Soil Systems

1 pages, 177 KiB

Open AccessCorrection

Correction: Szabó-Szöllösi et al. Evaluation of Native Festuca Taxa for Sustainable Application in Urban Environments: Their Characteristics, Ornamental Value, and Germination in Different Growing Media. Soil Syst. 2024, 8, 99

by Tünde Szabó-Szöllösi, Éva Horváthné Baracsi, Péter Csontos, László Papp, Szilvia Kisvarga, László Orlóci, Judit Házi, Zoltán Kende, Dénes Saláta, Márta Fuchs, Judit Rita Keleti, Ákos Tarnawa, Katalin Rusvai and Károly Penksza

Soil Syst. 2024, 8(4), 129; https://doi.org/10.3390/soilsystems8040129 - 9 Dec 2024

Abstract

In the published publication [...] Full article

16 pages, 8780 KiB

Open AccessArticle

Soil Mapping of Small Fields with Limited Number of Samples by Coupling EMI and NIR Spectroscopy

by Leonardo Pace, Simone Priori, Monica Zanini and Valerio Cristofori

Soil Syst. 2024, 8(4), 128; https://doi.org/10.3390/soilsystems8040128 - 7 Dec 2024

Abstract

Precision agriculture relies on highly detailed soil maps to optimize resource use. Proximal sensing methods, such as EMI, require a certain number of soil samples and laboratory analysis to interpolate the characteristics of the soil. NIR diffuse reflectance spectroscopy offers a rapid, low-cost [...] Read more.

Precision agriculture relies on highly detailed soil maps to optimize resource use. Proximal sensing methods, such as EMI, require a certain number of soil samples and laboratory analysis to interpolate the characteristics of the soil. NIR diffuse reflectance spectroscopy offers a rapid, low-cost alternative that increases datapoints and map accuracy. This study tests and optimizes a methodology for high-detail soil mapping in a 2.5 ha hazelnut grove in Grosseto, Southern Tuscany, Italy, using both EMI sensors (GF Mini Explorer, Brno, Czech Republic) and a handheld NIR spectrometer (Neospectra Scanner, Si-Ware Systems, Menlo Park, CA, USA). In addition to two profiles selected by clustering, another 35 topsoil augerings (0–30 cm) were added. Laboratory analyses were performed on only five samples (two profiles + three samples from the augerings). Partial least square regression (PLSR) with a national spectral library, augmented by the five local samples, predicted clay, sand, organic carbon (SOC), total nitrogen (TN), and cation exchange capacity (CEC). The 37 predicted datapoints were used for spatial interpolation, using the ECa map, elevation, and DEM derivatives as covariates. Kriging with external drift (KED) was used to spatialize the results. The errors of the predictive maps were calculated using five additional validation points analyzed by conventional methods. The validation showed good accuracy of the predictive maps, particularly for SOC and TN. Full article

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17 pages, 4336 KiB

Open AccessArticle

Sorption and Phase Associations of Chromate and Vanadate with Two Contrasting North Carolina Saprolites

by Fatai O. Balogun, Hannah R. Peel, Robert E. Austin, Ibrahim G. Okunlola, David S. Vinson, Owen W. Duckworth and Matthew L. Polizzotto

Soil Syst. 2024, 8(4), 127; https://doi.org/10.3390/soilsystems8040127 - 3 Dec 2024

Abstract

Geogenic chromium (Cr) and vanadium (V) contamination of groundwater in the Piedmont region of North Carolina poses threats to public health. These contaminants are naturally derived from saprolite and aquifer materials, but geochemical variability in these materials makes it difficult to predict specific [...] Read more.

Geogenic chromium (Cr) and vanadium (V) contamination of groundwater in the Piedmont region of North Carolina poses threats to public health. These contaminants are naturally derived from saprolite and aquifer materials, but geochemical variability in these materials makes it difficult to predict specific risks of Cr and V in well water. The objectives of this study were to (1) determine host phases of Cr and V in representative subsurface materials; (2) characterize contaminant binding parameters of chemically variable saprolites; and (3) examine the influence of saprolite chemistry on contaminant sorption, speciation, and phase associations. Isotherm experiments revealed that saprolite samples sorbed roughly an order of magnitude more V than Cr. Chemical extractions and synchrotron-based X-ray fluorescence showed that substantial Cr and V were bound with metal oxide/oxyhydroxides in native and Cr-and V-sorbed saprolites; however, electrostatically bound fractions were also present, representing potentially important sources of groundwater contamination. X-ray absorption-near-edge-structure spectroscopy indicated that sorbed Cr was found as reduced Cr(III), whereas sorbed V was dominated by the oxidized V(V) and intermediate V(IV) species. Results from this study could be used to help parameterize mechanistic models and improve prediction of the Cr and V contamination potential of shallow aquifers. Full article

