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Soil Systems
Volume 7
Issue 3
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Soil Syst., Volume 7, Issue 3 (September 2023) – 17 articles

Cover Story (view full-size image): This review article aims to acknowledge the multifaceted functions of soil, and given its status as the largest terrestrial carbon store, to reaffirm its previously established importance in carbon sequestration. This article outlines the key variables that affect soil’s ability to trap carbon and highlights the significance of soil in halting climate change. A bibliometric study of seven sets of keywords relating to the significance of soil in carbon sequestration for climate change mitigation laid the foundation for this review. The literature review that followed, which was based on the bibliometric analysis, concentrated on carbon sequestration and the impact of the key factors that affect the amount of organic carbon in soil, including (1) climatic conditions; (2) topography; (3) parent material; (4) organisms; and (5) soil qualities. View this paper
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9 pages, 478 KiB  
Article
Saturated Hydraulic Conductivity of a Sandy Loam under No-Till and Intensive Tillage in a Corn–Soybean Rotation
by Jalal D. Jabro, William B. Stevens, William M. Iversen, Upendra M. Sainju and Brett L. Allen
Soil Syst. 2023, 7(3), 79; https://doi.org/10.3390/soilsystems7030079 - 13 Sep 2023
Cited by 1 | Viewed by 1817
Abstract
Tillage management practices have a dynamic impact on soil hydraulic properties and processes. There is a need for information about the effect of tillage practices on soil hydraulic properties for crops growing under sprinkler irrigation in the northern Great Plains. A long-term study [...] Read more.
Tillage management practices have a dynamic impact on soil hydraulic properties and processes. There is a need for information about the effect of tillage practices on soil hydraulic properties for crops growing under sprinkler irrigation in the northern Great Plains. A long-term study was conducted from 2014 to 2018 to examine the effect of no tillage (NT) and conventional tillage (CT) on the saturated hydraulic conductivity (Ks) of a sandy loam soil in a two-year corn (Zea mays L.)–soybean (Glycine max L.) rotation. In situ Ks measurements were taken in the center of crop rows within NT and CT plots using a pressure ring infiltrometer at the soil surface (0–15 cm) and a constant head well permeameter at the subsurface (15–30 cm). Results indicated that Ks values were well described by a log-normal distribution at both depths. Results showed that logarithmic Ks (log Ks) was not significantly impacted by tillage. Averaged over the five-year study, the log-transformed Ks of 100 measurements was not significantly affected by tillage in the surface layer under either corn or soybean nor in the subsurface layer under soybean. However, the mean soil log Ks in CT plots (1.784 mm h−1) was significantly greater than that in NT plots (1.186 mm h−1) in the 15–30 cm layer under corn, while Ks was nearly 50% greater in CT than in NT. Large values for the coefficient of variation (CV%) of Ks measurements exhibited significant spatial variations of Ks among plots within each tillage treatment at both the soil surface and subsurface layers under corn and soybean. Thus, more studies under different soils and cropping systems with a larger sample size per treatment are needed to lower spatial variability within treatments and validate the effect of tillage on soil hydraulic properties. Full article
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19 pages, 4060 KiB  
Review
Research Evolution on the Impact of Agronomic Practices on Soil Health from 1996 to 2021: A Bibliometric Analysis
by Mohamed Houssemeddine Sellami and Fabio Terribile
Soil Syst. 2023, 7(3), 78; https://doi.org/10.3390/soilsystems7030078 - 11 Sep 2023
Cited by 1 | Viewed by 2847
Abstract
In the last two decades, there has been a significant shift in focus towards soil health by international institutions, organizations, and scholars. Recognizing the vital role of soil in sustaining agriculture, ecosystems, and mitigating climate change, there has been a concerted effort to [...] Read more.
