Original Soil Research Articles

Long-term effects of soft rock amendment on changes of soil aggregate cementing agents of sandy soil by SEM-EDS

Soil aggregates are a crucial constituent of soil and have a significant function in regulating water, nutrients, air, and heat within the soil. The development of soil aggregates is influenced by various factors, including the soil’s parent material and human activities. Understanding the formation and the mechanism of stabilization of soil aggregates is of great significance in the study of soil development, in regulating and managing organic carbon pools in soils, and in promoting soil fertility. In this study, aeolian sandy soil with a low degree of soil development and compound soil formed by combining soft rock and aeolian sandy soil were selected as the research objects. We selected three time points from 0 to 9 years after amendment by soft rock in order to investigate the changes of soil aggregate cementing agents. The shape of soil aggregates in both types of soils was analyzed by environmental scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), which were also used to assess the appearance of soil aggregates and quantify the composition of mineral elements on a cross section of the aggregate. The results show that when the soft rock and the aeolian sandy soil are compounded and mixed, the clay minerals in the soft rock change the microstructure of the original aeolian sandy soil from a single granular barrier to one characterized by a cumulative porous structure, indicating that clay minerals promote soil development and form aggregates with good structural properties. The cementing agents in the compounded soil aggregates are mainly clay minerals, aluminum, iron, and calcium. In comparison to aeolian sandy soils, the presence of iron and calcium in compounded soils is notably elevated. The iron oxides present in compounded soils serve a similar function to “bolts” in the formation of soil aggregates. These findings establish a theoretical foundation for investigating the process of soil aggregate formation and the mechanisms by which cementing agents contribute to their stabilization.

Review on Remediation Technology of Heavy Metal Contaminated Soil

With the development of global social economy, there are also problems of soil heavy metal pollution. It will not only destroy the original soil quality, but also cause harm to our health and affect the growth and development of animals and plants. Therefore, the remediation of soil pollution has become an important research field. This paper expounds the current common soil remediation technology, comprehensively evaluates the corresponding remediation technology, and preliminarily puts forward the development suggestions of soil remediation technology in contaminated sites.

Home-field advantage effects in litter decomposition is largely linked to litter quality

Climate change and associated environmental alterations affect plant communities, potentially decoupling links between plants and their associated soil microbial communities. This may in turn affect processes like litter decomposition, an important function that controls nutrient and carbon cycling as well as many other ecosystem processes. Microbial decomposers have been proposed to specialize, being able to easier decompose litter from its ‘home’ community than litter from other communities, in what is termed the home field advantage (HFA) hypothesis. We report a litter decomposition experiment including four alpine meadow communities spread along a geographical gradient that ranged from the Atlas in Morocco to the Iberian Peninsula to the Swiss Alps. We tested whether litter decomposition rate would differ depending on litter and soil origin, expecting interactions between litter and soil microbial communities to be at the core of responses. We expected to find HFA in all four alpine communities. HFA ranged from very negative to neutral to positive along our geographical gradient, in a variation that could be attributed to the interaction of microbial communities with soil and plant traits, and linked to the relative abundance of microbial groups performing specific functions. Litter decomposition depended on litter quality and on the fungal community, which seemed adapted to deal with poor-quality, recalcitrant litter, leading to HFA. Climate plays a role as well, indirectly through plant community composition. Phyllosphere communities competed with soil communities when in interaction, a fact that may have blurred results of some previous HFA experiments. In summary, there is a clear HFA in systems with low-quality litter that requires a specialised fungal community to maximize decomposition. By contrast, high-quality, easy to decompose litter would be dealt with by any decomposer community, not showing evidence of HFA.

The Bearing Capacity Analysis of Deep Foundation based on In-situ Dynamic Penetration Test Compared to Pile Driving Analyzer (PDA)

On road/ bridge construction, foundation stability analysis is carried out by reviewing the bearing capacity. At the planning stage, this aspect can be calculated based on empirical and numerical methods using In-situ Dynamic Penetration Test data. Meanwhile, at the implementation stage, the bearing capacity results are checked using Pile Driving Analyzer (PDA). Hereinafter, the bearing capacity result in the field is compared with the bearing capacity result at the planning stage whether they are appropriate or not. In this study, the results of bearing capacity based on empirical using Meyerhoff and Schmertmann and numerical methods using MIDAS GTS NX were compared with the results of the PDA test. This study takes an overview of the Semarang – Demak Toll Road Development Project Package 2 STA 16 + 075. The analysis was carried out based on three STA points. The results obtained show that the largest deviation value is when the PDA result is compared with the Schmertmann method, which is 0.59 and the smallest deviation is when comparing PDA with MIDAS 0.03. Both deviations are located on P 133F STA 16+711. This different deviation is due to the ultimate bearing capacity analysis based on empirical equations that only analyze single piles based on the original soil properties, while the MIDAS analysis also considers pile parameters and interface parameters. Moreover, in the PDA test, there are factors of environmental conditions.

