Pub Date : 2023-02-02DOI: 10.3389/fsoil.2023.1010677
Xue Li, Na Li, Jinfeng Yang, Yanan Xiang, Xin Wang, Xiao Han
Introduction To comprehend soil P transformation and crop P uptake, it is necessary to understand how the long-term substitution of mineral fertilizers with stover or biochar affects soil properties and P forms. However, the effects of large-scale continuous stover or biochar application on soil P forms and fractions and the response of P uptake by corn are largely unknown. The purpose of this study was to investigate the role of stover and its biochar in the variation of P forms and Hedley-P fractions. Methods A five-year field experiment in brown soil was carried out using the following treatments: non-fertilizer (CK), chemical fertilizer (NPK), chemical fertilizer + corn stover (SNPK), and chemical fertilizer + biochar (CNPK). Hedley fractionation and 31P nuclear magnetic resonance spectroscopy were used to determine P compounds. Results and discussion The greatest increases in P uptake occurred during the CNPK treatment, specifically orthophosphate and Resin-P, and coincided with increases in total inorganic P and Hedley-P fractions. On the other hand, total organic P accumulation was found to be highest in the SNPK treatment, as was total inositol hexakisphosphate and orthophosphate diester accumulation. Treatments with SNPK and CNPK significantly increased adenosine monophosphate and DNA. However, no difference was found between NaHCO3-Pi and NaOH-Pi of the NPK, SNPK, and CNPK treatments. Decreasing chemical fertilizer and partially replacing it with biochar in brown soil may increase crop P uptake by degrading applied organic P forms and multiplying inorganic P forms.
{"title":"Changes in P forms and fractions due to the addition of stover and biochar to growing crops in soils amended with stover and its biochar","authors":"Xue Li, Na Li, Jinfeng Yang, Yanan Xiang, Xin Wang, Xiao Han","doi":"10.3389/fsoil.2023.1010677","DOIUrl":"https://doi.org/10.3389/fsoil.2023.1010677","url":null,"abstract":"Introduction To comprehend soil P transformation and crop P uptake, it is necessary to understand how the long-term substitution of mineral fertilizers with stover or biochar affects soil properties and P forms. However, the effects of large-scale continuous stover or biochar application on soil P forms and fractions and the response of P uptake by corn are largely unknown. The purpose of this study was to investigate the role of stover and its biochar in the variation of P forms and Hedley-P fractions. Methods A five-year field experiment in brown soil was carried out using the following treatments: non-fertilizer (CK), chemical fertilizer (NPK), chemical fertilizer + corn stover (SNPK), and chemical fertilizer + biochar (CNPK). Hedley fractionation and 31P nuclear magnetic resonance spectroscopy were used to determine P compounds. Results and discussion The greatest increases in P uptake occurred during the CNPK treatment, specifically orthophosphate and Resin-P, and coincided with increases in total inorganic P and Hedley-P fractions. On the other hand, total organic P accumulation was found to be highest in the SNPK treatment, as was total inositol hexakisphosphate and orthophosphate diester accumulation. Treatments with SNPK and CNPK significantly increased adenosine monophosphate and DNA. However, no difference was found between NaHCO3-Pi and NaOH-Pi of the NPK, SNPK, and CNPK treatments. Decreasing chemical fertilizer and partially replacing it with biochar in brown soil may increase crop P uptake by degrading applied organic P forms and multiplying inorganic P forms.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47248474","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 : 2023-01-31DOI: 10.3389/fsoil.2023.1090145
L. Gomes, A. Beucher, A. B. Møller, B. V. Iversen, C. D. Børgesen, Diana Vigah Adetsu, Gasper L. Sechu, G. Heckrath, J. Koch, K. Adhikari, M. Knadel, M. Lamandé, M. Greve, N. H. Jensen, Sebastian Gutierrez, Thomas Balstrøm, T. Koganti, Yannik E. Roell, Yi Peng, M. Greve
Soil provides essential ecosystem services sustaining and improving human life, but mapping soil functions is an ongoing challenge. Denmark has a long history of carrying out soil assessments − originally in order to determine tax revenues for the king, and, more recently, for aiding policymakers and farmers. This knowledge has supported the development of intensive agricultural systems while maintaining the provision of ecosystem services (e.g., clean water). Getting an overview of historical soil surveys and pedological mapping approaches can generate useful information for mapping soil, identifying gaps and proposing directions for future research. In this review, we explore the evolution of soil and environmental inventories, the historical development of soil mapping methods, and how these factors contributed to a better spatial understanding of soil functions. Specifically, we discuss soil functions related to water regulation (e.g., drainage, groundwater and water surface interactions, water table), water filtering (e.g., nitrogen leaching), carbon sequestration (e.g., peatlands), agricultural production (e.g., land suitability, wheat yields), and threats related to soil degradation (e.g., soil erosion). Denmark has benefitted from a government-coordinated approach, promoting detailed and systematic national soil surveys and environmental monitoring programmes. The large databases produced in the surveys formed the basis for mapping several soil properties and functions at increasingly high resolutions over the last many years based on developments in machine learning. In contrast to methodological advances in soil mapping and relevant contributions to pedometric research, we identified a lack of spatial information on soil biodiversity. Detailed spatial information about soil functions is essential to address global issues, such as climate change, food security and water security, and the experience of mapping soil functions in Denmark can be a source of inspiration to other parts of the world.