In the last two decades, there has been a significant shift in focus towards soil health by international institutions, organizations, and scholars. Recognizing the vital role of soil in sustaining agriculture, ecosystems, and mitigating climate change, there has been a concerted effort to study and understand soil health more comprehensively. In this study, a bibliometric analysis was performed in order to determine the research trend of the articles published in the Scopus database in the last 26 years on soil health experimental studies and agronomic practices conducted in field conditions on agricultural soils. It has been observed that, after 2013, there has been a significant increase in research articles on soil health, with the USA and India research institutions ranking as the most productive on this topic. There is an asymmetry in international cooperation among research institutions, as well as for scholars. In addition, the research topic is gradually shifting from the effects of soil management strategies, especially nutrient management, on soil organic carbon and yield to the study of the impact of soil management on biochemistry and microbiological soil activities and greenhouse gas emissions. Future research should focus into more integrated approaches to achieve soil indicators enabling to evaluate the impact of sustainable management practices (e.g., cropping practices) on soil health. Full article
(This article belongs to the Special Issue Advancements in Soil and Sustainable Agriculture)
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11 pages, 2433 KiB  
Article
Effect of Smoke Caused by Fires on the Enzymatic Activity of Forest Soils in the North Caucasus (Russian Federation)
by Mikhail Sergeevich Nizhelskiy, Kamil Shagidullovich Kazeev, Valeria Valerievna Vilkova, Anastasia Nikolaevna Fedorenko, Aslan Kaplanovich Shkhapatsev and Sergey Iliych Kolesnikov
Soil Syst. 2023, 7(3), 77; https://doi.org/10.3390/soilsystems7030077 - 29 Aug 2023
Cited by 4 | Viewed by 1676
Abstract
Forest fires can have a significant impact on soils, resulting in changes in biological indicators. Due to fire, high temperatures, and intensive generation of smoke from burning materials of different origin, the activity of soil enzymes is decreased. In this study are presented [...] Read more.
Forest fires can have a significant impact on soils, resulting in changes in biological indicators. Due to fire, high temperatures, and intensive generation of smoke from burning materials of different origin, the activity of soil enzymes is decreased. In this study are presented the results of modelling experiments on the impact of smoke on forest soils (Cambisols according to the World Reference Base for Soil Resources rating) of the Republic of Adygea, Nickel settlement (Russia). The findings demonstrated significant smoke exposure on the enzymatic activity of this type of soil. A decrease in the activity of such enzymes as catalase, peroxidase, polyphenol oxidase, and invertase within 60 min after soil treatment with smoke from burning materials of plant origin (pine sawdust) was established. A significant decrease in the activity of catalase relative to the control by 36%, phenoloxidases by 54–58%, and invertase from the hydrolase class by 31% was found. The integral index of soil enzymatic activity (IIEA) of the studied soils was also calculated. In addition, one of the informative diagnostic indicators is the pH of the soil suspension. The pH value for fumigated water was also determined to identify differences with the suspension. A reduction in the pH towards acidification was observed. The obtained findings may be used in a comprehensive assessment of pyrogenic effects on forest soils. Moreover, indicators are sensitive to this effect, which was confirmed by the results of the present research. Full article
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13 pages, 1016 KiB  
Article
Analysis of Molecular Structure Changes in Humic Acids from Manure-Amended Soils over 17 Years Using Elemental Analysis and Solid-State 13C Nuclear Magnetic Resonance Spectroscopy
by Ibrahim Mohammed, Busayo Kodaolu, Tiequan Zhang, Yutao Wang, Yuki Audette and James Longstaffe
Soil Syst. 2023, 7(3), 76; https://doi.org/10.3390/soilsystems7030076 - 21 Aug 2023
Cited by 2 | Viewed by 1797
Abstract
Soil organic matter (SOM) plays an important role in regulating plant nutrient availability. Here, the effects of the long-term application of different forms of processed swine manure on the SOM structure are explored through the analysis of humic acid (HA) using elemental analysis [...] Read more.
Soil organic matter (SOM) plays an important role in regulating plant nutrient availability. Here, the effects of the long-term application of different forms of processed swine manure on the SOM structure are explored through the analysis of humic acid (HA) using elemental analysis and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. The HAs from soils amended with liquid swine manure (LSM) and swine manure compost (SMC) are found to be more humified compared to the soils treated with solid swine manure (SSM) and the control (CK). The H/C and O/C molar ratios suggest that carboxyl-rich aliphatic structures are the most important class of biomolecules contributing to the LSM- and SMC-HA structures, while lignin-like structures are the most important biomolecules contributing to the CK- and SSM-HAs. SSM promoted the formation of aliphatic polar structures, which are more susceptible to aerobic biodegradation, whereas the CK facilitated the inclusion of condensed aromatic structures into the HA. Apart from the LSM-HA, the proportion of carboxylic acid functional groups reduced with manure application, while the proportion of phenolic acid functional groups increased. LSM-HA has the highest potential to enhance plant nutrient availability. Full article
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16 pages, 1621 KiB  
Review
Criteria for Assessing the Environmental Quality of Soils in a Mediterranean Region for Different Land Use
by Manuel Miguel Jordán Vidal
Soil Syst. 2023, 7(3), 75; https://doi.org/10.3390/soilsystems7030075 - 18 Aug 2023
Cited by 5 | Viewed by 2523
Abstract
Since the 1980s, there has been a notable increase in environmental sensitivity, which has decisively contributed to an improved perception of the role of soil in ecosystems. European (and especially Mediterranean) soils have a long tradition of use, which places them among the [...] Read more.
