Pub Date : 2023-04-05DOI: 10.3390/soilsystems7020031
This research analyzes the relationships between “soil” and “organisms” within the framework of the Jenny equation, a fundamental expression in soil science that is the theoretical basis for modeling the complex occurrence of soils on landscapes. This analysis is based on the interpretation of the indeterminate function “f” of the equation as “statistical dependence between categorical variables”. The categories of the “soil” component of the equation have been defined as “diagnostic horizons”, and those of the “organisms” factor as synthetic types of “land cover”. After applying these criteria to 424 soil profiles studied in a region with an oceanic climate in northern Spain, a multiple correspondence analysis showed pedologically consistent groupings between diagnostic horizons and categories of climate, land cover, relief, and parent material factors. Subsequently, a bivariate analysis detailed pedologically consistent relationships between diagnostic horizons and land cover categories. In the context the scarcity of quantitative information on soil and forming factor relationships, this work provides criteria to statistically assess the role of land cover in such relationships. This soil forming factor is the one whose spatial representation is more generalized and detailed, hence its interest in the development of soil mapping models.
{"title":"Soil and Land Cover Interrelationships: An Analysis Based on the Jenny’s Equation","authors":"","doi":"10.3390/soilsystems7020031","DOIUrl":"https://doi.org/10.3390/soilsystems7020031","url":null,"abstract":"This research analyzes the relationships between “soil” and “organisms” within the framework of the Jenny equation, a fundamental expression in soil science that is the theoretical basis for modeling the complex occurrence of soils on landscapes. This analysis is based on the interpretation of the indeterminate function “f” of the equation as “statistical dependence between categorical variables”. The categories of the “soil” component of the equation have been defined as “diagnostic horizons”, and those of the “organisms” factor as synthetic types of “land cover”. After applying these criteria to 424 soil profiles studied in a region with an oceanic climate in northern Spain, a multiple correspondence analysis showed pedologically consistent groupings between diagnostic horizons and categories of climate, land cover, relief, and parent material factors. Subsequently, a bivariate analysis detailed pedologically consistent relationships between diagnostic horizons and land cover categories. In the context the scarcity of quantitative information on soil and forming factor relationships, this work provides criteria to statistically assess the role of land cover in such relationships. This soil forming factor is the one whose spatial representation is more generalized and detailed, hence its interest in the development of soil mapping models.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45846402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.3390/soilsystems7020030
F. C. Pereira, Mitchell Donovan, Carol M. S. Smith, S. Charters, T. Maxwell, P. Gregorini
Grazing management to reduce soil erosion is paramount for preserving and enhancing grassland health under pastoral livestock production systems. However, as the focus of these production systems is to increase productivity, the inclusion of the soil and its complexity in grazing management has been usually neglected. Detailed consideration of the soil spatio-temporal susceptibility to erosion may be best approached with simulation modelling. To understand and explore the spatio-temporal impact of grazing strategies on soil surface erosion, this work used a geospatial model approach in a high-country pastoral livestock production system in New Zealand as a case study. We modelled 45 scenarios characterized by different stock densities and occupation periods applied for each season of the year and for different livestock types: sheep, beef, and deer, producing a total of 540 scenarios. In addition, we included scenarios to represent ungrazed pastures for each season and the current grazing management of the case study station as the baseline for comparisons (resulting in a total of 545 scenarios). Spatio-temporal variation of natural soil superficial erosion from ungrazed pastures appears to be more relevant than the impact of manipulating grazing intensity and indicates that paddocks in our study area have different capacities to support grazing which also changes during seasons. Increases in occupation period seem more detrimental to soil erosion compared to increases in stock density, and cattle are the most detrimental stock type compared to sheep and deer. Our results suggest that grassland health can be enhanced in LUMGS by applying context-adjusted grazing management strategies according to the station spatio-temporal heterogeneity and susceptibility to erosion.