(This article belongs to the Special Issue Adsorption Processes in Soils and Sediments)

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11 pages, 1311 KiB

Open AccessArticle

Influence of Annual Ryegrass (Lolium multiflorum) as Cover Crop on Soil Water Dynamics in Fragipan Soils of Southern Illinois, USA

by Amitava Chatterjee, Dana L. Dinnes, Daniel C. Olk and Peter L. O’Brien

Soil Syst. 2024, 8(4), 126; https://doi.org/10.3390/soilsystems8040126 - 3 Dec 2024

Abstract

Fragipans are dense subsurface soil layers that severely restrict root penetration and water movement. The presence of shallow fragipan horizons limits row crop production. We hypothesized that the roots of cover crop might improve soil physiochemical properties and biological activity, facilitating drainage and [...] Read more.

Fragipans are dense subsurface soil layers that severely restrict root penetration and water movement. The presence of shallow fragipan horizons limits row crop production. We hypothesized that the roots of cover crop might improve soil physiochemical properties and biological activity, facilitating drainage and increasing effective soil depth for greater long-term soil water storage. To evaluate annual ryegrass as one component of a cover crop (CC) mix for promoting the characteristics and distribution of soil water, on-farm studies were conducted at Marion and Springerton in southern Illinois, USA. Soil samples were collected at 15 cm increments to 60 cm (Marion) and 90 cm (Springerton) depths during the fall of 2022. Both sites had low total soil carbon and nitrogen contents and acidic soil pH (≤6.4). A soil water retention curve was fitted using the van Genuchten equation. At Springerton, the CC treatment increased saturated (thetaS) and residual (thetaR) soil water contents above those of the no cover crop (NCC) at the 60–75 cm and 75–90 cm depths. Changes in volumetric soil water content were measured using a multi-depth soil water sensor for the Springerton site during late July to early August of the soybean growing phase of 2022; NCC had higher soil water than CC within the 0–15 cm depth, but CC had higher soil water than NCC at the 30–45 cm depth. These findings indicate that cover crop mix has the potential to improve soil water movement for soils with restrictive subsoil horizon, possibly through reducing the soil hydraulic gradient between the surface and restrictive subsurface soil layers. Full article

(This article belongs to the Special Issue Land Use and Management on Soil Properties and Processes)

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26 pages, 14774 KiB

Open AccessArticle

Assessing the Global Sensitivity of RUSLE Factors: A Case Study of Southern Bahia, Brazil

by Mathurin François, Camila A. Gordon, Ulisses Costa de Oliveira, Alain N. Rousseau and Eduardo Mariano-Neto

Soil Syst. 2024, 8(4), 125; https://doi.org/10.3390/soilsystems8040125 - 2 Dec 2024

Abstract

Global sensitivity analysis (GSA) of the revised universal soil loss equation (RUSLE) factors is in its infancy but is crucial to rank the importance of each factor in terms of its non-linear impact on the soil erosion rate. Hence, the goal of this [...] Read more.

Global sensitivity analysis (GSA) of the revised universal soil loss equation (RUSLE) factors is in its infancy but is crucial to rank the importance of each factor in terms of its non-linear impact on the soil erosion rate. Hence, the goal of this study was to perform a GSA of each factor of RUSLE for a soil erosion assessment in southern Bahia, Brazil. To meet this goal, three non-linear topographic factor (LS factor) equations alternately implemented in RUSLE, coupled with geographic information system (GIS) software and a variogram analysis of the response surfaces (VARSs), were used. The results showed that the average soil erosion rate in the Pardo River basin was 25.02 t/ha/yr. In addition, the GSA analysis showed that the slope angle which is associated with the LS factor was the most sensitive parameter, followed by the cover management factor (C factor) and the support practices factor (P factor) (CP factors), the specific catchment area (SCA), the sheet erosion (m), the erodibility factor (K factor), the rill (n), and the erosivity factor (R factor). The novelty of this work is that the values of parameters m and n of the LS factor can substantially affect this factor and, thus, the soil loss estimation. Full article

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12 pages, 2585 KiB

Open AccessViewpoint

The Reduction of Nitrogen Fertilizer Rate Shifted Soil Bacterial Community Structure in Rice Paddies

by Xiaoqing Qian, Shifan Xie, Rui Hu, Wenhui Zhao, Junfei Gu, Wujian Huang and Fulei Xu

Soil Syst. 2024, 8(4), 124; https://doi.org/10.3390/soilsystems8040124 - 2 Dec 2024

Abstract

In order to achieve reasonable yield while keeping environmental risks low, nitrogen fertilizer reduction has been adopted for in rice cultivation. The response of the soil microbial community structure to this management is not fully understood. In this study, the treatments comprising conventional [...] Read more.