Since the 1980s, there has been a notable increase in environmental sensitivity, which has decisively contributed to an improved perception of the role of soil in ecosystems. European (and especially Mediterranean) soils have a long tradition of use, which places them among the three Earth soils that have been affected the most by anthropic pressure. The definition of soil quality identifies and recognizes the soil’s main functions regarding productivity, environmental quality, and human health. Interpreting the criteria for assessing soil quality requires continuous information on its state. Therefore, certain measurable characteristics and properties of the soil are useful, as they can be affected by processes that impact its quality, and analyzing its variation can reflect or show that impact. The parameters used to measure a soil’s state are called indicators. Indicators are useful because they provide summarized and simplified information on the state of a process, but with a meaning that goes beyond an association with an individual parameter. There is an urgent need for consensus among soil scientists and institutions on the concept of soil quality and the applicable environmental quality indicators, as well as establishing interpretative guides for the selected indicators. Soil quality can be analyzed and assessed using several scales with different analysis objectives, information requirements, soil data, implications, and consequences for appropriate soil management. Spanish soil scientists developed a methodological proposal to assess the environmental quality of soil, its environmental impact, and plan and organize land use in the scope of a Mediterranean region. This manuscript is a contribution to the knowledge of the state-of-the-art research in the field of assessing the environmental quality of soils, providing the vision of numerous authors and a methodological proposal for an assessment on a regional scale that may be of interest in other regions or fields of study. Full article
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20 pages, 1925 KiB  
Article
Unravelling the Combined Use of Soil and Microbial Technologies to Optimize Cultivation of Halophyte Limonium algarvense (Plumbaginaceae) Using Saline Soils and Water
by Amaia Nogales, Salvadora Navarro-Torre, Maria Manuela Abreu, Erika S. Santos, Ana Cortinhas, Rosalba Fors, Marion Bailly, Ana Sofia Róis and Ana Delaunay Caperta
Soil Syst. 2023, 7(3), 74; https://doi.org/10.3390/soilsystems7030074 - 17 Aug 2023
Cited by 1 | Viewed by 1903
Abstract
Salt-affected soils have detrimental effects on agriculture and ecosystems. However, these soils can still be used for halophyte (salt-tolerant plants) cultivation using brackish and/or saline water. In this study, we employed soil technologies and mutualistic microorganisms as a sustainable strategy to improve the [...] Read more.
Salt-affected soils have detrimental effects on agriculture and ecosystems. However, these soils can still be used for halophyte (salt-tolerant plants) cultivation using brackish and/or saline water. In this study, we employed soil technologies and mutualistic microorganisms as a sustainable strategy to improve the growth and reproduction of the halophyte Limonium algarvense Erben’s growth and reproduction under saline conditions. A microcosm assay was conducted under controlled greenhouse conditions to cultivate L. algarvense using a saline Fluvisol (FLU) amended—or not—with a Technosol (TEC). Plants were inoculated with the arbuscular mycorrhizal fungus (AMF) Rhizoglomus irregulare and/or a consortium of plant growth-promoting bacteria (PGPB), and they were irrigated with estuarine water. Soil enzyme analysis and physicochemical characterisation of the soils, collected at the beginning and at the end of the assay, were carried out. The physiological status of non-inoculated and inoculated plants was monitored during the assay for 4 months, and AMF root colonisation was evaluated. In FLU, only plants inoculated with the AMF survived. These plants had lower number of leaves, and shoot and root dry biomass than the ones grown in the TEC by the end of the assay. In the TEC, PGPB inoculation led to higher NDVI and PRI values, and AMF inoculation promoted higher reproductive development but not pollen fertility. The findings show that the combined use of soil and microbial technologies can be successfully applied to cultivate L. algarvense, suggesting their generalized use for other Limonium species with economic interest, while contributing to the sustainable use of marginal lands. Full article
(This article belongs to the Special Issue Crop Response to Soil and Water Salinity)
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16 pages, 1579 KiB  
Article
Exploring the Influence of Diverse Viticultural Systems on Soil Health Metrics in the Northern Black Sea Region
by Valeria Gabechaya, Irina Andreeva, Dmitriy Morev, Alexis Yaroslavtsev, Alexander Neaman and Ivan Vasenev
Soil Syst. 2023, 7(3), 73; https://doi.org/10.3390/soilsystems7030073 - 15 Aug 2023
Cited by 2 | Viewed by 1837
Abstract
The present study investigates the functionalecological status of typical light clay soils in vineyards in the southern region of Crimea, using both traditional (including fallow soils) and organic land-use systems. This analysis was carried out by examining agrochemical indicators, microbial respiratory activity, microbial [...] Read more.