{"title":"A Geospatial Modelling Approach to Understand the Spatio-Temporal Impacts of Grazing on Soil Susceptibility to Erosion","authors":"F. C. Pereira, Mitchell Donovan, Carol M. S. Smith, S. Charters, T. Maxwell, P. Gregorini","doi":"10.3390/soilsystems7020030","DOIUrl":"https://doi.org/10.3390/soilsystems7020030","url":null,"abstract":"Grazing management to reduce soil erosion is paramount for preserving and enhancing grassland health under pastoral livestock production systems. However, as the focus of these production systems is to increase productivity, the inclusion of the soil and its complexity in grazing management has been usually neglected. Detailed consideration of the soil spatio-temporal susceptibility to erosion may be best approached with simulation modelling. To understand and explore the spatio-temporal impact of grazing strategies on soil surface erosion, this work used a geospatial model approach in a high-country pastoral livestock production system in New Zealand as a case study. We modelled 45 scenarios characterized by different stock densities and occupation periods applied for each season of the year and for different livestock types: sheep, beef, and deer, producing a total of 540 scenarios. In addition, we included scenarios to represent ungrazed pastures for each season and the current grazing management of the case study station as the baseline for comparisons (resulting in a total of 545 scenarios). Spatio-temporal variation of natural soil superficial erosion from ungrazed pastures appears to be more relevant than the impact of manipulating grazing intensity and indicates that paddocks in our study area have different capacities to support grazing which also changes during seasons. Increases in occupation period seem more detrimental to soil erosion compared to increases in stock density, and cattle are the most detrimental stock type compared to sheep and deer. Our results suggest that grassland health can be enhanced in LUMGS by applying context-adjusted grazing management strategies according to the station spatio-temporal heterogeneity and susceptibility to erosion.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43329856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-22DOI: 10.3390/soilsystems7010029
T. Williams
Baculoviruses are DNA viruses that can naturally control insects and form the basis for a range of biological insecticides. These viruses are occluded in a crystalline protein matrix, the occlusion body (OB), which favors their persistence in the environment until consumed by a susceptible insect. This review presents evidence that baculoviruses are perfectly adapted to persist in soil. In support of this assertion, detailed evidence is presented concerning the stability of virus OBs in soil, the mechanisms and processes that affect OB transport to soil, OB persistence and movement through the soil layers, and the transport of the virus back to the host’s foodplant for subsequent transmission. The soil reservoir interacts with the host insect, the foodplant and the biotic and abiotic factors in the environment, all of which influence the function of the soil OB reservoir. Agricultural practices that conserve the soil reservoir can result in improved pest control. The soil is also an overlooked source of genetic diversity for the design of baculovirus-based insecticides. Finally, the principal issues that remain to be elucidated are highlighted, particularly with reference to those that affect the soil–baculovirus relationship and the impact of the soil OB reservoir on insect populations.
