Abstract In an agroecosystem (AES), land-use types affect soil quality. As a result, determining soil quality in various land uses is critical. This study was carried out to evaluate the soil quality index (SQI) of the different land-use types in AESs of the Choke Mountain watershed, upper Blue Nile Basin. Forty-seven soil samples were taken from cultivated land (CL), grazing land (GL), plantation forest land (PFL), and natural forest land (NFL) of the five AESs. The minimum data set (MDS) was chosen using principal component analysis. To calculate SQI, five soil quality indicators were selected as an MDS: silt, pH, cation exchange capacity, exchangeable potassium, and soil organic matter. SQIs for the overall land uses were ordered as GL > NFL > PFL > CL. Compared with NFL, the SQIs of PFL and CL were reduced by 10% and 19.7%, respectively, whereas the SQI of GL was increased by 1.8%. Among AESs of Choke, SQI of GL was higher in the midland plain, dominated by Vertisol (AES 2), followed by the midland plain with Nitosols (AES 3). SQI of CL was intermediate, and SQIs of GL, NFL, and PFL were good. AES 2 of the watershed recorded the highest total SQI value, whereas hilly and mountainous highlands (AES 5) recorded the lowest SQIs compared to other AESs. Thus, site-specific land use and management practices across the various AESs should be recommended to policymakers and farmers for a sustainable ecosystem and environment.
{"title":"Soil quality index under different land-use types: the case of Choke Mountain agroecosystems, upper Blue Nile Basin, Ethiopia","authors":"D. Mesfin, E. Assefa, B. Simane","doi":"10.1139/cjss-2022-0053","DOIUrl":"https://doi.org/10.1139/cjss-2022-0053","url":null,"abstract":"Abstract In an agroecosystem (AES), land-use types affect soil quality. As a result, determining soil quality in various land uses is critical. This study was carried out to evaluate the soil quality index (SQI) of the different land-use types in AESs of the Choke Mountain watershed, upper Blue Nile Basin. Forty-seven soil samples were taken from cultivated land (CL), grazing land (GL), plantation forest land (PFL), and natural forest land (NFL) of the five AESs. The minimum data set (MDS) was chosen using principal component analysis. To calculate SQI, five soil quality indicators were selected as an MDS: silt, pH, cation exchange capacity, exchangeable potassium, and soil organic matter. SQIs for the overall land uses were ordered as GL > NFL > PFL > CL. Compared with NFL, the SQIs of PFL and CL were reduced by 10% and 19.7%, respectively, whereas the SQI of GL was increased by 1.8%. Among AESs of Choke, SQI of GL was higher in the midland plain, dominated by Vertisol (AES 2), followed by the midland plain with Nitosols (AES 3). SQI of CL was intermediate, and SQIs of GL, NFL, and PFL were good. AES 2 of the watershed recorded the highest total SQI value, whereas hilly and mountainous highlands (AES 5) recorded the lowest SQIs compared to other AESs. Thus, site-specific land use and management practices across the various AESs should be recommended to policymakers and farmers for a sustainable ecosystem and environment.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43290080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Saha, RaymondH. Thomas, K. Hawboldt, M. Nadeem, M. Cheema, L. Galagedara
Abstract The study aimed to investigate the effects of biochar (BC) application on hydraulic properties and nitrogen (N) transport in a podzolic soil profile. Soil samples were collected from an agricultural research field in Pasadena, Newfoundland, Canada. The following three types of leaching columns were prepared: (i) topsoil, (ii) top and E-horizon soil, and (iii) mixed soil (2:1 ratio of topsoil and E-horizon soil). Granular biochar (GBC) and powder biochar (PBC) were mixed with soils at the rate of 0%, 1% and 2% (w/w). BC’s morphological structure and pore size distribution were examined using a scanning electron microscope, and the specific surface area was assessed by the Brunauer−Emmett−Teller method. Soil physical and hydraulic properties (bulk density, porosity, field capacity (FC), permanent wilting point, plant available water (PAW)), leaching concentration of nitrate (NO3−) and ammonium (NH4+), and volume of leachate were measured through a total of 378 experiments under laboratory conditions. GBC and PBC showed hydrophobic and hydrophilic characteristics, respectively. With the 2% PBC amendment, porosity increased by 3%, FC by 10%, and PAW by 13% in the mixed soil and reduced NO3− leaching by 36% in top and E-horizon soil and NH4+ leaching by 72% in mixed soil. On the other hand, NO3− and NH4+ leaching was reduced by 26% and 33% in mixed soil when treated with 2% GBC. A 2% application rate for both BC (GBC and PBC) showed the best performance to enhance soil hydraulic properties and retain significant amounts of NO3− and NH4+ in the boreal podzol.