The present study investigates the functionalecological status of typical light clay soils in vineyards in the southern region of Crimea, using both traditional (including fallow soils) and organic land-use systems. This analysis was carried out by examining agrochemical indicators, microbial respiratory activity, microbial biomass, and the ecological status of the microbial community. In organic vineyard soils, the mean substrate-induced respiration, microbial biomass carbon and the ratio of microbial biomass to organic carbon were found to be 2.8, 4.0, and 4.1 times higher, respectively, compared to conventional farm soils. On the contrary, the microbial metabolic coefficient was 1.4 times lower, signifying more favorable conditions for the functioning of the soil microbiota. The increased mobile sulfur content in organic vineyard soils (18.3 mg kg−1 vs. 8.0 mg kg−1 in traditional farms) and inadequate mobile phosphorus supply in some farms present potential risks. The suboptimal functional state of the microbiome in fallow soils previously under traditional plant protection necessitates comprehensive ecotoxicological analyses before development. Assessing the soil functional ecological status through an ecophysiological evaluation of the microbiome is vital for understanding ampelocenosis soils and making informed decisions on vineyard management practices. Full article
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16 pages, 1652 KiB  
Article
Soil Health Assessment to Evaluate Conservation Practices in SemiArid Cotton Systems at Producer Site Scale
by Veronica Acosta-Martinez, Jon Cotton, Lindsey C. Slaughter, Rajan Ghimire and Wayne Roper
Soil Syst. 2023, 7(3), 72; https://doi.org/10.3390/soilsystems7030072 - 9 Aug 2023
Cited by 5 | Viewed by 1927
Abstract
Maintaining soil health and sustainable crop production has been challenged by climate variability and wind erosion in semi-arid regions. To understand the initial effects of the transition of tilled cotton systems to no-tillage with winter wheat as a cover crop, we sampled 18 [...] Read more.
Maintaining soil health and sustainable crop production has been challenged by climate variability and wind erosion in semi-arid regions. To understand the initial effects of the transition of tilled cotton systems to no-tillage with winter wheat as a cover crop, we sampled 18 commercial grower sites from 2019 to 2022 in the Southern High Plains (SHP). We evaluated the soil biological component, which often responds rapidly to changes in residue additions or minimized soil disturbance providing an early indication of changes in soil health, especially in the low organic matter soils in this region. After two years, compared to tilled systems, no-till systems had significant increases in ester-linked fatty acid methyl ester (EL-FAME) bacterial and saprophytic and AMF fungal markers, enzyme activities of nutrient cycling, and various SOM pools, under both center-pivot irrigation and dryland. Similar increases were also observed in two dryland sites sampled before and up to two years after transition to no-till. Our study demonstrates the potential of no-tillage and cover crops to improve soil health in cotton production in semiarid regions, and a framework for a soil health assessment that links different soil health indicators with functions related to soil organic matter, soil water, and biogeochemical cycling. Full article
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14 pages, 614 KiB  
Article
Uptake of Fertilizer Nitrogen and Soil Nitrogen by Sorghum Sudangrass (Sorghum bicolor × Sorghum sudanense) in a Greenhouse Experiment with 15N-Labelled Ammonium Nitrate
by Lucas Knebl, Andreas Gattinger, Wiebke Niether and Christopher Brock
Soil Syst. 2023, 7(3), 71; https://doi.org/10.3390/soilsystems7030071 - 3 Aug 2023
Viewed by 1840
Abstract
A greenhouse experiment with sorghum sudangrass (Sorghum bicolor × Sorghum sudanense) and maize (Zea mays) was conducted to assess information on differences in their nitrogen and fertilizer utilization when used as energy crops. The aim was to contribute to [...] Read more.