{"title":"Soil as an Environmental Reservoir for Baculoviruses: Persistence, Dispersal and Role in Pest Control","authors":"T. Williams","doi":"10.3390/soilsystems7010029","DOIUrl":"https://doi.org/10.3390/soilsystems7010029","url":null,"abstract":"Baculoviruses are DNA viruses that can naturally control insects and form the basis for a range of biological insecticides. These viruses are occluded in a crystalline protein matrix, the occlusion body (OB), which favors their persistence in the environment until consumed by a susceptible insect. This review presents evidence that baculoviruses are perfectly adapted to persist in soil. In support of this assertion, detailed evidence is presented concerning the stability of virus OBs in soil, the mechanisms and processes that affect OB transport to soil, OB persistence and movement through the soil layers, and the transport of the virus back to the host’s foodplant for subsequent transmission. The soil reservoir interacts with the host insect, the foodplant and the biotic and abiotic factors in the environment, all of which influence the function of the soil OB reservoir. Agricultural practices that conserve the soil reservoir can result in improved pest control. The soil is also an overlooked source of genetic diversity for the design of baculovirus-based insecticides. Finally, the principal issues that remain to be elucidated are highlighted, particularly with reference to those that affect the soil–baculovirus relationship and the impact of the soil OB reservoir on insect populations.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43289068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-20DOI: 10.3390/soilsystems7010028
S. Papadimou, O. Kantzou, M. Chartodiplomenou, E. Golia
When residents of Volos, a city in central Greece, are trying to recall their daily life after the end of the quarantine due to COVID-19, the soil pollution survey provided valuable insights, which are compared with a 4-year study carried out in that area before the pandemic period. Using appropriate indices, namely contamination factor (CF), pollution load index (PLI), geo-accumulation index (Igeo), ecological risk factor (Er), and potential ecological risk index (RI), and using geostatistical tools, maps were constructed for each metal (Cu, Zn, Pb, Ni, Cd, Co, Cr, Mn). Variations in the values of the contamination indices showed a significant redistribution in pollutant load from areas previously polluted by high vehicle traffic and the activities of the main port to the residential areas, where the habitants have their homes and playgrounds. The study showed that Cu, Zn, Pb, and Co concentrations increased during the pandemic period by 10%, 22.7%, 3.7%, and 23.1%, respectively. Ni’s concentration remained almost constant, while Cd, Cr, and Mn concentrations were decreased by 21.6%, 22.2%, and 9.5%, respectively. Fluctuations in the concentrations and corresponding contamination and ecological indices of the elements can serve as a means for highlighting potential sources of pollution. Therefore, although the pandemic period created anxiety, stress, and economic hardship for citizens, it may prove to be a valuable tool for investigating the sources of pollution in urban soils. The study of these results could potentially lead to optimal ways for managing the environmental crisis and solve persistent problems that pose risks to both the soil environment and human health.
{"title":"Urban Soil Pollution by Heavy Metals: Effect of the Lockdown during the Period of COVID-19 on Pollutant Levels over a Five-Year Study","authors":"S. Papadimou, O. Kantzou, M. Chartodiplomenou, E. Golia","doi":"10.3390/soilsystems7010028","DOIUrl":"https://doi.org/10.3390/soilsystems7010028","url":null,"abstract":"When residents of Volos, a city in central Greece, are trying to recall their daily life after the end of the quarantine due to COVID-19, the soil pollution survey provided valuable insights, which are compared with a 4-year study carried out in that area before the pandemic period. Using appropriate indices, namely contamination factor (CF), pollution load index (PLI), geo-accumulation index (Igeo), ecological risk factor (Er), and potential ecological risk index (RI), and using geostatistical tools, maps were constructed for each metal (Cu, Zn, Pb, Ni, Cd, Co, Cr, Mn). Variations in the values of the contamination indices showed a significant redistribution in pollutant load from areas previously polluted by high vehicle traffic and the activities of the main port to the residential areas, where the habitants have their homes and playgrounds. The study showed that Cu, Zn, Pb, and Co concentrations increased during the pandemic period by 10%, 22.7%, 3.7%, and 23.1%, respectively. Ni’s concentration remained almost constant, while Cd, Cr, and Mn concentrations were decreased by 21.6%, 22.2%, and 9.5%, respectively. Fluctuations in the concentrations and corresponding contamination and ecological indices of the elements can serve as a means for highlighting potential sources of pollution. Therefore, although the pandemic period created anxiety, stress, and economic hardship for citizens, it may prove to be a valuable tool for investigating the sources of pollution in urban soils. The study of these results could potentially lead to optimal ways for managing the environmental crisis and solve persistent problems that pose risks to both the soil environment and human health.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47322588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-17DOI: 10.3390/soilsystems7010027