{"title":"Biochar applications to boreal podzol improve soil hydraulic properties and control nitrogen dynamics","authors":"R. Saha, RaymondH. Thomas, K. Hawboldt, M. Nadeem, M. Cheema, L. Galagedara","doi":"10.1139/cjss-2022-0086","DOIUrl":"https://doi.org/10.1139/cjss-2022-0086","url":null,"abstract":"Abstract The study aimed to investigate the effects of biochar (BC) application on hydraulic properties and nitrogen (N) transport in a podzolic soil profile. Soil samples were collected from an agricultural research field in Pasadena, Newfoundland, Canada. The following three types of leaching columns were prepared: (i) topsoil, (ii) top and E-horizon soil, and (iii) mixed soil (2:1 ratio of topsoil and E-horizon soil). Granular biochar (GBC) and powder biochar (PBC) were mixed with soils at the rate of 0%, 1% and 2% (w/w). BC’s morphological structure and pore size distribution were examined using a scanning electron microscope, and the specific surface area was assessed by the Brunauer−Emmett−Teller method. Soil physical and hydraulic properties (bulk density, porosity, field capacity (FC), permanent wilting point, plant available water (PAW)), leaching concentration of nitrate (NO3−) and ammonium (NH4+), and volume of leachate were measured through a total of 378 experiments under laboratory conditions. GBC and PBC showed hydrophobic and hydrophilic characteristics, respectively. With the 2% PBC amendment, porosity increased by 3%, FC by 10%, and PAW by 13% in the mixed soil and reduced NO3− leaching by 36% in top and E-horizon soil and NH4+ leaching by 72% in mixed soil. On the other hand, NO3− and NH4+ leaching was reduced by 26% and 33% in mixed soil when treated with 2% GBC. A 2% application rate for both BC (GBC and PBC) showed the best performance to enhance soil hydraulic properties and retain significant amounts of NO3− and NH4+ in the boreal podzol.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42449192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Mottling and gleying remain important characteristics for the classification of soils in Canada. The development of criteria for the morphological description of these redoximorphic soil features, for soil horizon nomenclature, for the taxonomy of gleysolic and gleyed soils, as well as for soil drainage classification, began in the mid-1940s and continued for the next four decades. Despite advancements elsewhere, notably with Soil Taxonomy and the World Reference Base, there have been minimal refinements made in Canada, during the past quarter century. Various issues are identified, including the need for more succinct and clearer definitions, a revision of standards for the field characterization of redoximorphic features, as well as more consistency in the application of concepts across existing taxa and systems. A taxonomic framework to more effectively reflect redoximorphic features, such as a new “Redoximorphic Phase” is also discussed. Ultimately, it is recommended that a special committee to be established to conduct a thorough study and present recommendations.