In order to achieve reasonable yield while keeping environmental risks low, nitrogen fertilizer reduction has been adopted for in rice cultivation. The response of the soil microbial community structure to this management is not fully understood. In this study, the treatments comprising conventional farming practices (330 kg ha⁻¹), reduced N application (270 kg ha⁻¹ and 300 kg ha⁻¹, respectively), and a control without N application were set up in order to reveal the effects of N application rate on the soil microbial community composition in rice paddies. It was discovered that Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi represented the most abundant bacterial phyla in all samples. The assembly of the soil bacterial community differed among the treatments, with NH₄⁺-N, available phosphorus (AP), and organic matter (OM) as key drivers. The reduction of N application by 20% decreased soil NO₃⁻ up to 32% and increased the abundance of the total functional pathways, especially those associated with carbon fixation, N, S, and CH₄ metabolism, whereas N reduction by 10% increase soil N accumulation and soil bacterial richness. In summary, a reduction of N fertilizer by up to 20% compared to the amount used in traditional practices could most effectively regulate the soil bacterial community composition and increase the predicted functional groups associated with N transformation, while maintaining lower soil nitrogen contents. Full article

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15 pages, 2492 KiB

Open AccessArticle

Distribution and In Vitro Bioaccessibility of Potentially Toxic Metals in Soils at Select Urban Parks at Eastern Canadian Cities

by Matt Dodd, Abdurrazzaq Durojaiye and Julia Dupuis

Soil Syst. 2024, 8(4), 123; https://doi.org/10.3390/soilsystems8040123 - 27 Nov 2024

Abstract

This study investigated the human health risks associated with exposure to potentially toxic metals, including arsenic, barium, cadmium, chromium, cobalt, copper, lead, nickel, and zinc, at select parks in Eastern Canadian cities. Except for arsenic in Halifax, the mean metal concentrations in the [...] Read more.

This study investigated the human health risks associated with exposure to potentially toxic metals, including arsenic, barium, cadmium, chromium, cobalt, copper, lead, nickel, and zinc, at select parks in Eastern Canadian cities. Except for arsenic in Halifax, the mean metal concentrations in the cities, including Saint John, Fredericton, Ottawa, Toronto, London, Windsor, Woodstock, Kitchener, Guelph, Chatham, and Montreal, were below the Canadian Council of Ministers of Environment soil quality guideline for parkland use. Metal distribution reflected either the regional natural-occurring concentrations or anthropogenic sources such as industrial activities, historical land use, and heavy traffic corridors. In vitro bioaccessibility values were variable and in the order chromium < nickel < cobalt < arsenic < zinc < copper < lead < cadmium. The risk associated with incidental soil ingestion for children, incorporating bioaccessibility, indicated unacceptable levels of non-carcinogenic effects for 6 out of the 101 samples analyzed. For adults, unacceptable non-carcinogenic effects were noted for only one sample. Lead was the leading contributor to the non-carcinogenic risk. Carcinogenic risk for arsenic was limited to two samples. The overall risks associated with exposure to metals in soils in most of the parks studied were deemed low except for arsenic and lead at a few parks. Full article

(This article belongs to the Special Issue Research on Heavy Metals in Soils and Sediments)

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8 pages, 210 KiB

Open AccessArticle

Short-Term Effects of Cover Crops and Tillage Management on Soil Physical Properties on Silt Loam Soil

by David Scott Patton, Vern Steven Green, Dennis Keith Morris and Calvin R. Shumway

Soil Syst. 2024, 8(4), 122; https://doi.org/10.3390/soilsystems8040122 - 26 Nov 2024

Abstract

Silt loam soils in the mid-southern United States are prone to soil erosion, crusting, and general soil degradation. A field experiment was established at three field sites in northeast Arkansas to evaluate the effect of cover crop and tillage management on cash crop [...] Read more.

Silt loam soils in the mid-southern United States are prone to soil erosion, crusting, and general soil degradation. A field experiment was established at three field sites in northeast Arkansas to evaluate the effect of cover crop and tillage management on cash crop yield and the physical properties of soil health, specifically infiltration rate and aggregate stability. Cover crop management included cereal rye, wheat and crimson clover, and a winter fallow. Tillage management included tillage and no-tillage. During the two-year study, yield was not significantly influenced by different tillage treatments. The cover crop treatment had greater yield than the no-cover crop treatment (5091 vs. 4264 kg ha⁻¹) at one site in one of the years. Water infiltration was significantly improved with cover crops compared to with no-cover crops, with a 52% and 64% increase at Walcott and Magnolia, respectively. Soil aggregate stability was significantly improved with no-tillage as compared with tillage in both years at Walcott, with a 16% and 58% increase in 2015 and 2016, respectively. Both cover crop and tillage management can have significant impacts on soil physical properties in a short period of time. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