{"title":"Soil assessment in Denmark: Towards soil functional mapping and beyond","authors":"L. Gomes, A. Beucher, A. B. Møller, B. V. Iversen, C. D. Børgesen, Diana Vigah Adetsu, Gasper L. Sechu, G. Heckrath, J. Koch, K. Adhikari, M. Knadel, M. Lamandé, M. Greve, N. H. Jensen, Sebastian Gutierrez, Thomas Balstrøm, T. Koganti, Yannik E. Roell, Yi Peng, M. Greve","doi":"10.3389/fsoil.2023.1090145","DOIUrl":"https://doi.org/10.3389/fsoil.2023.1090145","url":null,"abstract":"Soil provides essential ecosystem services sustaining and improving human life, but mapping soil functions is an ongoing challenge. Denmark has a long history of carrying out soil assessments − originally in order to determine tax revenues for the king, and, more recently, for aiding policymakers and farmers. This knowledge has supported the development of intensive agricultural systems while maintaining the provision of ecosystem services (e.g., clean water). Getting an overview of historical soil surveys and pedological mapping approaches can generate useful information for mapping soil, identifying gaps and proposing directions for future research. In this review, we explore the evolution of soil and environmental inventories, the historical development of soil mapping methods, and how these factors contributed to a better spatial understanding of soil functions. Specifically, we discuss soil functions related to water regulation (e.g., drainage, groundwater and water surface interactions, water table), water filtering (e.g., nitrogen leaching), carbon sequestration (e.g., peatlands), agricultural production (e.g., land suitability, wheat yields), and threats related to soil degradation (e.g., soil erosion). Denmark has benefitted from a government-coordinated approach, promoting detailed and systematic national soil surveys and environmental monitoring programmes. The large databases produced in the surveys formed the basis for mapping several soil properties and functions at increasingly high resolutions over the last many years based on developments in machine learning. In contrast to methodological advances in soil mapping and relevant contributions to pedometric research, we identified a lack of spatial information on soil biodiversity. Detailed spatial information about soil functions is essential to address global issues, such as climate change, food security and water security, and the experience of mapping soil functions in Denmark can be a source of inspiration to other parts of the world.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46907247","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 : 2023-01-24DOI: 10.3389/fsoil.2023.1066547
Antonio Junior, M. Guo
Converting sewage sludge to biochar to serve as soil amendment and nutrient supplement to cropland may be an environmental benign and value-added approach to recycle the waste. Potting experiments were conducted to examine the efficacy of sludge biochar amendments on enhancing soil health and crop productivity. Strongly acidic soil (pH=5.0) was amended with sludge biochar at three different concentrations: 0 (control), 1% and 2% of its dry weight, and packed into plastic buckets (9.45-L) to a bulk density of 1.1 g cm-3, and each treatment had three replicates. Winter wheat (Triticum aestivum L.), spinach (Spinacia oleracea), and Mung bean (Vigna radiata) were sequentially grown for nine months under greenhouse and field conditions (each crop cycle lasted three months). The above-ground biomass was collected, and oven dried at 65°C for 72 hours to assess plant biomass yield. Soil health parameters such as aggregates stability, pH, electric conductivity (EC), soil respiration, and microbial biomass C were measured. Soils amended with 2% biochar demonstrated higher biomass yield in winter wheat and spinach crops compared to those amended with 1% biochar and unamended control, on the other hand, mung bean did not present significant difference in all treatments. Similarly, 2% biochar demonstrated high aggregates stability (19.85%) followed by control (9%) and 1% biochar (8.3%). Soil acidity was neutralized in soils amended with 2% biochar (pH: 6.5) compared to control (pH: 5.8) and 1% biochar (pH: 5.5). EC was in the ideal level (<2.7 dS m-1) for all treatments. Soil respiration was not significantly different in all treatments. Microbial biomass C was higher in control and 2% biochar with significant differences towards 1% biochar. These findings provide additional evidence that sludge biochar promote plant growth and improve certain soil health parameters. However, the effect of sludge biochar in soil biological properties was not observed. Therefore, long-term field experiments are needed to assess the amendment effect of sludge biochar on microbial biomass C and soil respiration to validate the persistent efficacy of sludge biochar amendments on facilitating crop production, crop productivity, and soil health.