A greenhouse experiment with sorghum sudangrass (Sorghum bicolor × Sorghum sudanense) and maize (Zea mays) was conducted to assess information on differences in their nitrogen and fertilizer utilization when used as energy crops. The aim was to contribute to the scarce data on sorghum sudangrass as an energy crop with regards to nitrogen derived from fertilizer (NdfF) in the plant’s biomass and fertilizer nitrogen utilization (FNU). Sorghum sudangrass and maize were each grown in eight bags of 45 L volume and harvested at maturity after 154 days. Each crop treatment was further divided in a control treatment (four bags each) that did not receive N fertilization and a fertilization treatment (four bags each) that received 1.76 g N, applying a 15N-labelled liquid ammonium nitrate fertilizer. Fertilization took place at the start of the experiment. After harvest, the whole plant was divided in the fractions “aboveground biomass” (ABM) and “stubble + rootstock” (S + R). Weight, N content and 15N content were recorded for each fraction. In addition, N content and 15N content were assessed in the soil before sowing and after harvest. The experiment showed that FNU of sorghum sudangrass (65%) was significantly higher than that of maize (49%). Both crops accumulated more soil N than fertilizer N. The share of fertilizer N on total N uptake was also higher with sorghum sudangrass (NdfF = 38%) compared to maize (NdfF = 34%). The observations made with our control plant (maize), showed that the results are plausible and comparable to other 15N studies on maize regarding yields, NdfF, and FNU, leading to the assumption that results on sorghum sudangrass are plausible as well. We therefore conclude that the results of our study can be used for the preliminary parametrization of sorghum sudangrass in soil organic matter (SOM) balance at field level. 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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16 pages, 4342 KiB  
Article
Comparison of the Structure of Soil Microbial Communities of Different Ecosystems Using the Microbiome Sequencing Approach
by Audrius Kačergius, Diana Sivojienė, Renata Gudiukaitė, Eugenija Bakšienė, Aistė Masevičienė and Lina Žičkienė
Soil Syst. 2023, 7(3), 70; https://doi.org/10.3390/soilsystems7030070 - 2 Aug 2023
Cited by 1 | Viewed by 2694
Abstract
In this study, we aimed to compare the functional and taxonomic composition of soil microbial communities in different ecosystems, agricultural, natural grasslands, and old-growth forests, in the context of different environmental conditions. In this research, cultivable microbial quantification was performed by conventional plate-count [...] Read more.
In this study, we aimed to compare the functional and taxonomic composition of soil microbial communities in different ecosystems, agricultural, natural grasslands, and old-growth forests, in the context of different environmental conditions. In this research, cultivable microbial quantification was performed by conventional plate-count techniques using different selective media. The taxonomic structure of microbe communities was evaluated using NGS metagenomic sequencing on the Illumina platform NovaSeq. The taxonomic analysis showed that individual land uses are characterized by the specific structure of communities; some taxonomic groups are specific only to agricultural, grassland, or forest ecosystems. After determining the abundance of functional groups of culturable microorganisms by the conventional plate-count method, statistically significant quantitative differences in physiological groups between the individual ecosystems were revealed. The metagenomic analysis revealed that different ecosystems are characterized by specific taxonomic groups of microorganisms and that general alpha diversity varies among individual land-use samples. Since the most unstable soil systems are agricultural, they are likely to suffer the most and will suffer more in the future from climate change than natural ones. Full article
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17 pages, 1744 KiB  
Article
Phytomanagement of Zn- and Cd-Contaminated Soil: Helianthus annuus Biomass Production and Metal Remediation Abilities with Plant-Growth-Promoting Microbiota Assistance
by Ana M. S. Paulo, Nidia S. Caetano, Paula M. L. Castro and Ana P. G. C. Marques
Soil Syst. 2023, 7(3), 69; https://doi.org/10.3390/soilsystems7030069 - 31 Jul 2023
Cited by 2 | Viewed by 1863
Abstract
Mining and industrial activity are contributing to the increase in heavy metal (HM) pollution in soils. Phytoremediation coupled to selected rhizosphere microbiota is an environmentally friendly technology designed to promote HM bioremediation in soils. In this study, sunflower (Helianthus annuus L.) was [...] Read more.