15 pages, 3560 KiB

Open AccessArticle

The Effects of the Long-Term Application of Different Nitrogen Fertilizers on Brown Earth Fertility Indices and Fungal Communities

by Hui Li, Zishu Cai, Jiubo Pei, Mengmeng Wang, Siyin Wang, Yao Zhang and Yuwei Liu

Soil Syst. 2024, 8(4), 121; https://doi.org/10.3390/soilsystems8040121 - 21 Nov 2024

Abstract

Soil fungi play a crucial role in soil microbes, the composition and variety of whose communities can be altered due to nitrogen constraints, thereby affecting the plant’s development. This study aimed to investigate the relationship between the composition of soil fungi communities, fertility [...] Read more.

Soil fungi play a crucial role in soil microbes, the composition and variety of whose communities can be altered due to nitrogen constraints, thereby affecting the plant’s development. This study aimed to investigate the relationship between the composition of soil fungi communities, fertility index, and the structure of soil fungal communities under varying nitrogen fertilizer conditions, using a long-term positioning test on the brown earth of Northeast China. It examined the impact of 31 years of applying of no fertilizer (CK, 0 kg N hm⁻² a⁻¹), the single application of inorganic fertilizer (N₂, urea 135 kg N hm⁻² a⁻¹; N₄, urea 270 kg N hm⁻²·a⁻¹), the single application of organic fertilizer (M₄, pig housing fertilizer 270 kg N hm⁻² a⁻¹), and mixed nitrogen fertilizer (M₂N₂, urea 135 N hm⁻² a⁻¹ + pig housing fertilizer 135 kg N hm⁻² a⁻¹) on the fertility index and fungal community structure of brown earth. The findings indicated the following: Long-term non-fertilization and the single application of chemical nitrogen fertilizer reduced the soil pH value and increased the soil bulk density. The application of organic fertilizer reduced soil bulk density and slowed down the reduction of soil fungal richness caused by nitrogen fertilizer application. The long-term application of different nitrogen fertilizers did not alter the dominant fungal phylum, showing that the dominant phylum in all treatments was Ascomycota. The pH, organic matter, total phosphorus, available phosphorus, total nitrogen, alkaline nitrogen, and available potassium were the main soil factors affecting the structural diversity of soil fungal communities. Total phosphorus explained the greatest differences in soil fungal communities. Full article

(This article belongs to the Special Issue Advances in Fertilizer Technologies and Use to Improve Nutrient Efficiency and Minimize Environmental Impacts)

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14 pages, 1995 KiB

Open AccessArticle

Landscape–Geochemical Assessment of Content of Potentially Toxic Trace Elements in Arctic Soils

by Evgeny Lodygin, Ivan Alekseev and Boris Nesterov

Soil Syst. 2024, 8(4), 120; https://doi.org/10.3390/soilsystems8040120 - 18 Nov 2024

Abstract

The importance of research to assess the impact of potentially toxic trace elements (PTEs) on the environment and the importance of environmental monitoring, taking into account the natural variability of soil properties, shaped the aim of our study: to determine the background concentrations [...] Read more.

The importance of research to assess the impact of potentially toxic trace elements (PTEs) on the environment and the importance of environmental monitoring, taking into account the natural variability of soil properties, shaped the aim of our study: to determine the background concentrations of PTEs in different soil profiles in the European Northeast, specifically in the Republic of Komi in Russia, taking into account the landscape and geochemical characteristics of the area. We analysed 173 soil samples from five main soil subtypes. The acid soluble forms of PTEs (Cu, Pb, Zn, Ni, Cd and Mn) were measured using an atomic emission spectrometer. We developed a database of PTE contents and created distribution maps for the Komi Republic using GIS technologies. The study found that PTE levels in soils from accumulative landscapes (such as depressions and floodplains) were generally higher than those in soils from eluvial landscapes (interfluves). We identified correlations between the levels of different PTEs and certain soil properties, providing insights into the biogeochemical migration patterns of these elements. The differentiation of PTEs in soil profiles was more pronounced in loamy automorphic soils and less so in sandy semi-hydromorphic and hydromorphic soils. Most soils, except floodplain soils, showed a clear eluvial–illuvial pattern of PTE distribution within the mineral soil profile, whereas floodplain soils showed a more uniform PTE distribution. The results of this study are useful for assessing the contamination levels of these soil types in high-latitude regions. Full article

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15 pages, 1906 KiB

Open AccessArticle

Bacterial Communities Nodulating Lupinus cosentinii Gus. and Their Inputs in the Worldwide Phylogeography of Lupine Endosymbionts

by Mokhtar Rejili, Mohamed Ali Benabderrahim and Mohamed Mars

Soil Syst. 2024, 8(4), 119; https://doi.org/10.3390/soilsystems8040119 - 17 Nov 2024

Abstract

Genetic variability in bacterial populations that nodulate Lupinus cosentinii in Tunisia was investigated. Phylogenetic studies of 40 isolates using recA partial sequences categorized them into three clusters within the Bradyrhizobium genus. Twenty-three strains selected from the three clusters were thoroughly examined through housekeeping [...] Read more.