C. Bettigole, Juliana Hanle, Daniel A. Kane, Zoe Pagliaro, Shaylan Kolodney, Sylvana Szuhay, Miles Chandler, Eli Hersh, S. Wood, B. Basso, Douglas Jeffrey Goodwin, Shane Hardy, Zachary Wolf, K. Covey
Soils comprise the largest pool of terrestrial carbon yet have lost significant stocks due to human activity. Changes to land management in cropland and grazing systems present opportunities to sequester carbon in soils at large scales. Uncertainty in the magnitude of this potential impact is largely driven by the difficulties and costs associated with measuring near-surface (0–30 cm) soil carbon concentrations; a key component of soil carbon stock assessments. Many techniques exist to optimize sampling, yet few studies have compared these techniques at varying sample intensities. In this study, we performed ex-ante, high-intensity sampling for soil carbon concentrations at four farms in the eastern United States. We used post hoc Monte-Carlo bootstrapping to investigate the most efficient sampling approaches for soil carbon inventory: K-means stratification, Conditioned Latin Hypercube Sampling (cLHS), simple random, and regular grid. No two study sites displayed similar patterns across all sampling techniques, although cLHS and grid emerged as the most efficient sampling schemes across all sites and strata sizes. The number of strata chosen when using K-means stratification can have a significant impact on sample efficiency, and we caution future inventories from using small strata n, while avoiding even allocation of sample between strata. Our findings reinforce the need for adaptive sampling methodologies where initial site inventory can inform primary, robust inventory with site-specific sampling techniques.
{"title":"Optimizing Sampling Strategies for Near-Surface Soil Carbon Inventory: One Size Doesn’t Fit All","authors":"C. Bettigole, Juliana Hanle, Daniel A. Kane, Zoe Pagliaro, Shaylan Kolodney, Sylvana Szuhay, Miles Chandler, Eli Hersh, S. Wood, B. Basso, Douglas Jeffrey Goodwin, Shane Hardy, Zachary Wolf, K. Covey","doi":"10.3390/soilsystems7010027","DOIUrl":"https://doi.org/10.3390/soilsystems7010027","url":null,"abstract":"Soils comprise the largest pool of terrestrial carbon yet have lost significant stocks due to human activity. Changes to land management in cropland and grazing systems present opportunities to sequester carbon in soils at large scales. Uncertainty in the magnitude of this potential impact is largely driven by the difficulties and costs associated with measuring near-surface (0–30 cm) soil carbon concentrations; a key component of soil carbon stock assessments. Many techniques exist to optimize sampling, yet few studies have compared these techniques at varying sample intensities. In this study, we performed ex-ante, high-intensity sampling for soil carbon concentrations at four farms in the eastern United States. We used post hoc Monte-Carlo bootstrapping to investigate the most efficient sampling approaches for soil carbon inventory: K-means stratification, Conditioned Latin Hypercube Sampling (cLHS), simple random, and regular grid. No two study sites displayed similar patterns across all sampling techniques, although cLHS and grid emerged as the most efficient sampling schemes across all sites and strata sizes. The number of strata chosen when using K-means stratification can have a significant impact on sample efficiency, and we caution future inventories from using small strata n, while avoiding even allocation of sample between strata. Our findings reinforce the need for adaptive sampling methodologies where initial site inventory can inform primary, robust inventory with site-specific sampling techniques.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47160335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-12DOI: 10.3390/soilsystems7010026
M. Al-Toobi, R. Janke, M. Khan, Mushtaque Ahmed, Waleed M. Al-Busaidi, A. Rehman
Rapidly increasing salinization of arable land is a major threat to crop production globally, and the soil of regions with arid environments, such as Oman, are more prone to this menace. In this work, two complementary studies were carried out to evaluate the effect of soil amendments on soil physicochemical properties and growth of cucumber seedlings. In the first study, high- and low-saline soils were used with or without perlite. The amendments tested included mango wood biochar, silica, and biochar + silica, while no amendment was taken as the control. The second study included two cucumber cultivars and irrigation water with two salinity treatments, along with the same four soil amendments. The results showed that soil amendment with biochar alone or with silica enhanced the soil organic matter and NO3, P, and K concentration, while silica amendment substantially enhanced the soil Si level in both studies. Saline soil and irrigation water inhibited seedling emergence and plant growth in both experiments. However, the addition of biochar and silica alone or in combination increased the cucumber seedling dry weight from 39.5 to 77.3% under salt stress compared to the control. Likewise, silica and biochar + silica reduced the sap Na accumulation by 29–31.1% under high salinity. Application of biochar under high salinity resulted in 87.2% increase in sap K. Soil amendments with biochar and silica or their combination have the potential to reduce the adverse effect of salt stress on cucumber.