Mining and industrial activity are contributing to the increase in heavy metal (HM) pollution in soils. Phytoremediation coupled to selected rhizosphere microbiota is an environmentally friendly technology designed to promote HM bioremediation in soils. In this study, sunflower (Helianthus annuus L.) was used together with Rhizophagus irregularis, an arbuscular mycorrhizal fungi (AMF), and Cupriavidus sp. strain 1C2, a plant growth promoting rhizobacteria (PGPR), as a phytoremediation strategy to remove Zn and Cd from an industrial soil (599 mg Zn kg−1 and 1.2 mg Cd kg−1). The work aimed to understand if it is possible to gradually remediate the tested soil while simultaneously obtaining significant yields of biomass with further energetic values by comparison to the conventional growth of the plant in agricultural (non-contaminated) soil. The H. annuus biomass harvested in the contaminated industrial soil was 17% lower than that grown in the agricultural soil—corresponding to yields of 19, 620, 199 and 52 g m−2 of roots, stems, flowers and seeds. It was possible to remove ca. 0.04 and 0.91% of the Zn and Cd of the industrial soil, respectively, via the HM accumulation on the biomass produced. The survival of applied microbiota was indicated by a high root colonization rate of AMF (about 50% more than in non-inoculated agricultural soil) and identification of strain 1C2 in the rhizosphere at the end of the phytoremediation assay. In this study, a phytoremediation strategy encompassing the application of an energetic crop inoculated with known beneficial microbiota applied to a real contaminated soil was successfully tested, with the production of plant biomass with the potential for upstream energetic valorisation purposes. Full article
(This article belongs to the Special Issue Soil Bioremediation)
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15 pages, 1992 KiB  
Article
Phytotoxic Effects of Al on Root Growth Are Confounded in the Presence of Fulvic and Humic Acids
by Stephen Harper and Neal Menzies
Soil Syst. 2023, 7(3), 68; https://doi.org/10.3390/soilsystems7030068 - 27 Jul 2023
Cited by 1 | Viewed by 1585
Abstract
Background and Aims: In acidic soils, aluminum (Al) toxicity remains a critical crop limitation that can be ameliorated by organic amendments through Al complexation with high-molecular-weight carbon compounds, particularly fulvic and humic acids (FA and HA) However, no research discriminates between the direct [...] Read more.
Background and Aims: In acidic soils, aluminum (Al) toxicity remains a critical crop limitation that can be ameliorated by organic amendments through Al complexation with high-molecular-weight carbon compounds, particularly fulvic and humic acids (FA and HA) However, no research discriminates between the direct effects of FA and HA on plant growth and the indirect effect that occurs through ameliorating Al toxicity. This study delineates the direct and indirect effects of FA and HA on plant growth. Methods: Eucalyptus and Hay FA and HA, and Al effects on maize (Zea mays) root growth were investigated using dilute nutrient solution. Five Al concentrations (0–270 µM) were combined with four organic acid (OA) treatments, including Nil-OA, FA40, and HA40 (each at 40 mg C L−1) and a combined treatment FA40HA40 (80 mg C L−1). Results: Eucalyptus FA and HA stimulated root growth by ~20% compared with root growth in the Nil-OA (17.4 cm). In the absence of Al, Hay FA and HA inhibited root growth (by ~20%) compared with the Nil-OA but the addition of Al resulted in stimulation of root growth. In the presence of FA and HA, root growth was not inhibited by nominally toxic monomeric Al (Al3+) concentrations (~20 µM Al). However, when expressed on a relative basis to remove the direct effect of the ligand, the response was consistent with Al toxicity. Conclusions: The effects of FA and HA were either inhibitory or stimulatory depending on the source while both sources of FA and HA mitigated Al toxicity through complexation. The study provides mechanistic data that highlights limitations of soil bioassays where the direct effects of organic ligands on root growth are confounded with the indirect effect of their reduction of Al toxicity. These two independent processes must be considered in evaluating the amelioration of Al by organic amendments. Full article
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19 pages, 1994 KiB  
Article
Exogenous Selenium Improves Physio-Biochemical and Performance of Drought-Stressed Phaseolus vulgaris Seeded in Saline Soil
by Wael M. Semida, Taia A. Abd El-Mageed, Mohammed A. H. Gyushi, Shimaa A. Abd El-Mageed, Mostafa M. Rady, Abdelsattar Abdelkhalik, Othmane Merah, Ayman El Sabagh, Ibrahim M. El-Metwally, Mervat Sh. Sadak and Magdi T. Abdelhamid
Soil Syst. 2023, 7(3), 67; https://doi.org/10.3390/soilsystems7030067 - 20 Jul 2023
Cited by 10 | Viewed by 1874
Abstract
Water and salt stresses are among the most important global problems that limit the growth and production of several crops. The current study aims at the possibility of mitigating the effect of deficit irrigation of common bean plants growing in saline lands by [...] Read more.