Genetic variability in bacterial populations that nodulate Lupinus cosentinii in Tunisia was investigated. Phylogenetic studies of 40 isolates using recA partial sequences categorized them into three clusters within the Bradyrhizobium genus. Twenty-three strains selected from the three clusters were thoroughly examined through housekeeping genes (recA, glnII and rpoB) multilocus sequence analysis (MLSA). Our results showed that 23 representative strains were distributed in five distinct clusters, with 13 strains belonging to Bradyrhizobium canariense BTA-1^T/Bradyrhizobium lupini USDA3051^T (10 strains) and Bradyrhizobium hipponense aSej3^T (three strains) lineages. Interestingly, eight strains occupied a separate position and could belong to two putative novel Bradyrhizobium species. The nodC phylogeny placed the 23 strains within three symbiovars: genistearum (19 strains), lupini (two strains) and, for the first time, the symbiovar cyanophyllae (two strains). Based on the worldwide phylogeography of rhizobial symbionts nodulating lupine (14 species), our results reported that eight species occurred in more than one continent, and six species were specific for one continent, e.g., Bradyrhizobium rifense, Bradyrhizobium diazoefficiens, Phyllobacterium sp. and Devosia sp. were specific to the African continent, the Bradyrhizobium iriomotense/Bradyrhizobium stylosanthis group to America, and Bradyrhizobium valentinum to the European continent. Full article

(This article belongs to the Special Issue Microbial Community Structure and Function in Soils)

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14 pages, 4518 KiB

Open AccessArticle

Influence of Soil Texture on Carbon Stocks in Deciduous and Coniferous Forest Biomass in the Forest-Steppe Zone of Oka–Don Plain

by Sergey Sheshnitsan, Gennadiy Odnoralov, Elena Tikhonova, Nadezhda Gorbunova, Tatiana Sheshnitsan, Otilia Cristina Murariu and Gianluca Caruso

Soil Syst. 2024, 8(4), 118; https://doi.org/10.3390/soilsystems8040118 - 17 Nov 2024

Abstract

Forests play a crucial role in climate change mitigation by acting as a carbon sink. Understanding the influence of soil properties on carbon stocks in forests is essential for developing effective forest management strategies. The aim of the study was to assess the [...] Read more.

Forests play a crucial role in climate change mitigation by acting as a carbon sink. Understanding the influence of soil properties on carbon stocks in forests is essential for developing effective forest management strategies. The aim of the study was to assess the impact of soil texture on carbon stocks in the biomass of deciduous and coniferous tree stands of a forest-steppe ecotone. Soil samples were collected from 55 soil pits, and forest inventory data were obtained from eight permanent sample plots. The results showed that the distribution of mechanical particles in soils, particularly the stocks of silt and clay, significantly influenced the accumulation of carbon in tree stands. The stock of silt and clay was shown to increase with an increase in the diversity of tree species in forests and carbon stocks in forest stands. While soil organic carbon stocks did not exhibit a clear relationship with tree stand carbon stocks, a strong positive correlation (r = 0.802, p < 0.05) was found between the stocks of fine particles in the 2 m root-inhabited soil layer and the carbon stocks in tree biomass. The study provides a classification of forest types based on soil texture, which can facilitate differentiated forest management strategies for enhancing the carbon sequestration potential of forest ecosystems in the forest-steppe zone. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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16 pages, 2702 KiB

Open AccessArticle

Immobilization of Heavy Metals in Biochar Derived from Biosolids: Effect of Temperature and Carrier Gas

by Shefali Aktar, Md Afzal Hossain, Kalpit Shah, Ana Mendez, Cícero Célio de Figueiredo, Gabriel Gasco and Jorge Paz-Ferreiro

Soil Syst. 2024, 8(4), 117; https://doi.org/10.3390/soilsystems8040117 - 15 Nov 2024

Abstract

Slow pyrolysis was carried out in biosolids under three different temperatures (400, 500 and 600 °C) and two different carrier gases (CO₂ and N₂) on a fluidized bed reactor. The total concentration, chemical fractionation, and plant availability of the heavy [...] Read more.