Tare Soil Alters the Composition of the Developing Potato Rhizosphere Microbiome

Understanding the factors influencing microbial community composition in the rhizosphere is an important step toward managing the microbiomes of globally important crops such as potato ( Solanum tuberosum). Potato is vegetatively propagated and seed tubers are planted with tare soil, or soil adhering to the tuber surface, from their field of origin. Bulk soil is known to influence rhizosphere microbiome composition but whether tare soil additionally contributes to compositional variation is not known. We tested this hypothesis in a greenhouse experiment where tare soil was removed (or remained intact for controls) prior to planting in either soil from a potato field or soil from a previously uncultivated area next the potato field. We used internal transcribed spacer and 16S metabarcoding to characterize the fungal and bacterial rhizosphere communities of plants grown from the experimental seed tubers. We found that tare soil influenced rhizosphere microbial composition, more strongly for fungi than bacteria. As expected, bulk soil origin explained the greatest amount of variation in the rhizosphere microbiome overall but we found no evidence that the impact of tare soil on microbial community composition differed between bulk soil origins. However, the magnitude of the tare soil effect did depend, in part, on seed tuber origin. Our findings reveal that tare soil explains a significant, though modest, amount of variation in rhizosphere composition, and sets the stage for future work addressing functional consequences for plant health and productivity.

ANALISIS STABILITAS TANAH SUBGRADE PADA PROYEK PEMBANGUNAN JALAN TOL JAKARTA-CIKAMPEK 2 SELATAN PAKET 3

Subgrade soil is the foundation for pavements, both pavements on traffic lanes and shoulders. Thus, the subgrade is the final construction that receives the vehicle load distributed by the pavement. In simple cases, subgrade consists of natural soil without treatment; whereas in other, more common cases, subgrade consists of the original soil in the excavation or the top of the embankment which is compacted. As a land transportation infrastructure, pavement must have a surface that is always flat and rough, so that road users can feel comfortable and safe. Because it is built on subgrade soil, the pavement performance will be greatly influenced by the quality of the subgrade soil. The purpose of this paper is to determine whether the road foundation is sufficiently used with the existing soil, to carry out subgrade improvement and the use of geotextile and geogrid for subgrade improvement The data and information used are primary data from the Jakarta Cikampek 2 Selatan Paket 3 obtained from the results of soil tests in the field. The determination of the geotextile to be used is based on the results of the CBR test and the calculation of the load to be received by the geotextile and will also determine the type of geotextile to be used. The results obtained for the value of T = 23,951 Kn/m, then Geotextile Type GM-150 was used. By using non-woven geotextile as a separator at sta. 35+800 to 36+000 to avoid excessive replacement of soil layer thickness that does not meet specifications (soil with large compression properties), so that in terms of cost and implementation time it is more economical.

PENGARUH PENGGUNAAN ENDOCARP SAWIT UNTUK STABILISASI TANAH LUNAK PEATLAND

During this use Endocarp mostly produced by the oil palm plantation industry. Research is done by mixing Endocarp oil palm that has been sun-dried with maximum dry conditions along with soft clay soil with a content of Endocarp 4%, 6%, and 8%. The sample used in this study is a samples undisturbed , and samples disturbed prepared in the laboratory by mixing clay and Endocarp with a variation of the mixture used is 4%, 6%, and 8% from one bag of clay weighing 2 kg. There is a mix Endocarp the following results were obtained: equal to 1.37 gram/cm3 with a water content of 24.72% (original soil). The CBR value of the mixture Endocarp this study 4%, 6%, 8% obtained the result that the CBR value is mixed Endocarp 4% has the greatest CBR value, which is equal to 7.99% (Unsocked) and 6.69% (socked). The UCT value of the soil will increase in the presence of a mixture Endocarp until mixed Endocarp added by 4% and the UCT value will decrease after the mixture Endocarp above 8% fiber content, maximum UCT value is produced in the mixture Endocarp 4% with a qu value of 0.9295 kg/cm2. The value of the soil shear resistance (su) on the test Vane Shear Test continued to improvement in the mixture Endocarp as much as 4% worth 92 kPa (25 blow condition).