{"title":"Silica and Biochar Amendments Improve Cucumber Growth under Saline Conditions","authors":"M. Al-Toobi, R. Janke, M. Khan, Mushtaque Ahmed, Waleed M. Al-Busaidi, A. Rehman","doi":"10.3390/soilsystems7010026","DOIUrl":"https://doi.org/10.3390/soilsystems7010026","url":null,"abstract":"Rapidly increasing salinization of arable land is a major threat to crop production globally, and the soil of regions with arid environments, such as Oman, are more prone to this menace. In this work, two complementary studies were carried out to evaluate the effect of soil amendments on soil physicochemical properties and growth of cucumber seedlings. In the first study, high- and low-saline soils were used with or without perlite. The amendments tested included mango wood biochar, silica, and biochar + silica, while no amendment was taken as the control. The second study included two cucumber cultivars and irrigation water with two salinity treatments, along with the same four soil amendments. The results showed that soil amendment with biochar alone or with silica enhanced the soil organic matter and NO3, P, and K concentration, while silica amendment substantially enhanced the soil Si level in both studies. Saline soil and irrigation water inhibited seedling emergence and plant growth in both experiments. However, the addition of biochar and silica alone or in combination increased the cucumber seedling dry weight from 39.5 to 77.3% under salt stress compared to the control. Likewise, silica and biochar + silica reduced the sap Na accumulation by 29–31.1% under high salinity. Application of biochar under high salinity resulted in 87.2% increase in sap K. Soil amendments with biochar and silica or their combination have the potential to reduce the adverse effect of salt stress on cucumber.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45295005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-10DOI: 10.3390/soilsystems7010025
N. Phillips, I. Moffat, A. Mackay, B. G. Jones
Despite the wealth of Late Pleistocene archaeology that exists across southern Africa’s open landscape, it is routinely neglected in favour of rock shelter (re)excavation, biasing interpretation of human–environment interaction. This is compounded by the scarcity of open-air studies that use geoarchaeological methods to investigate the history and processes involved in their formation. The open-air archaeology of the Doring River Valley is an example of this, despite nearly a decade of dedicated study and publication. Consequently, there remains a limited and untested understanding of the valley’s formation history. This paper rectifies this by providing a sedimentary context for the surface archaeology exposed across one of the Doring River Valley’s artefact-baring localities, Uitspankraal 7 (UPK7). Characterisation, particle size, mineralogical, morphometric, and geophysical analysis of UPK7′s sand mantle resulted in the identification of four artefact-bearing sedimentary units, the aeolian and pedogenic processes involved in their formation, and their proposed order of deposition. This provides a stratigraphic, taphonomic, and environmental context against which chronometric dating and an analysis of the taphonomic, spatio-temporal, and technological composition of UPK7′s surface archaeology can be compared. This work is the first vital step towards understanding the depositional and behavioural history of a landscape, irrespective of context type.