Slow pyrolysis was carried out in biosolids under three different temperatures (400, 500 and 600 °C) and two different carrier gases (CO₂ and N₂) on a fluidized bed reactor. The total concentration, chemical fractionation, and plant availability of the heavy metals in biochar were assessed by standard methods. The total concentration of Fe, Zn, Cu, Mn, Cr, Ni and Pb increased with the conversion of biosolids to biochar and with increasing pyrolysis temperature. The community’s Bureau of Reference (BCR) sequential extraction identified the migration of metals from toxic and bioavailable to potentially stable available or non-available forms at higher pyrolysis temperatures. Diethylenetriamine penta-acetic acid (DTPA)-extractable metals (Cu, Zn, Cd, Cu, Fe and Pb) were significantly lower in biochar compared to biosolids. By replacing N₂ with CO₂, the total metal concentration of heavy metals was significantly different for Mn, Ni, Cd, Pb and As. There were larger amounts of metals in the residual and oxidizable fractions compared to when N₂ was used as a carrier gas. Consequently, the biochar produced at higher temperatures (500 and 600 °C) in the N₂ environment exhibited lower potential ecological risks than in CO₂ environments (69.94 and 52.16, respectively, compared to values from 75.95 to 151.38 for biochars prepared in N₂). Overall, the results suggest that the higher temperature biochar can support obtaining environmentally safe biochar and can be effective in attenuating the ecological risks of biosolids. Full article

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15 pages, 2868 KiB

Open AccessArticle

Adsorption of Arsenic and Cadmium on Biodegradable and Non-Biodegradable Microplastics in Soil: Comparison Based on Batch Experiment

by Zaw Min Han, Sartaj Ahmad Bhat, Shiamita Kusuma Dewi, Yongfen Wei and Fusheng Li

Soil Syst. 2024, 8(4), 116; https://doi.org/10.3390/soilsystems8040116 - 12 Nov 2024

Abstract

In the present study, the adsorption of arsenic(V) and cadmium(II) onto microplastics from poly(butylene succinate-co-butylene adipate) (PBSA) and low-density polyethylene (LDPE) plastic mulch films was investigated through batch experiment. The surface morphology and elemental composition of soil and microplastics were analyzed with scanning [...] Read more.

In the present study, the adsorption of arsenic(V) and cadmium(II) onto microplastics from poly(butylene succinate-co-butylene adipate) (PBSA) and low-density polyethylene (LDPE) plastic mulch films was investigated through batch experiment. The surface morphology and elemental composition of soil and microplastics were analyzed with scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier-transform infrared (FTIR) spectroscopy. The results show that the adsorption of As(V) and Cd(II) on microplastics led to surfaces with coarseness and more cracks, and many small particles. Under the conditions added with 100 pieces of microplastic, PBSA enhanced the adsorption capacity of As(V) (from 0.43 to 0.49 mg/g), and LDPE increased the adsorption of Cd(II) (from 0.174 to 0.176 mg/g) due to the “superimposed effect” caused by hydrogen bonds. Conversely, LDPE reduced the adsorption of As(V) (from 0.44 to 0.40 mg/g) due to a “dilution effect” of PE. Particularly, PBSA exhibited an insignificant effect on the adsorption of Cd(II) in soil during the present study. Overall, our findings provide new insights into the impacts of microplastics on the fate and behavior of heavy metals in the soil system. Full article

(This article belongs to the Special Issue Research on Heavy Metals in Soils and Sediments)

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17 pages, 2653 KiB

Open AccessArticle

Soil Dynamics in Carbon, Nitrogen, and Enzyme Activity Under Maize–Green Manure Cropping Sequences

by Cassio Hamilton Abreu-Junior, Wanderley José de Melo, Roberto Alves de Oliveira, Paulo Henrique Silveira Cardoso, Raíssa de Araujo Dantas, Rodrigo Nogueira de Sousa, Dalila Lopes da Silva, Thiago Assis Rodrigues Nogueira, Arun Dilipkumar Jani, Gian Franco Capra and Gabriel Maurício Peruca de Melo

Soil Syst. 2024, 8(4), 115; https://doi.org/10.3390/soilsystems8040115 - 12 Nov 2024

Abstract

The diversification of cropping sequences has a positive impact on soil organic carbon, while improving nutrient cycling and crop yields. The objective of this research was to assess amylase, cellulase, C and N dynamics, and maize yield on a low fertility oxisol in [...] Read more.

