications as it achieved the minimum strength target.

Improving engineering characteristics of expansive soils using industry waste as a sustainable application for reuse of bagasse ash

Bagasse ash (BA) is an abundant industrial waste of the sugar-cane refining industry, and its improper disposal can result in a detrimental impact on the environment. In this investigation, BA is considered to assess the possible advantages of its pozzolanic component as a novel sustainable waste application for stabilisation of expansive soils. The engineering characteristics of expansive soils were investigated through an array of laboratory experiments on treated and untreated soil specimens mixed with various contents of additive and cured for different times. A comprehensive investigation of the microstructure evolution of soils after treatment was also undertaken using Fourier transform infrared and scanning electron microscopy techniques. The results revealed that addition of BA, lime, and in particular, combined BA-lime (BAL) remarkably improved the maximum strength (815%), the bearing capacity (9.2 times), the compressibility (83%), and the 100% swell properties of stabilised soils due to rich amorphous silica properties of BA waste that promoted higher pozzolanic reactivities of BAL-soil-mixtures and therefore, enhanced the engineering characteristics of treated soils. The findings showed that a proper combination of bagasse ash waste and lime, as a stabilising additive, can effectively enhance the engineering properties of expansive soil while addressing the environmental impact of BA waste disposal. The industrial waste (BA) can be reused as a cost-effective and green construction material for the benefit of sustainable development of civil infrastructure.

Rheological Properties of Argillaceous Intercalation under the Combination of Static and Intermittent Dynamic Shear Loads

The construction and long-term operation stage of the rock slope with argillaceous interlayer will be subjected to intermittent dynamic loads, such as blasting and earthquake. For the argillaceous interlayer in the rock slope, its rheological properties are not only related to the initial stress state caused by the gravity of the overlying rock mass but also affected by intermittent dynamic loads. In order to investigate the rheological properties of argillaceous intercalation under the combination of static and intermittent dynamic shear loads, the rheological tests of argillic intercalated soil samples under static shear, static and cyclic dynamic shear, and static and intermittent dynamic shear were carried out, and the rheological deformation characteristics of soil samples under different shear conditions were analyzed. The results show that when the soil specimens in the static shear rheological process are disturbed by intermittent dynamic shearing load, the intermittent dynamic disturbances might have no remarkable influence on the rheological deformation of the specimens if the initial static shearing stress and intermittent dynamic shearing stress were comparatively low. However, low-intensity intermittent dynamic disturbances might accelerate the rheological deformation process of the specimens remarkably if the initial static shearing stress state was close to their shearing strength. There was a stress threshold when the soil specimens failed under the static and cycling dynamic shear and static and intermittent dynamic shear, which is determined by the sum of static shear stress and dynamic shear stress peak. For rock slopes controlled by rheological weak structural planes and influenced by long-term blasting vibrations, the transient and long-term dynamic stability should be comprehensively analyzed.

Ecological and human health risks assessment of some polychlorinated biphenyls (PCBs) in surface soils of central and southern parts of city of Tehran, Iran.

The present study was conducted to evaluate the carcinogenic and non-carcinogenic hazards of polychlorinated biphenyls (PCBs) in topsoil across business districts, public green space, cultural and educational areas, and roadside and residential areas in city of Tehran, in 2019. A total of 30 surface urban soil specimens were collected and after preparing them in the laboratory, PCBs contents were determined using gas chromatography-mass spectrometry. Based on the results of data analyses, the median concentrations of PCB18, PCB28, PCB 29, PCB 31, PCB 44, PCB 52, PCB 101, PCB 138, PCB 141, PCB 149, PCB 153, PCB 189 and PCB 194, were found to be 6.81, 0.759, 0.005, 1.75, 2.51, 0.059, 2.31, 3.76, 5.82, 0.599, 0.408, 0.008 and 0.008µg/kg, respectively. Also, the overall daily PCBs intakes via soil ingestion, inhalation and skin contact were 5.48E-04, 1.19E + 00 and 1.62E-04µg/kg, respectively. Thus it was decided that the inhalation of soil could be the main pathway of exposure to PCBs, and that, based on the carcinogenic risk outcomes, children would be more at risk of cancer than adults would. In general, considering that among the studied urban spaces, the contents of PCBs in public green spaces were more than their rates in other areas, and considering that children normally play in the green areas are, it is recommended that special attention be paid to these areas in controlling and removing pollution caused by PCBs in urban areas.

Analysis of Heavy Metals Levels in Locally produced Rice Fumigated with Cypermethrin (Pyrethroid) Pesticide Grown in Auyo Rice Field of Jigawa State

There is a growing public concern over the potential accumulation of heavy metals in agricultural soils owing to rapid urban and industrial development and increasing reliance on agrochemicals in the last several decades. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but elevated heavy metal uptake by crops may also affect food quality and safety. The present study aims to study heavy metal concentrations in rice parts (root, stem, leaf, seed and corresponding soils in the Auyo rice field. Specimens of rice plant parts from different locations in 10 × 10 m were sampled with their corresponding soils. Soil and plant specimens were analysed by using Atomic Absorption spectrometry. It was found that metal concentration in soil was highly variable while the concentration of metals in plants directly depends on the concentration of metal-based pesticide applied. Roots showed the highest metal concentration, followed by leaves, stem and seeds. The physicochemical parameters of the soil from the study area revealed that the pH of the soil sample is within the alkaline range. Similarly, the electrical conductivity was less than 4 (0.51 to 0.65 dSm-1), indicating the presence of soluble salts within average, dissolved Nitrogen at a range of 179.4 to 221 kg/Ha, showing low in nitrogen content, Phosphorus levels in the study region range from 29.00 to 42.33 kg/ha, while potassium level in the soil varies from 126.22 to 250 kg/ha. In general, the soil in the study area was found to be very rich and fertile for the cultivation of rice. The accumulation of some heavy metals in some rice parts may be due to the effects of cypermethrin pesticides.