Effect of Organic and Mineral Soil Additives on Asparagus Growth and Productivity in Replant Soils

The repeated cultivation of asparagus in the same field can severely reduce yield. A complex of predominantly microbial causes is suspected. Limited plant development, establishment problems, and yield loss may occur, particularly in light sandy soils. In order to address this replant problem and evaluate alternative cultivation conditions, two asparagus fields were treated with different supplements and were cultivated for 5 years to investigate their impact on yield. The results from the pot trials using soils from these fields are presented, along with the field trial findings. The trials included the incorporation of mushroom substrate (champost), Fimonit (clay mineral), mustard meal (biofumigation), and Micosat F Uno (including arbuscular mycorrhizal fungi, Trichoderma viride, and rhizosphere bacteria species). In the pot trials, the sterilised soil exhibited a growth benefit over the original soil. However, the tested additives had no significant effects in the short period of 8 weeks. At one of the tested field sites, the marketable asparagus yields following champost, Fimonit, biofumigation, and Micosat treatments were 14, 6, 16 and 12% higher than that of the control soil, respectively, but no significant differences in treatment effect were observed in the second test field. Biofumigation using mustard meal and champost was most successful in reducing the impact of replanting on yields.

Iron oxidation coupled with nitrate reduction affects the acetate-assimilating microbial community structure elucidated by stable isotope probing in flooded paddy soil

Acetate is an abundant carbon source that can trigger microbial redox processes in anoxic environments, thereby affecting the microbial community structure, function, and associated element cycling. Here, we investigated the acetate-assimilating microbial community, especially the key microorganisms involved in nitrate-dependent Fe(II) oxidation that are closely associated with soil redox processes in flooded soil. In the present study, DNA-stable isotope probing (DNA-SIP) with labeled acetate (13C) as a carbon source was applied to examine the acetate-assimilating communities associated with nitrate-dependent Fe(II) oxidation. The results showed that NO3− was rapidly reduced in the treatments with NO3− and NO3− + Fe(II). Fe(II) oxidation occurred quickly only in the presence of NO3−. In the treatments with acetate only, the predominant 13C-labeled genera such as Geobacter, Azospira, Azospirillum, Ideonella, and Desulfovibrionia were probably involved in acetate oxidation coupled with the redox processes of NO3−, Fe(III) and SO42− reduction, which are the most important electron acceptors in flooded soils. The addition of NO3− and Fe(II) significantly affected the acetate-assimilating microbial community from the original soil. The enriched genera in 13C heavy fractions were associated with Pseudogulbenkiania, Azospira, Zoogloea, Azoarcus, and Bdellovibrio dominated in the treatments with NO3− and Fe(II). In the treatments with NO3− only, Zoogloea, Azospira, Azoarcus, and Geothrix were the dominant genera. Given the different genera with enrichments in 13C-heavy fractions in different treatments, Zoogloea and Pseudogulbenkiania were identified as key microorganisms associated with NO3− reduction and nitrate-dependent Fe(II) oxidation, respectively. These findings suggest the importance of Zoogloea and Pseudogulbenkiania for C, Fe, and N biogeochemistry and indicate that Fe and N cycling have a great impact on soil biogeochemistry processes.

Role of extreme vertex design approach on the mechanical and morphological behaviour of residual soil composite

This research work reports the usability of binary additive materials known as tile waste dust (TWD) and calcined kaolin (CK) in ameliorating the mechanical response of weak soil. The extreme vertex design (EVD) was adopted for the mixture experimental design and modelling of the mechanical properties of the soil-TWD-CK blend. In the course of this study, a total of fifteen (15) design mixture ingredients’ ratios for water, TWD, CK and soil were formulated. The key mechanical parameters considered in the study showed a considerable rate of improvement to the peak of 42%, 755 kN/m2 and 59% for California bearing ratio, unconfined compressive strength and resistance to loss in strength respectively. The development of EVD-model was achieved with the aid of the experimental derived results and fractions of component combinations through fits statistical evaluation, analysis of variance, diagnostic test, influence statistics and numerical optimization using desirability function to analyze the datasets. In a step further, the non-destructive test explored to assess the microstructural arrangement of the studied soil-additive materials displayed a substantial disparity compared to the corresponding original soil material and this is an indicator of soil improvement. From the geotechnical engineering perspective, this study elucidates the usability of waste residues as environmental friendly and sustainable materials in the field of soil re-engineering.