Water and salt stresses are among the most important global problems that limit the growth and production of several crops. The current study aims at the possibility of mitigating the effect of deficit irrigation of common bean plants growing in saline lands by foliar spraying with selenium via the assessment of growth, productivity, physiological, and biochemical measurements. In our study, two field-based trials were conducted in 2017 and 2018 to examine the influence of three selenium (Se) concentrations (0 (Se0), 25 (Se25), and 50 mg L−1 (Se50)) on common bean plants grown under full irrigation (I100 = 100% of the crop evapotranspiration; ETc) and deficit irrigation (I80 = 80% of ETc, and I60 = 60% of ETc). Bean plants exposed to water stress led to a notable reduction in growth, yield, water productivity (WP), water status, SPAD value, and chlorophyll a fluorescence features (Fv/Fm and PI). However, foliar spraying of selenium at 25 or 50 mg L−1 on stressed bean plants attenuated the harmful effects of water stress. The findings suggest that foliage application of 25 or 50 mg L−1 selenium to common bean plants grown under I80 resulted in a higher membrane stability index, relative water content, SPAD chlorophyll index, and better efficiency of photosystem II (Fv/Fm, and PI). Water deficit at 20% increased the WP by 17%; however, supplementation of 25 or 50 mg L−1 selenium mediated further increases in WP up to 26%. Exogenous application of selenium (25 mg L−1 or 50 mg L−1) to water-stressed bean plants elevated the plant defense system component, given that it increased the free proline, ascorbic acid, and glutathione levels, as well as antioxidant enzymes (SOD, APX, GPX, and CAT). It was concluded that the application of higher levels (25 or/and 50 mg L−1) of Se improves plant water status as well as the growth and yield of common beans cultivated in saline soil. Full article
(This article belongs to the Special Issue Crop Response to Soil and Water Salinity)
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18 pages, 1155 KiB  
Article
Glyphosate-Based Herbicide Formulations with Greater Impact on Earthworms and Water Infiltration than Pure Glyphosate
by Verena Brandmaier, Anna Altmanninger, Friedrich Leisch, Edith Gruber, Eszter Takács, Mária Mörtl, Szandra Klátyik, András Székács and Johann G. Zaller
Soil Syst. 2023, 7(3), 66; https://doi.org/10.3390/soilsystems7030066 - 20 Jul 2023
Cited by 5 | Viewed by 1905
Abstract
Glyphosate is the most widely used active ingredient (AI) in thousands of glyphosate-based herbicides (GBHs) worldwide. Short-term impacts of AIs or GBHs on earthworms are well known, but few studies have examined long-term legacy effects >3 months after application. In a pot experiment, [...] Read more.
Glyphosate is the most widely used active ingredient (AI) in thousands of glyphosate-based herbicides (GBHs) worldwide. Short-term impacts of AIs or GBHs on earthworms are well known, but few studies have examined long-term legacy effects >3 months after application. In a pot experiment, we studied both short-term and long-term effects on deep burrowing earthworms (Lumbricus terrestris) and soil functions. Therefore, the cover crop Sinapis alba was grown in soils with either 3.0% or 4.1% soil organic matter content (SOM) and either sprayed with a GBH (Touchdown Quattro, Roundup PowerFlex, or Roundup LB Plus) or the respective glyphosate AI (diammonium-, potassium-, or isopropylamine-salt) or hand weeded (control). Long-term effects showed increased earthworm activity under GBHs even 4 months after application, but similar activity under AIs and control. Another application of the same treatments 5 months after the previous one also increased earthworm activity under GBHs, especially at high SOM levels. Water infiltration after a simulated heavy rainfall was 50% lower, and leaching was 30% higher under GBH than under AI application or hand weeding. Individual GBHs and AIs varied in their effects and were influenced by SOM and soil moisture. Full disclosure of all ingredients in GBH formulations would be necessary to allow a comprehensive assessment of environmental risks. Full article
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15 pages, 1804 KiB  
Article
Revealing the Combined Effects of Microplastics, Zn, and Cd on Soil Properties and Metal Accumulation by Leafy Vegetables: A Preliminary Investigation by a Laboratory Experiment
by John Bethanis and Evangelia E. Golia
Soil Syst. 2023, 7(3), 65; https://doi.org/10.3390/soilsystems7030065 - 17 Jul 2023
Cited by 15 | Viewed by 2908
Abstract
A pot experiment was carried out to investigate the effects of polyethylene (PE), a broadly utilized polymer type, on soil properties and lettuce growth. Two Zn- and Cd-contaminated soil samples were obtained from urban and rural areas of Greece, respectively. PE fragments (<5 [...] Read more.