{"title":"The Sedimentary Context of Open-Air Archaeology: A Case Study in the Western Cape’s Doring River Valley, South Africa","authors":"N. Phillips, I. Moffat, A. Mackay, B. G. Jones","doi":"10.3390/soilsystems7010025","DOIUrl":"https://doi.org/10.3390/soilsystems7010025","url":null,"abstract":"Despite the wealth of Late Pleistocene archaeology that exists across southern Africa’s open landscape, it is routinely neglected in favour of rock shelter (re)excavation, biasing interpretation of human–environment interaction. This is compounded by the scarcity of open-air studies that use geoarchaeological methods to investigate the history and processes involved in their formation. The open-air archaeology of the Doring River Valley is an example of this, despite nearly a decade of dedicated study and publication. Consequently, there remains a limited and untested understanding of the valley’s formation history. This paper rectifies this by providing a sedimentary context for the surface archaeology exposed across one of the Doring River Valley’s artefact-baring localities, Uitspankraal 7 (UPK7). Characterisation, particle size, mineralogical, morphometric, and geophysical analysis of UPK7′s sand mantle resulted in the identification of four artefact-bearing sedimentary units, the aeolian and pedogenic processes involved in their formation, and their proposed order of deposition. This provides a stratigraphic, taphonomic, and environmental context against which chronometric dating and an analysis of the taphonomic, spatio-temporal, and technological composition of UPK7′s surface archaeology can be compared. This work is the first vital step towards understanding the depositional and behavioural history of a landscape, irrespective of context type.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42159001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-10DOI: 10.3390/soilsystems7010024
Shauna L. McLoughlin, R. Pattrick, J. Mosselmans, Joe Kelleher, B. V. van Dongen
The agricultural soils of West Limerick, Ireland, contain very localised, extremely high natural Se concentrations that reach levels that are very toxic to grazing livestock. The Carboniferous shales that formed in anoxic deep-water marine environments are the source of the selenium, which, along with the other redox-sensitive elements of molybdenum, uranium, arsenic and vanadium, were mobilised and reprecipitated in post-glacial anoxic marshes. The result has been a history of selenosis and molybdenosis in livestock in this important dairy province. Soils collected at 10–20 cm from five different agricultural sites were analysed, and all yielded concentrations greatly in excess of the safe Se limits of 3–10 mg kg−1; the highest value recorded was 1265.8 mg kg−1 Se. The highest recorded value for Mo in these soils was 1627.5 mg kg−1, and for U, 658.8 mg kg−1. There was a positive correlation between Se, Mo U and organic matter in the soils. Analysis of non-accumulator pasture grasses (Lolium perenne (perennial ryegrass), Festuca arundinacea (tall fescue), Dactylis glomerata (cocksfoot) and Phleum pretense (timothy grass)) revealed the shoot/leaf to contain up to 78.05 mg kg−1 Se while Trifolium repens (white clover) leaves contained 296.15 mg kg−1 Se. An in situ growing experiment using the Se accumulator species Brassica oleracea revealed 971.2 mg kg−1 Se in the leaves of premier kale, which also contained 1000.4 mg kg−1 Mo. Translocation factors (TFs) were generally higher for Mo than Se across all plant species. Combined X-ray absorption near edge spectroscopy (XANES) with micro-X-ray fluorescence (μ-XRF) showed the Se was present in the soil predominantly as the reduced immobile phase, elemental Se (Se0), but also as bioavailable organoselenium species, mainly selenomethionine (SeMet). SeMet was also the main species identified within both the Se non-accumulator and Se accumulator plants. The Se soil–plant system in West Limerick is dominated by SeMet, and uptake into the cattle pasture results in selenosis in the grazing dairy herds. The hyperaccumulating Brassica oleracea species could be used to extract both the Se and Mo to reduce the toxicity of the blighted fields.