Modification of a Constitutive Model for Gassy Clay

Gassy clays containing large, discrete gas bubbles are widely spread in deposits in shallow waters. The existence of gas bubbles may impair the original soil structure, resulting in the instability of offshore foundations and the occurrence of submarine landslides. Although gassy clay was found to exhibit different undrained shear behaviors with variations of the initial pore water pressures and initial gas volume fractions, more experimental studies and theoretical interpretations of the relationship between the effective confining pressure and undrained responses are required. A series of undrained triaxial compression tests is conducted to compare the responses of reconstituted gassy and saturated specimens at an effective confining pressure of 200, 400, or 600 kPa. An existing elastoplastic constitutive model based on the critical state is improved by updating its stress-dilatancy function and yield surface. The dilatancy equation proposed has the potential to quantify the effect of gas bubbles on the dilatancy of the soil matrix. The yield surfaces are reproduced reasonably well by optimizing the expressions of shape parameters under a variety of effective confining pressures. The model developed can describe the stress-dilatancy and stress-strain responses of both the gassy and saturated specimens.

Multiparametric analysis for the determination of radon potential areas in buildings on different soils of volcanic origin

The transposition of the European EURATOM directive into the regulations of the different member states of the European Union involved governments making great efforts to define priority action maps against indoor radon exposure in buildings over a short time period. In Spain, the Technical Building Code established 300 Bq/m3 as a reference level and set up a classification of municipalities in which remediation measures should be adopted for radon exposure in buildings. Oceanic volcanic islands, such as the Canary Islands, present high geological heterogeneity in a small space due to their volcanic origin. This variability poses a challenge to the elaboration of radiological risk maps, which makes it necessary to have a high density of data to collect local variations. This paper presents a methodology to obtain accurate radon risk maps based on geological criteria and terrestrial gamma radiation. The predictive efficiency of these maps is statistically verified using indoor radon concentration data measured in buildings. Other radiological variables, which are commonly used as criteria for radon risk prediction found in the literature, were also applied, such as the geogenic radon potential and the activity concentration of natural radioisotopes in soils. The higher resolution of the maps obtained allows for a more detailed classification of radon risk zones in the study area than the current risk maps published in the Spanish building regulations.

Clayshale stabilization using active natural lime to increase the shear strength of soil

Clayshale not used in construction because it is easily weathered when exposed to air and water to reduce the soil shear strength. As a result, this decline can cause geotechnical engineering problems, and clayshale needs stabilization. This study aims to determine the shear strength of clayshale by adding variations of 5%, 8%, and 11% lime. Tests carried out to obtain soil parameters include soil index and engineering properties. Based on laboratory tests, the original clayshale soil has a 33.2% liquid limit, a 6,1% plasticity limit, and a 27,1% plasticity index. Hence, clayshale soils belong to the CL(clay-low plasticity) category based on the USCS. Adding lime variations can increase the specific gravity and the optimum moisture content of the clayshale soils. Still, it can reduce the dry unit weight and the plasticity index value on clayshale soils. The triaxial test on the original clayshale soil sample obtained a cohesion(c) value of 0.20kg/cm2 and friction angle(f) of 6.38°. In contrast, the values of c and f occurred the highest increase from the original clayshale soil with the addition of 8% lime, so lime can be used as an alternative in soil stabilization because it can increase the shear strength of the soil.

Analysis of the handling and preparation of samples in the resonant column and cyclic torsional shear equipment

In many geotechnical applications, the shear modulus G is the one that governs the dynamic behaviour of the soil, and many fields and laboratory methods are focused on calculating it. This is the case of the resonant column and cyclic torsional shear tests, which allow both the modulus G and the damping D to be obtained in different strain ranges. These laboratory tests are carried out in a triaxial cell and in both tests, torsion is applied to the upper part of the specimens, which has allowed new commercial devices to group both techniques in a piece of a single equipment. The combination of the two tests makes it possible to obtain the dynamic properties of the soil over a wide range of strains, 10-4≤γ≤1%.Due to the small strains reached in these tests, less than 1%, the correct preparation of the specimens and their mounting in the triaxial cell are factors of vital importance for the reliability of the test results. In undisturbed samples, the sample should be handled, and the specimen carved with special care, trying not to alter the structure of the original soil. For remoulded clay specimens, static compaction in an external press and subsequent mounting on the triaxial cell pedestal are recommended. Saturation can present difficulties, as in these tests drainage and saturation can only be carried out from the bottom of the specimen. Consolidation times can be long. Sand specimens should be made by placing a mould on the pedestal of the triaxial cell and applying a vacuum. The method of freezing the specimen is discarded due to the long assembly time.