{"title":"Efficacy of sewage sludge derived biochar on enhancing soil health and crop productivity in strongly acidic soil","authors":"Antonio Junior, M. Guo","doi":"10.3389/fsoil.2023.1066547","DOIUrl":"https://doi.org/10.3389/fsoil.2023.1066547","url":null,"abstract":"Converting sewage sludge to biochar to serve as soil amendment and nutrient supplement to cropland may be an environmental benign and value-added approach to recycle the waste. Potting experiments were conducted to examine the efficacy of sludge biochar amendments on enhancing soil health and crop productivity. Strongly acidic soil (pH=5.0) was amended with sludge biochar at three different concentrations: 0 (control), 1% and 2% of its dry weight, and packed into plastic buckets (9.45-L) to a bulk density of 1.1 g cm-3, and each treatment had three replicates. Winter wheat (Triticum aestivum L.), spinach (Spinacia oleracea), and Mung bean (Vigna radiata) were sequentially grown for nine months under greenhouse and field conditions (each crop cycle lasted three months). The above-ground biomass was collected, and oven dried at 65°C for 72 hours to assess plant biomass yield. Soil health parameters such as aggregates stability, pH, electric conductivity (EC), soil respiration, and microbial biomass C were measured. Soils amended with 2% biochar demonstrated higher biomass yield in winter wheat and spinach crops compared to those amended with 1% biochar and unamended control, on the other hand, mung bean did not present significant difference in all treatments. Similarly, 2% biochar demonstrated high aggregates stability (19.85%) followed by control (9%) and 1% biochar (8.3%). Soil acidity was neutralized in soils amended with 2% biochar (pH: 6.5) compared to control (pH: 5.8) and 1% biochar (pH: 5.5). EC was in the ideal level (<2.7 dS m-1) for all treatments. Soil respiration was not significantly different in all treatments. Microbial biomass C was higher in control and 2% biochar with significant differences towards 1% biochar. These findings provide additional evidence that sludge biochar promote plant growth and improve certain soil health parameters. However, the effect of sludge biochar in soil biological properties was not observed. Therefore, long-term field experiments are needed to assess the amendment effect of sludge biochar on microbial biomass C and soil respiration to validate the persistent efficacy of sludge biochar amendments on facilitating crop production, crop productivity, and soil health.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43955124","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 : 2023-01-19DOI: 10.3389/fsoil.2022.941837
F. Radford, A. Horton, M. Hudson, Peter Shaw, I. Williams
Biosolids are the solid by-product of the wastewater treatment system. They are regularly applied to agricultural land in the UK to fertilize and increase crop yields, but they have been shown to contain high concentrations of microplastics. Here we sampled a selection of agricultural soils in the Southeast of England which had received or never received biosolid treatment. Sites were sampled on two occasions in the summer and winter. Microplastic (MP) numbers were high in both the biosolid treated fields (874 MP/kg) and the untreated fields (664 MP/kg) and a wide variety of polymers were found across sites. However, there was a lack of significant difference between treated and untreated soils. This suggests the influence of other microplastic sources e.g. agricultural plastic and general littering, and external conditions e.g. farm management and rainfall. Microplastic concentrations were higher in the summer suggesting that erosion, runoff, and wind transport may be removing microplastics from these systems. The dynamic nature of the agricultural soils may result in them becoming a vector for microplastics into the wider environment. The high variability in results seen here highlights the complexity of microplastic concentrations in heterogeneous agricultural soils. This study suggests that biosolids, whilst are likely a contributor, are not the sole source of microplastics in agricultural soils. Further research is required to determine source and sink dynamics in these systems. Understanding the sources of microplastic contamination in soils is imperative for future mitigation strategies to be effective.
{"title":"Agricultural soils and microplastics: Are biosolids the problem?","authors":"F. Radford, A. Horton, M. Hudson, Peter Shaw, I. Williams","doi":"10.3389/fsoil.2022.941837","DOIUrl":"https://doi.org/10.3389/fsoil.2022.941837","url":null,"abstract":"Biosolids are the solid by-product of the wastewater treatment system. They are regularly applied to agricultural land in the UK to fertilize and increase crop yields, but they have been shown to contain high concentrations of microplastics. Here we sampled a selection of agricultural soils in the Southeast of England which had received or never received biosolid treatment. Sites were sampled on two occasions in the summer and winter. Microplastic (MP) numbers were high in both the biosolid treated fields (874 MP/kg) and the untreated fields (664 MP/kg) and a wide variety of polymers were found across sites. However, there was a lack of significant difference between treated and untreated soils. This suggests the influence of other microplastic sources e.g. agricultural plastic and general littering, and external conditions e.g. farm management and rainfall. Microplastic concentrations were higher in the summer suggesting that erosion, runoff, and wind transport may be removing microplastics from these systems. The dynamic nature of the agricultural soils may result in them becoming a vector for microplastics into the wider environment. The high variability in results seen here highlights the complexity of microplastic concentrations in heterogeneous agricultural soils. This study suggests that biosolids, whilst are likely a contributor, are not the sole source of microplastics in agricultural soils. Further research is required to determine source and sink dynamics in these systems. Understanding the sources of microplastic contamination in soils is imperative for future mitigation strategies to be effective.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49100750","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 : 2023-01-12DOI: 10.3389/fsoil.2022.1101944
H. Tindwa, Bal R Singh
The sub-Saharan Africa (SSA) region bears the blunt of soil pollution mainly due to-haphazard disposal and gross mismanagement of a wide assortment of pollutants generated from within and outside the region. Pollution of agricultural soils in the region is so intense that out of the 80 countries substantially affected by land degradation (soil pollution, inclusive) in the world, 36 are found in Africa, the SSA, in particular. Pollution of soils has resulted into a significant reduction in their ability to support crop growth and yield apart from jeopardizing safety and security of agricultural produce in SSA. Consequences of pollution of soils on human health in the region are inadequately reported, but they range from non-fatal, life-changing effects like skin damage due to acute, invariably fatal incidences of exposure to milt by chronic effects. We show in this review, that while science and advancement in technology has provided a multitude of alternative techniques to pollution control and remediation of affected soils, such techniques are largely inaccessible to most SSA countries. There is also lack of coordination on development, enforcement and implementation of legal and political instruments to tackle the growing risk of pollution to human health from soil contamination across the SSA region. Couple with this, lack of data on status of soil pollution in most SSA countries affects the countries’ capacity to devise and plan policies that can help reduce soil pollution. Countries need to maximize efforts to reverse the status of already polluted pieces of land through strengthening remediation programs, research on how best to gather, maintain and complement soil pollution data and actions that inform decision-making.