{"title":"Rationalizing mottling and gleying in the characterization and classification of Canadian soils","authors":"R. Heck, D. Saurette, C. J. Warren","doi":"10.1139/cjss-2022-0036","DOIUrl":"https://doi.org/10.1139/cjss-2022-0036","url":null,"abstract":"Abstract Mottling and gleying remain important characteristics for the classification of soils in Canada. The development of criteria for the morphological description of these redoximorphic soil features, for soil horizon nomenclature, for the taxonomy of gleysolic and gleyed soils, as well as for soil drainage classification, began in the mid-1940s and continued for the next four decades. Despite advancements elsewhere, notably with Soil Taxonomy and the World Reference Base, there have been minimal refinements made in Canada, during the past quarter century. Various issues are identified, including the need for more succinct and clearer definitions, a revision of standards for the field characterization of redoximorphic features, as well as more consistency in the application of concepts across existing taxa and systems. A taxonomic framework to more effectively reflect redoximorphic features, such as a new “Redoximorphic Phase” is also discussed. Ultimately, it is recommended that a special committee to be established to conduct a thorough study and present recommendations.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49504355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Pelster, A. Thiagarajan, C. Liang, M. Chantigny, C. Wagner-Riddle, K. Congreves, R. Lemke, A. Glenn, M. Tenuta, G. Hernandez‐Ramirez, S. Bittman, D. Hunt, J. Owens, D. MacDonald
Abstract National inventory reporting of agricultural nitrous oxide (N2O) emissions in Canada is based primarily on measurements obtained using static chambers. In regions with cold winters and an accumulated snowpack (including Canada), these measurements tend to focus on the growing season (typically May–October). However, research has shown that emissions continue throughout the non-growing season (NGS) and that these account for a significant proportion of annual emissions. In the Canadian National Inventory NGS emissions currently are assumed to be adequately captured in western Canada, while they are accounted for in eastern Canada by multiplying the growing season emissions by a correction factor of 1.4, a value that was derived based on a limited number of measurements. Here we use recent Canadian studies to validate this correction factor. We collected data from available Canadian studies that measured soil N2O emissions from agricultural systems for the entire year and determined the proportion of these emissions that occurred during the NGS. The proportion of annual N2O emissions that occurred during the NGS varied widely, ranging from −4% to 119% with a mean of 35.5%, compared to the previous estimate of 30%. Due to high variability, few differences were observed between means associated with climatic, soil, and management variables. To correct for NGS N2O emissions from Canadian agricultural soils, we suggest that the current correction factor for converting growing season to total annual emissions be changed from 1.4 to 1.55 and that this be used for all agricultural soils in Canada rather than just eastern Canada.
{"title":"Ratio of non-growing season to growing season N2O emissions in Canadian croplands: an update to national inventory methodology","authors":"D. Pelster, A. Thiagarajan, C. Liang, M. Chantigny, C. Wagner-Riddle, K. Congreves, R. Lemke, A. Glenn, M. Tenuta, G. Hernandez‐Ramirez, S. Bittman, D. Hunt, J. Owens, D. MacDonald","doi":"10.1139/cjss-2022-0101","DOIUrl":"https://doi.org/10.1139/cjss-2022-0101","url":null,"abstract":"Abstract National inventory reporting of agricultural nitrous oxide (N2O) emissions in Canada is based primarily on measurements obtained using static chambers. In regions with cold winters and an accumulated snowpack (including Canada), these measurements tend to focus on the growing season (typically May–October). However, research has shown that emissions continue throughout the non-growing season (NGS) and that these account for a significant proportion of annual emissions. In the Canadian National Inventory NGS emissions currently are assumed to be adequately captured in western Canada, while they are accounted for in eastern Canada by multiplying the growing season emissions by a correction factor of 1.4, a value that was derived based on a limited number of measurements. Here we use recent Canadian studies to validate this correction factor. We collected data from available Canadian studies that measured soil N2O emissions from agricultural systems for the entire year and determined the proportion of these emissions that occurred during the NGS. The proportion of annual N2O emissions that occurred during the NGS varied widely, ranging from −4% to 119% with a mean of 35.5%, compared to the previous estimate of 30%. Due to high variability, few differences were observed between means associated with climatic, soil, and management variables. To correct for NGS N2O emissions from Canadian agricultural soils, we suggest that the current correction factor for converting growing season to total annual emissions be changed from 1.4 to 1.55 and that this be used for all agricultural soils in Canada rather than just eastern Canada.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46994961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Tile drainage is installed in agricultural fields to remove excess soil moisture to allow earlier planting of spring crops. Water moving from soil into tile drainage lines will potentially create a moist environment for earthworms. This study investigated how earthworms were distributed around tile lines, and how their abundance was affected by moisture in field crops on sandy and clayey soils. Earthworm abundance and soil moisture were similar above and between tile lines. Earthworm biomass was low in dry soils, peaked at 41 g moisture 100 g−1, and declined in wetter soils, which affects the earthworm activity in agricultural fields.