Soil bacterial community composition and diversity respond to soil environment in rooftop agricultural system

The rooftop farm is of increasing interest in urban food production and greening, which operates with less environmental impact than conventional farms. However, the evidence about the bacterial community composition and soil environment in rooftop farm is still insufficient. In this study, three sampling sites (the original soil sample, the soil samples after a seven-year natural cycle, and the soil samples after a seven-year microcirculation system) were selected to study soil properties, bacterial communities, and the relationship between the two in a rooftop farm. Based on high-throughput sequencing, 61 phyla, and 1125 genus were identified in 15 soil samples. Among them, Acidobacteriota and Proteobacteria were the most dominant phyla. At the genus level, microcirculation system increased the relative abundance of Nitrospira. In addition, the co-occurrence network demonstrated that the dominant soil properties to influence bacterial community were total nitrogen and organic matter in rooftop farm. Notably, microcirculation system effectively increased the contents of total nitrogen and total organic carbon by about 2 and 3.5 times, respectively, indicating the effectiveness of microcirculation system in altering rooftop soil and microbial communities. The function predictions of microbial taxa showed that the bacterial function of digestive system and excretory system significantly enriched in microcirculation system. Taken together, the microcirculation system of rooftop farm effectively improved the soil environment and altered bacterial community, which is of considerable application value in building rooftop farms.

Soil Organic Carbon as Response to Reforestation Age and Land Use Changes: A Qualitative Approach to Ecosystem Services

The proper management of soil, in order to improve ecosystem services, requires knowledge of how different fractions of carbon respond to land use/land cover changes. This study aimed to evaluate the responses of total soil organic carbon, and its fractions, to reforestation age and land use changes in an Ultisol in the Posses catchment, a pilot area of the Brazilian program of Payment for Environmental Services, located in Southeastern Brazil. The study was conducted using field plots with various treatments, including native forest, old and young reforestation, well-managed pasture, subsistence farming, degraded pasture, and bare soil. Results showed that soil organic carbon increased with reforestation age and that original soil carbon stocks were restored after eight years of reforestation. Short-time pasture management increased the carbon pool by 10% compared to degraded pasture. The Carbon Management Index (CMI) was able to distinguish the effects of converting degraded pasture to either subsistence farming or bare soil. The CMI is a useful tool for determining the effects of land use/land cover changes, reforestation age, and native forest preservation on soil quality. Adequate management of soil fertilization is an immediate option for restoring the quality of Ultisols under degraded pastures in the Posses sub-basin.

Non-linear response of sediment size characteristics and associated transport patterns to soil structural stability in sheet erosion under field rainfall simulation

Sediment transport patterns (suspension, saltation and rolling) not only depend on flow hydrodynamic characteristics, but also on sediment properties, both of which are largely influenced by soil structural stability. However, how sediment sizes and transport patterns response to original soils over a wide range of structural stability remains unclear. Herein, field plot rainfall simulation experiments on five soils along an increased gradient of structural stability were conducted at two rainfall intensities of 45 and 90 mm h−1 to investigate effective sediment size characteristics and associated transport patterns in sheet erosion. Differing from runoff and sediment yield, sediment sizes were most influenced by soil structural stability (F = 386.9) rather than rainfall intensity (F = 246.7, p < 0.001). Mean weight diameter of sediment (0.16–0.84 mm) and the proportion of coarse particles (>0.25 mm) exhibited a unimodal variation with increased soil structural stability. The effective sediment size distribution shifted from unimodal with the peak at < 0.10 mm for low and high stable soils to bimodal with two peaks at < 0.10 mm and 0.5–1 mm for medium stable soils. Correspondingly, suspension-saltation (>74 %) dominated sediment transport for low and high stable soils, which was determined by fine sized fragments from aggregate breakdown and small flow transport capacity, respectively; while both suspension-saltation (<0.10 mm) and rolling (>0.25 mm) jointly contributed to sediment transport for medium stable soils, which was controlled by the interaction between fragment size and flow transport capacity. Moreover, the positive effect of rainfall intensity on sediment sizes was more remarkable for the medium than for the low and high stable soils. A conceptual model of sediment transport mechanisms in response to soil structural stability is firstly proposed, which merits consideration in the future development of erosion modeling and soil conservation techniques.