{"title":"Soil pollution and agriculture in sub-Saharan Africa: State of the knowledge and remediation technologies","authors":"H. Tindwa, Bal R Singh","doi":"10.3389/fsoil.2022.1101944","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1101944","url":null,"abstract":"The sub-Saharan Africa (SSA) region bears the blunt of soil pollution mainly due to-haphazard disposal and gross mismanagement of a wide assortment of pollutants generated from within and outside the region. Pollution of agricultural soils in the region is so intense that out of the 80 countries substantially affected by land degradation (soil pollution, inclusive) in the world, 36 are found in Africa, the SSA, in particular. Pollution of soils has resulted into a significant reduction in their ability to support crop growth and yield apart from jeopardizing safety and security of agricultural produce in SSA. Consequences of pollution of soils on human health in the region are inadequately reported, but they range from non-fatal, life-changing effects like skin damage due to acute, invariably fatal incidences of exposure to milt by chronic effects. We show in this review, that while science and advancement in technology has provided a multitude of alternative techniques to pollution control and remediation of affected soils, such techniques are largely inaccessible to most SSA countries. There is also lack of coordination on development, enforcement and implementation of legal and political instruments to tackle the growing risk of pollution to human health from soil contamination across the SSA region. Couple with this, lack of data on status of soil pollution in most SSA countries affects the countries’ capacity to devise and plan policies that can help reduce soil pollution. Countries need to maximize efforts to reverse the status of already polluted pieces of land through strengthening remediation programs, research on how best to gather, maintain and complement soil pollution data and actions that inform decision-making.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44784296","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 : 2023-01-12DOI: 10.3389/fsoil.2022.1048057
Arcadius Martinien Agassin Ahogle, S. Letema, G. Schaab, V. Ngure, Abraham R. Mwesigye, N. Korir
Introduction With urbanization and industrialization in the developing world, urban and peri-urban agriculture is increasingly contributing to urban food systems, employment, and income generation opportunities. However, urbanization and industrialization may release harmful pollutants, including heavy metals and trace elements into agricultural soils, posing ecological, environmental and public health concerns. This paper assessed the potential risks of soil contamination with heavy metals and trace elements in peri-urban farmlands in Nairobi city catchment in Kenya. Methods A total of 60 soil samples were collected from ten vegetable farming zones (S1-S10) and processed following standard protocols. The concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn were analyzed in the samples using inductively coupled plasma-mass spectrometry (ICP-MS). Results and discussion Results revealed that the soil samples have elevated concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn, with some elements including As (1.7%), Cd (13.3%), Mn (80%), Pb (1.7%) and Zn (11.7%) exceeding the permissible thresholds for agricultural soils. The spatial distribution of the elements exhibited three similar distribution patterns with slight variations between the hotspot sites of the different elements: (i) Co and Mn, (ii) Cu and Cr and (iii) As, Cd, Fe, Hg, Pb and Zn, while Ni and V exhibited singular spatial distributions compared to other elements. Elements such as As, Cd, Co, Fe, Hg, Mn, Pb and Zn appeared to be of anthropogenic enrichment, while Cr, Cu, Ni and V appeared to originate mainly from lithogenic and natural sources. The elements As, Cd, Hg and Pb exhibited high ecological risks, with Cd contributing about 46-66% of the overall ecological risk. The sampling sites S1, S5, S7, S9 and S10 depicted the highest ecological risks of 145, 103, 146, 121 and 146, respectively. The findings call for proper zoning of suitable agricultural areas and sound waste management protocols in urban and peri-urban landscapes. Further, remediation of contaminated soils and farmers’ sensitization are recommended for ecological and public health risk alleviation.