{"title":"Earthworm distribution around tile drainage in agricultural fields of southwest Quebec, Canada","authors":"H. Diop, Leanne Ejack, A. Elmi, J. Whalen","doi":"10.1139/cjss-2022-0059","DOIUrl":"https://doi.org/10.1139/cjss-2022-0059","url":null,"abstract":"Abstract Tile drainage is installed in agricultural fields to remove excess soil moisture to allow earlier planting of spring crops. Water moving from soil into tile drainage lines will potentially create a moist environment for earthworms. This study investigated how earthworms were distributed around tile lines, and how their abundance was affected by moisture in field crops on sandy and clayey soils. Earthworm abundance and soil moisture were similar above and between tile lines. Earthworm biomass was low in dry soils, peaked at 41 g moisture 100 g−1, and declined in wetter soils, which affects the earthworm activity in agricultural fields.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45702986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Forest vehicle operation causes different degrees of compaction damage to the soil, which is related to the pressure-bearing characteristics of the soil. However, scholars have not profoundly investigated the pressure-bearing factors of forest soil. In this paper, disturbed brown coniferous forest soil was collected layer by layer, dried, screened, and tested with indoor pressing-plate tests with different pressing-plate shapes and diameters (side lengths). A kind of pressure–subsidence (P–Z) curve of hard soil, which is different from those of farmland soil and homogeneous remolded soil, was obtained and drawn as the P–Z curve. The results show that in the process of pressure subsidence, the forest soil gradually changed from loose to compact. Furthermore, the change of pressure-bearing subsidence of layered soil from this forest region was characterized first by the rapid increase of soil subsidence with the increase of pressure. Then, the subsidence speed became slower with the increase of pressure; finally, subsidence speed was much less affected by the increase in pressure. According to the pressure-bearing subsidence curve of forest soil, a new subsidence model is put forward in this paper. The new model has a good prediction effect on the subsidence curve of forest soil. This paper aims to provide a theoretical basis for studying soil pressure-bearing characteristics and the development of vehicles in high-passing forest areas.
{"title":"Establishment and experiment of a pressure-bearing subsidence model of layered soil in forest region","authors":"Yuan Zhou, Shufa Sun, Jingkai Wang, Miao Yu, Haoyu Yin, Fei Yang, Hao Luo","doi":"10.1139/cjss-2022-0067","DOIUrl":"https://doi.org/10.1139/cjss-2022-0067","url":null,"abstract":"Abstract Forest vehicle operation causes different degrees of compaction damage to the soil, which is related to the pressure-bearing characteristics of the soil. However, scholars have not profoundly investigated the pressure-bearing factors of forest soil. In this paper, disturbed brown coniferous forest soil was collected layer by layer, dried, screened, and tested with indoor pressing-plate tests with different pressing-plate shapes and diameters (side lengths). A kind of pressure–subsidence (P–Z) curve of hard soil, which is different from those of farmland soil and homogeneous remolded soil, was obtained and drawn as the P–Z curve. The results show that in the process of pressure subsidence, the forest soil gradually changed from loose to compact. Furthermore, the change of pressure-bearing subsidence of layered soil from this forest region was characterized first by the rapid increase of soil subsidence with the increase of pressure. Then, the subsidence speed became slower with the increase of pressure; finally, subsidence speed was much less affected by the increase in pressure. According to the pressure-bearing subsidence curve of forest soil, a new subsidence model is put forward in this paper. The new model has a good prediction effect on the subsidence curve of forest soil. This paper aims to provide a theoretical basis for studying soil pressure-bearing characteristics and the development of vehicles in high-passing forest areas.