The diversification of cropping sequences has a positive impact on soil organic carbon, while improving nutrient cycling and crop yields. The objective of this research was to assess amylase, cellulase, C and N dynamics, and maize yield on a low fertility oxisol in the Brazilian Cerrado. The experiment was conducted under field conditions during three maize crop succession cycles. The treatments consisted of cultivating maize during the summer, after sorghum and lablab cropped as green manure and fallow during the winter. Higher maize yields were achieved by sorghum–maize succession compared to monocropping, due to higher N fertilizer and biomass inputs to topsoil. Sorghum–maize succession also provided a higher proportion of stable C and N compared to other successions. Maize yields declined as tropical soil fertility intrinsically decreased along three crops succession cycles. Cellulase activity decreased over time, whereas amylase activity increased as the plant residues were already in advanced stages of decomposition. The sorghum–maize crop succession stood out compared to lablab and fallow as it provided the highest maize yields, while maintaining higher C and N levels, and amylase activity. This better performance was likely due to larger amounts of incorporated biomass and better mineral N fertilizer management. Full article

(This article belongs to the Topic Carbon and Nitrogen Cycling in Agro-Ecosystems and Other Anthropogenically Maintained Ecosystems)

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30 pages, 3426 KiB

Open AccessArticle

Evaluation of Industrial Hemp Cultivar and Biochar Rate to Remediate Heavy-Metal-Contaminated Soil from the Tar Creek Superfund Site, USA

by Dietrich V. Thurston, Kristofor R. Brye, David M. Miller, Philip A. Moore, Jr., Donald M. Johnson and Mike Richardson

Soil Syst. 2024, 8(4), 114; https://doi.org/10.3390/soilsystems8040114 - 8 Nov 2024

Cited by 1

Abstract

Soil contamination by cadmium (Cd), lead (Pb), and zinc (Zn) at the Tar Creek superfund site in northeast Oklahoma, United States, remains a threat to the environment and local ecosystem. Phytoremediation with industrial hemp (Cannabis sativa L.) and the use of biochar [...] Read more.

Soil contamination by cadmium (Cd), lead (Pb), and zinc (Zn) at the Tar Creek superfund site in northeast Oklahoma, United States, remains a threat to the environment and local ecosystem. Phytoremediation with industrial hemp (Cannabis sativa L.) and the use of biochar (BC) have been independently shown to be effective methods to remediate heavy-metal-contaminated soils. The objective of this greenhouse study was to evaluate the effects of industrial hemp cultivar (‘Carmagnola’ and ‘Jinma’), biochar rate (0, 2, 5, and 10% by volume), soil contamination level (low, medium, and high), and their interactions on above- (AG) and belowground dry matter (DM) and AG tissue concentrations, as well as uptakes of Cd, Pb, and Zn after 90 days of growth in naturally contaminated soils from the Tar Creek superfund site. Aboveground DM was the largest (p < 0.01) in the low- (0.06 g cm⁻²) and smallest in the high-contaminated soil (0.03 g cm⁻²), and was unaffected (p > 0.05) by cultivar or BC rate. Averaged across BC rates, AG tissue Pb and Zn concentrations from the high-’Carmagnola’ and -’Jinma’ combinations were at least 2.4 times greater than from the other four soil–cultivar combinations. Averaged across cultivars, AG tissue Pb uptake in the high-5 and high-10% BC combinations were at least 2.7 times greater than in the high-0 and high-5% BC combinations, which did not differ. The results indicated that both ‘Carmagnola’ and ‘Jinma’ may be suitable choices for phytoremediation of mixed Cd-, Pb-, and Zn-contaminated soil when grown in combination with 5 or 10% (v/v) BC. Full article

(This article belongs to the Special Issue Soil Bioremediation)

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28 pages, 10086 KiB

Open AccessArticle

Spatial Variability in the Speciation of Lead (Pb) and Other Metals Across Urban Lawns Is Linked to Post-Deposition Weathering Reactions

by Chukwudi E. Nwoko, David M. Singer, Allyson C. Tessin, Rachel Izworski and Chloe Heestand

Soil Syst. 2024, 8(4), 113; https://doi.org/10.3390/soilsystems8040113 - 6 Nov 2024

Abstract

The historical use of lead (Pb) poses ongoing health risks via exposure to contaminated urban soils. However, there is limited information about heterogeneity in Pb speciation and distribution at the house lot scale. This study determined highly spatially resolved Pb and other metal [...] Read more.

The historical use of lead (Pb) poses ongoing health risks via exposure to contaminated urban soils. However, there is limited information about heterogeneity in Pb speciation and distribution at the house lot scale. This study determined highly spatially resolved Pb and other metal speciation along horizontal transects and vertical soil cores from three homes in the Akron, Ohio (USA) municipal. Solid phase characterization was coupled with a sequential extraction protocol to determine operationally defined speciation (exchangeable (M_EX), reducible (M_RED), oxidizable (M_OX), and residual (M_RES)). Lead and Zn were strongly correlated across all fractions (R² = 0.92). Total extractable Pb and Zn were found in low weight percent concentrations nearest to the homes, and speciation was dominated by M_EX and M_RED. High Pb in the M_EX fraction was correlated with the presence of Pb-bearing paint chips in the soil. Lead in the M_EX fraction in soils near the homes decreased with increasing time due to exterior renovations coupled with increases in Pb and Zn in the M_RED fraction. These results suggest that homes are the dominant source of Pb and Zn due to the weathering of exterior surfaces and highlight the acute risk of exposure to more labile Pb immediately following exterior renovations and damage to home exteriors in areas of older housing stock. Full article