{"title":"Heavy metals and trace elements contamination risks in peri-urban agricultural soils in Nairobi city catchment, Kenya","authors":"Arcadius Martinien Agassin Ahogle, S. Letema, G. Schaab, V. Ngure, Abraham R. Mwesigye, N. Korir","doi":"10.3389/fsoil.2022.1048057","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1048057","url":null,"abstract":"Introduction With urbanization and industrialization in the developing world, urban and peri-urban agriculture is increasingly contributing to urban food systems, employment, and income generation opportunities. However, urbanization and industrialization may release harmful pollutants, including heavy metals and trace elements into agricultural soils, posing ecological, environmental and public health concerns. This paper assessed the potential risks of soil contamination with heavy metals and trace elements in peri-urban farmlands in Nairobi city catchment in Kenya. Methods A total of 60 soil samples were collected from ten vegetable farming zones (S1-S10) and processed following standard protocols. The concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn were analyzed in the samples using inductively coupled plasma-mass spectrometry (ICP-MS). Results and discussion Results revealed that the soil samples have elevated concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn, with some elements including As (1.7%), Cd (13.3%), Mn (80%), Pb (1.7%) and Zn (11.7%) exceeding the permissible thresholds for agricultural soils. The spatial distribution of the elements exhibited three similar distribution patterns with slight variations between the hotspot sites of the different elements: (i) Co and Mn, (ii) Cu and Cr and (iii) As, Cd, Fe, Hg, Pb and Zn, while Ni and V exhibited singular spatial distributions compared to other elements. Elements such as As, Cd, Co, Fe, Hg, Mn, Pb and Zn appeared to be of anthropogenic enrichment, while Cr, Cu, Ni and V appeared to originate mainly from lithogenic and natural sources. The elements As, Cd, Hg and Pb exhibited high ecological risks, with Cd contributing about 46-66% of the overall ecological risk. The sampling sites S1, S5, S7, S9 and S10 depicted the highest ecological risks of 145, 103, 146, 121 and 146, respectively. The findings call for proper zoning of suitable agricultural areas and sound waste management protocols in urban and peri-urban landscapes. Further, remediation of contaminated soils and farmers’ sensitization are recommended for ecological and public health risk alleviation.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47926865","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 : 2023-01-10DOI: 10.3389/fsoil.2022.1050779
M. McDonald, Katie L. Lewis, P. DeLaune, Brian A. Hux, T. Boutton, T. Gentry
Introduction Nitrous oxide (N2O) emission from soil is a major concern due to its contribution to global climate change and its function as a loss mechanism of plant-available nitrogen (N) from the soil. This is especially true in intensive agricultural soils with high rates of N fertilizer application such as those on the semi-arid Southern High Plains, USA. Methods This study examined emissions of N2O, pore-space concentrations of N2O and nitric oxide (NO), soil chemical properties, water content, and the genetic potential for N cycling five years after conservation system and N management implementation. Results For these semi-arid soils with low N, carbon, and water contents, large soil N2O emissions (up to 8 mL N2O-N m-2 day-1) are directly related to the application of N fertilizer which overwhelms the N2O reducing capacity of the soil. When this fertilizer N is depleted, N2O flux is either low, non-existent, or net-negative and has been observed as early as mid-season for preplant applied N fertilizer (-0.1 mL N2O-N m-2 day-1). Soil pore-space gas concentrations (N2O and NO) remained relatively constant across the growing season (average N2O: 0.78 µL N2O L-1 soil air; NO: 3.3 µL NO L-1 soil air, indicating a base-level of N-cycle activity, but was not directly related to surface emissions of N2O which decreased across the growing season. In addition, genetic potential for N cycle activities increased across the growing season simultaneously with stagnant/reduced N cycle activity. This reflects the difficulty in relating genetic potential to in-situ activity in field research. Conclusion It is likely that in a nutrient and carbon-poor soil, such as the semi-arid agricultural soil in this study, the microbial processes associated with N cycling are mostly limited by inorganic-N and less directly related to genetic potential at the time of sampling.