{"title":"Selenium Uptake from Livestock Pasture Extremely Enriched in Selenium, Molybdenum and Uranium: A Field and X-ray Absorption Study","authors":"Shauna L. McLoughlin, R. Pattrick, J. Mosselmans, Joe Kelleher, B. V. van Dongen","doi":"10.3390/soilsystems7010024","DOIUrl":"https://doi.org/10.3390/soilsystems7010024","url":null,"abstract":"The agricultural soils of West Limerick, Ireland, contain very localised, extremely high natural Se concentrations that reach levels that are very toxic to grazing livestock. The Carboniferous shales that formed in anoxic deep-water marine environments are the source of the selenium, which, along with the other redox-sensitive elements of molybdenum, uranium, arsenic and vanadium, were mobilised and reprecipitated in post-glacial anoxic marshes. The result has been a history of selenosis and molybdenosis in livestock in this important dairy province. Soils collected at 10–20 cm from five different agricultural sites were analysed, and all yielded concentrations greatly in excess of the safe Se limits of 3–10 mg kg−1; the highest value recorded was 1265.8 mg kg−1 Se. The highest recorded value for Mo in these soils was 1627.5 mg kg−1, and for U, 658.8 mg kg−1. There was a positive correlation between Se, Mo U and organic matter in the soils. Analysis of non-accumulator pasture grasses (Lolium perenne (perennial ryegrass), Festuca arundinacea (tall fescue), Dactylis glomerata (cocksfoot) and Phleum pretense (timothy grass)) revealed the shoot/leaf to contain up to 78.05 mg kg−1 Se while Trifolium repens (white clover) leaves contained 296.15 mg kg−1 Se. An in situ growing experiment using the Se accumulator species Brassica oleracea revealed 971.2 mg kg−1 Se in the leaves of premier kale, which also contained 1000.4 mg kg−1 Mo. Translocation factors (TFs) were generally higher for Mo than Se across all plant species. Combined X-ray absorption near edge spectroscopy (XANES) with micro-X-ray fluorescence (μ-XRF) showed the Se was present in the soil predominantly as the reduced immobile phase, elemental Se (Se0), but also as bioavailable organoselenium species, mainly selenomethionine (SeMet). SeMet was also the main species identified within both the Se non-accumulator and Se accumulator plants. The Se soil–plant system in West Limerick is dominated by SeMet, and uptake into the cattle pasture results in selenosis in the grazing dairy herds. The hyperaccumulating Brassica oleracea species could be used to extract both the Se and Mo to reduce the toxicity of the blighted fields.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44800393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-09DOI: 10.3390/soilsystems7010023
Julius Albert, Camilla More, S. Korz, K. Muñoz
Aflatoxins (AFs) are fungal secondary metabolites frequently detected in soil that exhibit in vitro toxicity to certain soil microorganisms. However, microbial responses at different levels and in complex systems such as the soil environment have not been systematically studied. Therefore, we investigated multiple microbial responses in two different soils (sandy loam and clay) to aflatoxin B1 (AFB1) at environmentally relevant concentrations (0.5–500 µg kg−1) during a 28-day incubation. General microbial parameters for biomass (microbial biomass carbon and ergosterol), activity (glucose-induced and basal respiration), and catabolic functionality (substrate utilization patterns) were assessed. We observed minor and transient effects in both soils. In sandy loam, we found negative effects on activity and catabolic functionality with increased metabolic quotient, while clay soil exhibited stimulation for the same parameters, suggesting a hormetic effect due to reduced bioavailability through sorption onto clay minerals. Our results indicate that AFB1 does not pose a threat to general microbial indicators under the test conditions in soils without previous AF contamination. Given the toxic potential of AFs to specific microorganisms, further studies should investigate responses at higher taxonomic and functional levels in natural environments of aflatoxigenic fungi, such as tropical soils, and including additional physicochemical stressors.