(This article belongs to the Special Issue Research on Heavy Metals in Soils and Sediments)

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15 pages, 1210 KiB

Open AccessArticle

Cultivable Rhizosphere Microbial Community Structure in the Yaqui Valley’s Agroecosystems

by Valeria Valenzuela Ruiz, Edgar Cubedo-Ruiz, Maria Maldonado Vega, Jaime Garatuza Payan, Enrico Yépez González, Fannie Isela Parra Cota and Sergio de los Santos Villalobos

Soil Syst. 2024, 8(4), 112; https://doi.org/10.3390/soilsystems8040112 - 31 Oct 2024

Abstract

Agricultural practices affect the physical, chemical, and biological properties of soil in agroecosystems. This study evaluated the impact of food production strategies on the rhizosphere microbial communities in the Yaqui Valley, Mexico, on key crops (Medicago sativa, Brassica oleracea, Asparagus [...] Read more.

Agricultural practices affect the physical, chemical, and biological properties of soil in agroecosystems. This study evaluated the impact of food production strategies on the rhizosphere microbial communities in the Yaqui Valley, Mexico, on key crops (Medicago sativa, Brassica oleracea, Asparagus officinalis, Phaseolus vulgaris, Citrus sinensis, Zea mays, Solanum tuberosum, Triticum durum, and an undisturbed native ecosystem). Soil samples were collected from 30 cm depths across one-hectare fields and analyzed for bulk density, pH, organic matter content, and electrical conductivity. Standardized methods were used for these analyses, along with microbial isolation through culturing, PCR amplification, and DNA sequencing for microbial identification. The use of synthetic fertilizers in the region was linked to increased salinity and soil compaction. Organic matter content was notably low at ≤1.4%, which negatively impacted microbial diversity. A total of 317 microbial strains were isolated, with bacteria comprising 73% and fungi 27%. Bacillus was the most dominant bacterial genus (41% of isolates), while Aspergillus was the most abundant fungal genus (31% of isolates). Crop-specific microbial strains were identified. This study provides the first detailed insight into how agricultural practices shape microbial communities in the Yaqui Valley’s major crops, highlighting the link between soil properties and microbial diversity. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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17 pages, 7106 KiB

Open AccessArticle

Lowland Integrated Crop–Livestock Systems with Grass Crops Increases Pore Connectivity and Permeability, Without Requiring Soil Tillage

by Jordano Vaz Ambus, Amanda Romeiro Alves, Douglas Leandro Scheid, Antonio Celso Dantas Antonino and José Miguel Reichert

Soil Syst. 2024, 8(4), 111; https://doi.org/10.3390/soilsystems8040111 - 30 Oct 2024

Abstract

Enhancing integrated crop–livestock systems (ICLSs) to improve land-use efficiency is a critical goal. Understanding the ICLS impacts on lowland soils is key to sustainable agricultural practices. Our objective was to test whether adopting ICLSs in lowlands improves soil structure, pore connectivity, and water [...] Read more.

Enhancing integrated crop–livestock systems (ICLSs) to improve land-use efficiency is a critical goal. Understanding the ICLS impacts on lowland soils is key to sustainable agricultural practices. Our objective was to test whether adopting ICLSs in lowlands improves soil structure, pore connectivity, and water and air permeability. This study was conducted in a long-term field trial, consisting of the following production systems with flood-irrigation rice: rice–fallow–rice, under conventional tillage and absence of grazing (RFR-ct); rice-grazed ryegrass–rice, under no-tillage and grazing (RGrR-nt); rice-grazed ryegrass–soybean-grazed ryegrass–rice, under no-tillage and grazing (RGrS/RGrR-nt); and a grazed pasture-consortium (winter) and succession field (summer), with no-till rice every 4 years (P4R-nt). Core samples were collected after grazing (October 2018), harvesting (March 2019), and grazing (October 2019). We analyzed soil air permeability, saturated hydraulic conductivity, pore connectivity by computed tomography. Soil tillage in a semi-direct system generated discontinuous porosity. Systems with intense trampling or less surface protection are affected by shearing on topsoil, reducing pore continuity. ICLSs are mainly composed of ryegrass–rice mitigated the harmful effects of trampling, and improved soil structure and functioning. Systems without soil tillage exhibited higher pore connectivity and pores with vertical orientation. Finally, soil tillage is not required to improve structural quality in ICLSs. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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