土壤中氧化亚氮(N2O)的排放对全球气候变化的贡献及其作为土壤中植物有效氮(N)损失机制的功能是一个主要问题。这在密集的农业土壤中尤其如此，氮肥的施用率很高，如美国半干旱的南部高平原。方法本研究考察了土壤N2O排放量、N2O和一氧化氮(NO)孔隙浓度、土壤化学性质、水分含量以及实施保护系统和氮素管理后5年氮素循环的遗传潜力。结果在低氮、低碳、低含水量的半干旱土壤中，大量的N2O排放(高达8 mL N2O-N m-2 day-1)与施用氮肥超过土壤的N2O还原能力直接相关。当氮肥耗尽时，N2O通量要么很低，要么不存在，要么是净负的，早在种植前施用氮肥的季节中期就观察到(-0.1 mL N2O-N m-2 day-1)。土壤孔隙空间气体浓度(N2O和NO)在整个生长季节保持相对恒定(平均N2O: 0.78µL N2O -1土壤空气;NO: 3.3µL NO L-1土壤空气，表明氮循环活动的基本水平，但与N2O的地表排放没有直接关系，N2O在整个生长季节减少。此外，氮素循环活性的遗传潜力在整个生长季节增加，同时氮素循环活性停滞或降低。这反映了在野外研究中将遗传潜力与现场活动联系起来的困难。结论在养分和碳贫乏的土壤中，如本研究的半干旱农业土壤，与N循环相关的微生物过程可能主要受到无机氮的限制，而与采样时的遗传势的直接关系较少。
{"title":"Nitrogen fertilizer driven nitrous and nitric oxide production is decoupled from microbial genetic potential in low carbon, semi-arid soil","authors":"M. McDonald, Katie L. Lewis, P. DeLaune, Brian A. Hux, T. Boutton, T. Gentry","doi":"10.3389/fsoil.2022.1050779","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1050779","url":null,"abstract":"Introduction Nitrous oxide (N2O) emission from soil is a major concern due to its contribution to global climate change and its function as a loss mechanism of plant-available nitrogen (N) from the soil. This is especially true in intensive agricultural soils with high rates of N fertilizer application such as those on the semi-arid Southern High Plains, USA. Methods This study examined emissions of N2O, pore-space concentrations of N2O and nitric oxide (NO), soil chemical properties, water content, and the genetic potential for N cycling five years after conservation system and N management implementation. Results For these semi-arid soils with low N, carbon, and water contents, large soil N2O emissions (up to 8 mL N2O-N m-2 day-1) are directly related to the application of N fertilizer which overwhelms the N2O reducing capacity of the soil. When this fertilizer N is depleted, N2O flux is either low, non-existent, or net-negative and has been observed as early as mid-season for preplant applied N fertilizer (-0.1 mL N2O-N m-2 day-1). Soil pore-space gas concentrations (N2O and NO) remained relatively constant across the growing season (average N2O: 0.78 µL N2O L-1 soil air; NO: 3.3 µL NO L-1 soil air, indicating a base-level of N-cycle activity, but was not directly related to surface emissions of N2O which decreased across the growing season. In addition, genetic potential for N cycle activities increased across the growing season simultaneously with stagnant/reduced N cycle activity. This reflects the difficulty in relating genetic potential to in-situ activity in field research. Conclusion It is likely that in a nutrient and carbon-poor soil, such as the semi-arid agricultural soil in this study, the microbial processes associated with N cycling are mostly limited by inorganic-N and less directly related to genetic potential at the time of sampling.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45947815","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 : 2023-01-10DOI: 10.3389/fsoil.2022.1082940
Xueming Yang, W. D. Reynolds, C. Drury, M. Reeb
Summer-seeding legume cover crops can reduce erosion, mitigate nitrate leaching losses during the non-growing season, and provide bio-accumulated nitrogen (N) to the following crop. Very little information is available, however, on the most effective methods for terminating summer-seeded cover crops, or on the amount of N they can provide to subsequent crops. We therefore evaluated the impacts of selected legume cover crops and cover crop termination-tillage methods on corn (Zea mays L.) N credit and grain yield in a soybean (Glycine max Merr.) - winter wheat (Triticum aestivum L.)/cover crop - corn rotation over 3 consecutive years on a clay loam soil in southwestern Ontario. The cover crops were summer-seeded after wheat harvest, and included hairy vetch (Vicia villosa L. Roth), red clover (Trifolium pratense L.), white clover plus crimson clover mix (incarnatum and Trifolium alba L.), and a no cover crop control (CK). The cover crops were nested within termination-tillage method, including moldboard plow-down in fall, and herbicide spray-down in spring under strip-tillage or no-tillage then corn planting. Nitrogen fertilizer to corn was applied via side-dress at 200 kg N ha-1 to the CKs, and at 100 kg N ha-1 to the cover crops. Averaged over 3 years, above-ground biomass N level followed the pattern: hairy vetch > white clover plus crimson clover mix > red clover for fall plow-down termination. There were no significant differences in cover crop biomass N levels for spring termination. Corn response to cover crop was significantly affected by termination-tillage method and cover crop species, with poor corn stands after no-tillage, red clover and white plus crimson clover. Fall plow-down termination provided a range in N credit of 80-85 kg N ha-1, which was significantly greater than the N credit under herbicide spray-down in spring. Under spring strip-tillage and no-tillage, hairy vetch produced significantly greater corn grain yields than red clover and white plus crimson clover mix.