{"title":"Soil Microbial Responses to Aflatoxin Exposure: Consequences for Biomass, Activity and Catabolic Functionality","authors":"Julius Albert, Camilla More, S. Korz, K. Muñoz","doi":"10.3390/soilsystems7010023","DOIUrl":"https://doi.org/10.3390/soilsystems7010023","url":null,"abstract":"Aflatoxins (AFs) are fungal secondary metabolites frequently detected in soil that exhibit in vitro toxicity to certain soil microorganisms. However, microbial responses at different levels and in complex systems such as the soil environment have not been systematically studied. Therefore, we investigated multiple microbial responses in two different soils (sandy loam and clay) to aflatoxin B1 (AFB1) at environmentally relevant concentrations (0.5–500 µg kg−1) during a 28-day incubation. General microbial parameters for biomass (microbial biomass carbon and ergosterol), activity (glucose-induced and basal respiration), and catabolic functionality (substrate utilization patterns) were assessed. We observed minor and transient effects in both soils. In sandy loam, we found negative effects on activity and catabolic functionality with increased metabolic quotient, while clay soil exhibited stimulation for the same parameters, suggesting a hormetic effect due to reduced bioavailability through sorption onto clay minerals. Our results indicate that AFB1 does not pose a threat to general microbial indicators under the test conditions in soils without previous AF contamination. Given the toxic potential of AFs to specific microorganisms, further studies should investigate responses at higher taxonomic and functional levels in natural environments of aflatoxigenic fungi, such as tropical soils, and including additional physicochemical stressors.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48086140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-02DOI: 10.3390/soilsystems7010021
D. Antille, Ben C. T. Macdonald, Aleni Uelese, M. Webb, Jennifer Kelly, S. Tauati, U. Stockmann, Jeda Palmer, J. Barringer
A progressive decline in soil fertility in taro (Colocasia esculenta L., Schott) production systems has contributed to reduced crop productivity and farm profitability, and is recognized to be a threat to soil nutrient and food security in Samoa. Evidence based on three years of field experimentation showed that appropriate nutrient budgeting is required to reduce soil nutrient deficits and mitigate soil organic carbon loss. Balanced crop nutrition coupled with appropriate crop husbandry can significantly improve productivity and narrow yield gaps. A framework to guide nutrient recommendations for taro production systems is presented and discussed. This framework proposes that recommendations for N be derived from the yield-to-N response function (from which the most economic rate of N can be estimated) and that for other nutrients, namely P, K, Ca, and Mg, recommendations be based on replacement. The replacement strategy requires the development of soil nutrient indexes, which can be used to define the long-term nutrient management policy at the field scale. This long-term policy is informed by soil analyses, and it will determine whether existing soil nutrient levels are to be maintained or increased depending on the focus (productivity, profitability, environmental protection). If soil nutrients were already at an agronomically satisfactory level, their application may be omitted in some years to help reduce crop production costs, improve use efficiency, and ensure environmentally safe levels in soil are not exceeded.
{"title":"Toward Soil Nutrient Security for Improved Agronomic Performance and Increased Resilience of Taro Production Systems in Samoa","authors":"D. Antille, Ben C. T. Macdonald, Aleni Uelese, M. Webb, Jennifer Kelly, S. Tauati, U. Stockmann, Jeda Palmer, J. Barringer","doi":"10.3390/soilsystems7010021","DOIUrl":"https://doi.org/10.3390/soilsystems7010021","url":null,"abstract":"A progressive decline in soil fertility in taro (Colocasia esculenta L., Schott) production systems has contributed to reduced crop productivity and farm profitability, and is recognized to be a threat to soil nutrient and food security in Samoa. Evidence based on three years of field experimentation showed that appropriate nutrient budgeting is required to reduce soil nutrient deficits and mitigate soil organic carbon loss. Balanced crop nutrition coupled with appropriate crop husbandry can significantly improve productivity and narrow yield gaps. A framework to guide nutrient recommendations for taro production systems is presented and discussed. This framework proposes that recommendations for N be derived from the yield-to-N response function (from which the most economic rate of N can be estimated) and that for other nutrients, namely P, K, Ca, and Mg, recommendations be based on replacement. The replacement strategy requires the development of soil nutrient indexes, which can be used to define the long-term nutrient management policy at the field scale. This long-term policy is informed by soil analyses, and it will determine whether existing soil nutrient levels are to be maintained or increased depending on the focus (productivity, profitability, environmental protection). If soil nutrients were already at an agronomically satisfactory level, their application may be omitted in some years to help reduce crop production costs, improve use efficiency, and ensure environmentally safe levels in soil are not exceeded.","PeriodicalId":21908,"journal":{"name":"Soil Systems","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44616208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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