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47017397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract For one of Canada’s most important regions of crop production—the prairies—it’s uncertain if cover crops can be successfully integrated into rotations; if so, will soil nitrogen (N) cycling be influenced to benefit main crops? To address these gaps, we compared a crop rotation with cover crops (CC) vs. without cover crops (LR) from 2018 to 2021 in Saskatoon, SK. The main crops were grown in sequence of wheat–canola–potato–pea; the cover crops included red clover, berseem clover/oat mix, fall rye, and a brassica cover. Yield and aboveground biomass were collected each year and analyzed to determine crop yield and N use efficiency (NUE). Soil N availability was monitored in various ways, that is, by assessing pre-plant soil nitrate, soil inorganic N (SIN) supply rate, and potentially mineralizable N (PMN). We found that the influence on soil N dynamics was restricted to the non-growing season where cover crops reduced SIN supply rate and nitrate content compared to the conventional practice without cover crops. Yet, rotations with vs. without cover crop did not differ in crop NUEs, yields, or in-season N dynamics. We found some evidence that diversifying rotations with cover crops may help the system to function more like perennial systems in terms of regulating N in the long run; but had limited impact during the three years studied. To ensure that cover crops are effective and functional on the prairies, innovative design approaches are needed to adapt cover crops to reach soil health goals under prairie conditions.
{"title":"Do cover crops on the Canadian prairies affect soil nitrogen cycling?","authors":"O. Otchere, Y. Lawley, K. Congreves","doi":"10.1139/cjss-2022-0079","DOIUrl":"https://doi.org/10.1139/cjss-2022-0079","url":null,"abstract":"Abstract For one of Canada’s most important regions of crop production—the prairies—it’s uncertain if cover crops can be successfully integrated into rotations; if so, will soil nitrogen (N) cycling be influenced to benefit main crops? To address these gaps, we compared a crop rotation with cover crops (CC) vs. without cover crops (LR) from 2018 to 2021 in Saskatoon, SK. The main crops were grown in sequence of wheat–canola–potato–pea; the cover crops included red clover, berseem clover/oat mix, fall rye, and a brassica cover. Yield and aboveground biomass were collected each year and analyzed to determine crop yield and N use efficiency (NUE). Soil N availability was monitored in various ways, that is, by assessing pre-plant soil nitrate, soil inorganic N (SIN) supply rate, and potentially mineralizable N (PMN). We found that the influence on soil N dynamics was restricted to the non-growing season where cover crops reduced SIN supply rate and nitrate content compared to the conventional practice without cover crops. Yet, rotations with vs. without cover crop did not differ in crop NUEs, yields, or in-season N dynamics. We found some evidence that diversifying rotations with cover crops may help the system to function more like perennial systems in terms of regulating N in the long run; but had limited impact during the three years studied. To ensure that cover crops are effective and functional on the prairies, innovative design approaches are needed to adapt cover crops to reach soil health goals under prairie conditions.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44254122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huan Tong, Meiling Man, C. Wagner-Riddle, K. Dunfield, B. Deen, M. Simpson
Abstract Crop rotational diversity is an important part of sustainable agricultural and soil management to improve crop yield and soil fertility including enhancing soil organic matter (SOM) stabilization. Because of the physical protection via interactions with soil minerals, SOM in mineral-associated fractions is believed to be longer-lived and more stable relative to SOM in particulate (light) fractions. However, it is still unclear how crop rotational diversity alters soil carbon distribution, composition and stabilization in soil physical fractions. To address this, we studied a 37 years’ agricultural site with different crop rotational diversity (from continuous corn or alfalfa up to four species (corn, soybean, winter wheat, and red clover)). Soil carbon analysis, targeted compound analysis and nuclear magnetic resonance spectroscopy methods were used to obtain the distribution and degradation of SOM components in light and mineral-associated (F53–2000 µm, F2–53 µm, and F<2 µm) fractions. Higher soil organic carbon (SOC) concentrations were observed in F<2 µm with relatively high diversified crop rotations (three and four types of crops) compared to monoculture or two crops in the rotations, which suggests that carbon storage is enhanced in mineral-stabilized pools. Higher concentrations of long-chain aliphatic compounds as well as increased accumulation and preservation of lignin-derived compounds in fine aggregates (<53 µm) were also observed with relatively high diversified crop rotations. Overall, the increased concentration and preservation of specific SOM compounds as well as increased SOC in finer mineral-associated fractions (<53 µm) suggests that crop rotational diversity may enhance the long-term stability of SOM in agroecosystems.