夏季播种豆类覆盖作物可以减少侵蚀，减轻非生长季节的硝酸盐浸出损失，并为后续作物提供生物累积氮。然而，关于终止夏季播种覆盖作物的最有效方法，或者它们可以为后续作物提供的氮量，目前的信息很少。因此，我们在安大略省西南部的粘壤土上连续3年评估了选定的豆类覆盖作物和覆盖作物终止耕作方法对玉米（Zea mays L.）氮信用和大豆（Glycine max Merr.）-冬小麦（Triticum aestivum L.）/覆盖作物-玉米轮作的粮食产量的影响。覆盖作物在小麦收获后的夏季播种，包括毛茛（Vicia villosa L.Roth）、红三叶草（Trifolium pratense L.）、白三叶草加深红三叶草混合物（incarnatum和Trifolium alba L.）和无覆盖作物对照（CK）。覆盖作物嵌套在终止耕作法中，包括秋季犁板犁下，春季在带状耕作或免耕下喷洒除草剂，然后种植玉米。玉米施用的氮肥是通过侧覆施用的，CK施用200 kg N ha-1，覆盖作物施用100 kg N ha-。平均3年以上，地上生物量氮水平遵循以下模式：毛豌豆>白三叶草加深红三叶草混合物>红三叶草秋季播种终止。春季终止覆盖作物生物量氮水平没有显著差异。终止耕作方式和覆盖作物种类对玉米对覆盖作物的响应有显著影响，其中免耕后玉米林分较差，红三叶草和白三叶草加深红色三叶草。秋季犁耕终止提供了80-85 kg N ha-1的N信用范围，这显著大于春季喷洒除草剂时的N信用。在春季带状耕作和免耕条件下，毛豌豆的玉米产量明显高于红三叶草和白色加深红色三叶草的混合物。
{"title":"Impacts of summer-seeded legume cover crops and termination-tillage method on nitrogen availability to corn in rotation","authors":"Xueming Yang, W. D. Reynolds, C. Drury, M. Reeb","doi":"10.3389/fsoil.2022.1082940","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1082940","url":null,"abstract":"Summer-seeding legume cover crops can reduce erosion, mitigate nitrate leaching losses during the non-growing season, and provide bio-accumulated nitrogen (N) to the following crop. Very little information is available, however, on the most effective methods for terminating summer-seeded cover crops, or on the amount of N they can provide to subsequent crops. We therefore evaluated the impacts of selected legume cover crops and cover crop termination-tillage methods on corn (Zea mays L.) N credit and grain yield in a soybean (Glycine max Merr.) - winter wheat (Triticum aestivum L.)/cover crop - corn rotation over 3 consecutive years on a clay loam soil in southwestern Ontario. The cover crops were summer-seeded after wheat harvest, and included hairy vetch (Vicia villosa L. Roth), red clover (Trifolium pratense L.), white clover plus crimson clover mix (incarnatum and Trifolium alba L.), and a no cover crop control (CK). The cover crops were nested within termination-tillage method, including moldboard plow-down in fall, and herbicide spray-down in spring under strip-tillage or no-tillage then corn planting. Nitrogen fertilizer to corn was applied via side-dress at 200 kg N ha-1 to the CKs, and at 100 kg N ha-1 to the cover crops. Averaged over 3 years, above-ground biomass N level followed the pattern: hairy vetch > white clover plus crimson clover mix > red clover for fall plow-down termination. There were no significant differences in cover crop biomass N levels for spring termination. Corn response to cover crop was significantly affected by termination-tillage method and cover crop species, with poor corn stands after no-tillage, red clover and white plus crimson clover. Fall plow-down termination provided a range in N credit of 80-85 kg N ha-1, which was significantly greater than the N credit under herbicide spray-down in spring. Under spring strip-tillage and no-tillage, hairy vetch produced significantly greater corn grain yields than red clover and white plus crimson clover mix.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43886136","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 : 2022-12-23DOI: 10.3389/fsoil.2022.1096735
Lihong Tong, Jie Li, Ling Zhu, Shuo Zhang, Hu Zhou, Yizhong Lv, K. Zhu
Organic cultivation has been considered as an important cultivation approach for sustainable agriculture in the world. Whether organic cultivation can mitigate the negative impact of agriculture on the environment especially in greenhouses is still unclear. The purpose of this study is to investigate the long-term impacts in soil fertility and environment quality through organic cultivation (OC), low-input cultivation (LC) and conventional cultivation (CC) in greenhouses after 15 years of cultivation. We found that the soil organic carbon (SOC) content in the OC treatment was 1.7 times of that in CC, 1.2 times of that in the LC treatments. Vegetable yield and the content of alkali nitrogen, available phosphorus and available potassium in the OC treatment was significantly higher than those in the LC and CC treatments. Due to the high input of organic fertilizers, increased content of heavy metals (Cu, Zn, Pb, Cd, Cr and As) were observed in the OC treatment. In addition, organic cultivation resulted in considerable residue accumulation of tetracycline antibiotics (TCs) and pesticides in the soil. Ecological risk assessment of soil pollutants showed that organic cultivation has the highest ecological risk index. At present, organic partial substitution or low-input cultivation could be a promising approach for the development of sustainable agriculture. Graphical Abstract
{"title":"Effects of organic cultivation on soil fertility and soil environment quality in greenhouses","authors":"Lihong Tong, Jie Li, Ling Zhu, Shuo Zhang, Hu Zhou, Yizhong Lv, K. Zhu","doi":"10.3389/fsoil.2022.1096735","DOIUrl":"https://doi.org/10.3389/fsoil.2022.1096735","url":null,"abstract":"Organic cultivation has been considered as an important cultivation approach for sustainable agriculture in the world. Whether organic cultivation can mitigate the negative impact of agriculture on the environment especially in greenhouses is still unclear. The purpose of this study is to investigate the long-term impacts in soil fertility and environment quality through organic cultivation (OC), low-input cultivation (LC) and conventional cultivation (CC) in greenhouses after 15 years of cultivation. We found that the soil organic carbon (SOC) content in the OC treatment was 1.7 times of that in CC, 1.2 times of that in the LC treatments. Vegetable yield and the content