The Use of Plastic Sack Fiber and Rice Husk Ash in Increasing the California Bearing Ratio (CBR) Value on the Girisubo Road Section Gunung Kidul Regency

Soil conditions in the Girisubo area, Gunung Kidul Regency, have low soil bearing capacity, so road infrastructure is bumpy and landslides. Therefore, the soil in the area needs to be stabilized and looking for bearing capacity of the soil before use for road subgrades. Clay can be improved by various soil improvement methods, including testing, by mixing plastic sack fiber and rice husk ash. These materials are used based on the high availability of plastic waste and rice husk waste, which are piling up every year. The additional material used was plastic sack fiber with variations of 0.1%, 0.2%, and 0.3% in rice husk ash variations of 0%, 2%, 4%, 6%, and 8% of the dry weight of the soil with the number of test objects 15 pieces. Based on the results, it found the highest CBR value change was obtained in the composition of a mixture of 0.3% plastic sack fiber and 4% rice husk ash of 18.49% and able to increase the percentage of the soil CBR value by 201.50% from the original soil value of 6,13%. Using plastic sack fiber and rice husk ash with the appropriate composition can increase the CBR value and have good quality.

Evolution of terminology in the sphere of organic matter of soil and humus

Goal. To analyze the existing concepts in de­termining the organic matter of the soil and humus and to separate the modern ideas that have developed as a result of a long study of the nature of these substances. Method. Theoretical and analytical. Results. The reasoning of prominent scientists of the 20th century is given, as well as modern researchers regarding the origin, composition, and properties of soil and humus organic matter. Based on an analytical review of scientific publications, the basic terminology of soil organic matter, humus, humus substances, and humification, which has changed over time, is given, and the definition of unified formulations is discussed. The concept of loss (dehumification, dehumus), preservation, and accumulation (sequestration, deposition) of organic matter in soils are considered, and the formulation of separate terms is proposed. Conclusions. At the beginning of the XXI century scientists understand soil organic matter as a system of organic particles of various sizes and biomolecules of plant, animal, and microbiological origin, which consists of plant residues (2–10 mm), solid particles of semi-decomposed organic material (0.053–2 mm), humus (≤0.053 mm) in the form of biomolecules chemically bound to mineral particles, humic and dissolved substances (≤0.45 µm). Humus is a part of the soil organic matter, which in modern literature is called “mineral-associated organic matter”, contained in fractions of dust and clay with a size of ≤0.053 mm.

Remediation performance of As-contaminated water and soil using a novel Fe–Mn bimetallic (oxyhydr)oxide coated on natural magnetite

It is challenging to separate the materials for treating arsenic contamination of soil and water from systems. The natural magnetite covered with Fe-Mn bimetallic (oxyhydr)oxide (Fe-Mn MSM) was effectively created in this study, and its potential use in removing As from water and soil was investigated. Batch adsorption studies showed that the As(V) adsorption on Fe-Mn MSM could achieve equilibrium after 120 min when the initial As(V) concentration was 39.85 mg/L. The calculated maximum adsorption of Fe-Mn MSM for As(V) was 17.94 mg/g at 20 °C. The mechanism of As(V) adsorption was confirmed to be a combination of ligand exchange and electrostatic attraction by the outcomes of FTIR analysis, SEM, and batch adsorption tests. Fe-Mn MSM can also be a successful amendment for cleaning up As-polluted soil. The 5% Fe-Mn MSM treatment group had the lowest exchangeable fraction of As (EX-As) concentration, 0.039 mg/kg (8.3% of initial EX-As), after 40 days. Magnetic separation could be used to quickly and completely recover the used Fe-Mn MSM from the soil. EX-As was present in higher concentrations on Fe-Mn MSM than that of the original soil. As a result, this work offers a strategy that may be put into practice to cheaply remove As from soil and water while also encouraging the reuse of natural magnetite.