{"title":"Crop rotational diversity alters the composition of stabilized soil organic matter compounds in soil physical fractions","authors":"Huan Tong, Meiling Man, C. Wagner-Riddle, K. Dunfield, B. Deen, M. Simpson","doi":"10.1139/cjss-2022-0058","DOIUrl":"https://doi.org/10.1139/cjss-2022-0058","url":null,"abstract":"Abstract Crop rotational diversity is an important part of sustainable agricultural and soil management to improve crop yield and soil fertility including enhancing soil organic matter (SOM) stabilization. Because of the physical protection via interactions with soil minerals, SOM in mineral-associated fractions is believed to be longer-lived and more stable relative to SOM in particulate (light) fractions. However, it is still unclear how crop rotational diversity alters soil carbon distribution, composition and stabilization in soil physical fractions. To address this, we studied a 37 years’ agricultural site with different crop rotational diversity (from continuous corn or alfalfa up to four species (corn, soybean, winter wheat, and red clover)). Soil carbon analysis, targeted compound analysis and nuclear magnetic resonance spectroscopy methods were used to obtain the distribution and degradation of SOM components in light and mineral-associated (F53–2000 µm, F2–53 µm, and F<2 µm) fractions. Higher soil organic carbon (SOC) concentrations were observed in F<2 µm with relatively high diversified crop rotations (three and four types of crops) compared to monoculture or two crops in the rotations, which suggests that carbon storage is enhanced in mineral-stabilized pools. Higher concentrations of long-chain aliphatic compounds as well as increased accumulation and preservation of lignin-derived compounds in fine aggregates (<53 µm) were also observed with relatively high diversified crop rotations. Overall, the increased concentration and preservation of specific SOM compounds as well as increased SOC in finer mineral-associated fractions (<53 µm) suggests that crop rotational diversity may enhance the long-term stability of SOM in agroecosystems.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45760128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Wetland soil types, which can be distinguished based on calcium carbonate content, vary in their effect on ecosystem functions like phosphorus retention, salinity contributions, and greenhouse gas forcing. These soil types may be predictively mapped with machine learning models that use terrain derivatives calculated from high-resolution digital elevation models. Soil profiles from three Saskatchewan study sites were classified into three functional categories—upland, calcareous wetland, or noncalcareous wetland—and used to train random forest models for predictive soil mapping. Multiple terrain derivatives were included as predictor variables to capture local- and landscape-scale morphometry and hydrology influences, including five derivatives developed for this study. Models were developed at three spatial resolutions: 2, 5, and 10 m, and tested via internal cross-validation and independent validation with datasets from previous studies. Predictive accuracies were highest when mapping at 2 m resolution (independent validation accuracy range = 64%–100%) but also successful when mapping at 5 and 10 m resolutions (independent validation accuracy range = 63%–100%); however, visual inspection determined that the maps generated at 10 m resolution were less detailed and occasionally featured questionable discontinuous soil distributions. Three of the five terrain derivatives developed for this study were among the most important predictor variables (first, second, and 10th most important). Models trained using only data from a specific site had slightly better performance than models trained using data from all sites, except in regions where training data were lacking.