of alkali nitrogen, available phosphorus and available potassium in the OC treatment was significantly higher than those in the LC and CC treatments. Due to the high input of organic fertilizers, increased content of heavy metals (Cu, Zn, Pb, Cd, Cr and As) were observed in the OC treatment. In addition, organic cultivation resulted in considerable residue accumulation of tetracycline antibiotics (TCs) and pesticides in the soil. Ecological risk assessment of soil pollutants showed that organic cultivation has the highest ecological risk index. At present, organic partial substitution or low-input cultivation could be a promising approach for the development of sustainable agriculture. Graphical Abstract","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48230057","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 : 2022-12-19DOI: 10.3389/fsoil.2022.949439
Stephen K. Formel, Allyson M. Martin, J. Pardue, Vijai Elango, K. Johnson, C. Gunsch, Emilie Lefèvre, Paige M. Varner, Yeon Ji Kim, B. Bernik, S. V. Van Bael
Recent work has suggested that the phytoremediation potential of S. alterniflora may be linked to a selection by the plant for oil-degrading microbial communities in the soil, in combination with enhanced delivery of oxygen and plant enzymes to the soil. In salt marshes, where the soil is saline and hypoxic, this relationship may be enhanced as plants in extreme environments have been found to be especially dependent on their microbiome for resilience to stress and to respond to toxins in the soil. Optimizing methods for restoration of oiled salt marshes would be especially meaningful in the Gulf of Mexico, where there is a persistently high threat of petroleum contamination. One favorable strategy for restoration of oiled sites might include planting S. alterniflora with a microbiome that has been pre-selected for an oiled environment. We examined this strategy with a two-year greenhouse experiment and found that planting S. alterniflora in an oiled environment enhances decomposition of oil residues without a clear negative impact on plant growth. Manipulation of the S. alterniflora microbiome through soil inoculation and through exposure to oil residues, elicited a detectable response of soil prokaryote communities to the presence of oil, while only demonstrating an analogous response in fungal communities in the plant roots and leaves. Yet, manipulation of the plant microbiome did not change plant morphology or relative decomposition of polycyclic aromatic hydrocarbons (PAHs) in the soil. Therefore, despite evident relationships between the plant, microbes, and oil, manipulation of the microbiome may not be a worthwhile addition to S. alterniflora phytoremediation strategies. Nevertheless, our work adds support for replanting S. alterniflora in oiled salt marshes as an effective strategy for reducing oil residues in salt marshes, in addition to the re-vegetation and erosion reduction benefits demonstrated by others.
{"title":"Decay of oil residues in the soil is enhanced by the presence of Spartina alterniflora, with no additional effect from microbiome manipulation","authors":"Stephen K. Formel, Allyson M. Martin, J. Pardue, Vijai Elango, K. Johnson, C. Gunsch, Emilie Lefèvre, Paige M. Varner, Yeon Ji Kim, B. Bernik, S. V. Van Bael","doi":"10.3389/fsoil.2022.949439","DOIUrl":"https://doi.org/10.3389/fsoil.2022.949439","url":null,"abstract":"Recent work has suggested that the phytoremediation potential of S. alterniflora may be linked to a selection by the plant for oil-degrading microbial communities in the soil, in combination with enhanced delivery of oxygen and plant enzymes to the soil. In salt marshes, where the soil is saline and hypoxic, this relationship may be enhanced as plants in extreme environments have been found to be especially dependent on their microbiome for resilience to stress and to respond to toxins in the soil. Optimizing methods for restoration of oiled salt marshes would be especially meaningful in the Gulf of Mexico, where there is a persistently high threat of petroleum contamination. One favorable strategy for restoration of oiled sites might include planting S. alterniflora with a microbiome that has been pre-selected for an oiled environment. We examined this strategy with a two-year greenhouse experiment and found that planting S. alterniflora in an oiled environment enhances decomposition of oil residues without a clear negative impact on plant growth. Manipulation of the S. alterniflora microbiome through soil inoculation and through exposure to oil residues, elicited a detectable response of soil prokaryote communities to the presence of oil, while only demonstrating an analogous response in fungal communities in the plant roots and leaves. Yet, manipulation of the plant microbiome did not change plant morphology or relative decomposition of polycyclic aromatic hydrocarbons (PAHs) in the soil. Therefore, despite evident relationships between the plant, microbes, and oil, manipulation of the microbiome may not be a worthwhile addition to S. alterniflora phytoremediation strategies. Nevertheless, our work adds support for replanting S. alterniflora in oiled salt marshes as an effective strategy for reducing oil residues in salt marshes, in addition to the re-vegetation and erosion reduction benefits demonstrated by others.","PeriodicalId":73107,"journal":{"name":"Frontiers in soil science","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91199348","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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