A pot experiment was carried out to investigate the effects of polyethylene (PE), a broadly utilized polymer type, on soil properties and lettuce growth. Two Zn- and Cd-contaminated soil samples were obtained from urban and rural areas of Greece, respectively. PE fragments (<5 mm) were added at different concentrations (2.5%, 5% w/w). Lettuce seeds were then planted in the pots in a completely randomized experiment. Plant growth patterns and tissue metal accumulation were investigated. The presence of PE in soils resulted in a reduction in pH, significantly enhanced the organic matter content, and increased the cation-exchange capacity. The availability of both metals was also increased. Metal migration from soil to plant was determined using appropriate tools and indexes. A higher metal concentration was detected in lettuce roots compared with that in the edible leaves. The presence of PE MPs (2.5% w/w) increased the amount of available Zn more than that of Cd in highly contaminated soils. When PE MPs were added to agricultural soil, Zn concentrations increased in the plant leaves by 9.1% (2.5% w/w) and 21.1% (5% w/w). Considering that both metals and microplastics cannot be easily and quickly degraded, the fact that the less toxic metal is more available to plants is encouraging. Taking into account the physicochemical soil features, decision makers may be able to limit the risks to human health from the coexistence of heavy metals and microplastics in soils. Full article
(This article belongs to the Special Issue Research on Soil Management and Conservation)
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21 pages, 991 KiB  
Review
Soil Carbon Sequestration in the Context of Climate Change Mitigation: A Review
by Cristina I. Dias Rodrigues, Luís Miguel Brito and Leonel J. R. Nunes
Soil Syst. 2023, 7(3), 64; https://doi.org/10.3390/soilsystems7030064 - 3 Jul 2023
Cited by 41 | Viewed by 16053
Abstract
This review article aims to acknowledge the multifaceted functions of soil, and given its status as the largest terrestrial carbon store, to reaffirm its previously established importance in carbon sequestration. The article outlines the key variables that affect soil’s ability to trap carbon [...] Read more.
This review article aims to acknowledge the multifaceted functions of soil, and given its status as the largest terrestrial carbon store, to reaffirm its previously established importance in carbon sequestration. The article outlines the key variables that affect soil’s ability to trap carbon and highlights the significance of soil in halting climate change. A bibliometric study of seven sets of keywords relating to the significance of soil in carbon sequestration for climate change mitigation laid the foundation for this review. The literature review that followed, which was based on the bibliometric analysis, concentrated on carbon sequestration and the impact of the key factors that affect the amount of organic carbon in soil, including (1) climatic conditions; (2) topography; (3) parent material; (4) organisms; and (5) soil qualities. The goal of this review article is to recognize the diverse roles of soil, while reasserting its well-documented significance in carbon sequestration. This is particularly important considering soil’s position as the largest terrestrial storehouse of carbon. Full article
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15 pages, 2692 KiB  
Article
The Impact of Flood Frequency on the Heterogeneity of Floodplain Surface Soil Properties
by Scott Rayburg, Melissa Neave and Justin Thompson-Laing
Soil Syst. 2023, 7(3), 63; https://doi.org/10.3390/soilsystems7030063 - 22 Jun 2023
Cited by 3 | Viewed by 1898
Abstract
Floodplain soils are subject to quasi-periodic flood disturbances. This flooding serves to enrich floodplain soils, increasing their fertility and often making them ideal locations for agriculture. However, what is less well understood is how the frequency of flooding impacts on soil fertility and [...] Read more.
Floodplain soils are subject to quasi-periodic flood disturbances. This flooding serves to enrich floodplain soils, increasing their fertility and often making them ideal locations for agriculture. However, what is less well understood is how the frequency of flooding impacts on soil fertility and the diversity of soil character. This study investigates how flood frequency influences the heterogeneity (assessed using 26 physical and geochemical soil properties) of floodplain soils in a semi-arid floodplain wetland system in New South Wales, Australia. The study includes an investigation of soil properties across four flood frequency (or disturbance frequency) categories ranging from frequent through to infrequent flood disturbance. Thirty samples were collected from each zone and the physical and geochemical soil data were analyzed using a suite of univariate and multivariate statistical tests. The results show that sites subject to an intermediate level of flood disturbance have a greater level of diversity in soil properties than those sites subject to frequent flood disturbances. These results reflect those of the Intermediate Disturbance Hypothesis, an ecological theory that posits the highest biological diversity will also be found in intermediately disturbed environments and suggests that there might be physical habitat drivers of biological diversity in intermediately disturbed floodplains. Full article
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