{"title":"Predictive mapping of wetland soil types in the Canadian Prairie Pothole Region using high-resolution digital elevation model terrain derivatives","authors":"J. Kiss, A. Bedard-Haughn, P. Sorenson","doi":"10.1139/cjss-2022-0034","DOIUrl":"https://doi.org/10.1139/cjss-2022-0034","url":null,"abstract":"Abstract Wetland soil types, which can be distinguished based on calcium carbonate content, vary in their effect on ecosystem functions like phosphorus retention, salinity contributions, and greenhouse gas forcing. These soil types may be predictively mapped with machine learning models that use terrain derivatives calculated from high-resolution digital elevation models. Soil profiles from three Saskatchewan study sites were classified into three functional categories—upland, calcareous wetland, or noncalcareous wetland—and used to train random forest models for predictive soil mapping. Multiple terrain derivatives were included as predictor variables to capture local- and landscape-scale morphometry and hydrology influences, including five derivatives developed for this study. Models were developed at three spatial resolutions: 2, 5, and 10 m, and tested via internal cross-validation and independent validation with datasets from previous studies. Predictive accuracies were highest when mapping at 2 m resolution (independent validation accuracy range = 64%–100%) but also successful when mapping at 5 and 10 m resolutions (independent validation accuracy range = 63%–100%); however, visual inspection determined that the maps generated at 10 m resolution were less detailed and occasionally featured questionable discontinuous soil distributions. Three of the five terrain derivatives developed for this study were among the most important predictor variables (first, second, and 10th most important). Models trained using only data from a specific site had slightly better performance than models trained using data from all sites, except in regions where training data were lacking.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64204739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Myra Nazeer, M. J. Khan, D. Muhammad, Ahmad Masood Khan
Abstract The waste of coal mining activities causes accumulation of hazardous elements in soil for plants. Biochar is considered an important soil remediation strategy to stabilize the heavy metals. The aim of this study was to quantify the effect of biochar sources and rate on the heavy metal stabilization in coal-contaminated soil. Biochars of three feedstocks (maize straw (MBC), rice straw (RBC), and sugarcane bagasse (SBC)) with four levels (0%, 0.5%, 1%, and 2%, i.e., 0, 10, 20, and 40 ton ha−1) were applied to two types of soils (naturally contaminated soil (NCS) versus artificially contaminated soil (ACS) spiked with Cd, Cu, Cr, and Pb). Plastic pots were incubated at 30% field capacity for 90 days at 25 °C, and soil pH, electrical conductivity (EC), and heavy metals concentration were measured after 1, 4, 8, and 12 weeks. Among the biochars, RBC showed maximum immobilization of Cd, Pb, Cu, and Cr as compared with MBC and SBC. Similarly, biochar application increased heavy immobilization, being maximum at 2% (40 ton ha−1) rate compared with control. The pH of both soils with biochar addition increased as compared with control. The remediation effect of biochar on heavy metal stabilization was positive over time. The higher rate (40 ton ha−1) of RBC for ACS and MBC for NCS could be used effectively for heavy metal stabilization.
摘要:煤矿开采废弃物对植物有害元素在土壤中积累。生物炭被认为是稳定重金属的重要土壤修复策略。本研究的目的是量化生物炭来源和速率对煤污染土壤重金属稳定化的影响。将玉米秸秆(MBC)、水稻秸秆(RBC)和甘蔗渣(SBC)三种原料(0%、0.5%、1%和2%，即0、10、20和40 ton ha - 1)的生物炭分别施用于两种土壤(自然污染土壤(NCS)和添加Cd、Cu、Cr和Pb的人工污染土壤(ACS))。在25℃条件下，以30%田间容量培养90 d，分别于1、4、8、12周后测定土壤pH、电导率(EC)和重金属浓度。在生物炭中，与MBC和SBC相比，RBC对Cd、Pb、Cu和Cr的固定化效果最好。同样，施用生物炭增加了重度固定化，与对照相比，最大固定化率为2%(40吨公顷- 1)。与对照相比，添加生物炭的土壤pH值均有所增加。随着时间的推移，生物炭对重金属稳定的修复效果是积极的。较高的速率(40吨ha - 1) RBC用于ACS和MBC用于NCS可以有效地用于重金属稳定。
{"title":"Biochar application stabilized the heavy metals in coal mined soil","authors":"Myra Nazeer, M. J. Khan, D. Muhammad, Ahmad Masood Khan","doi":"10.1139/cjss-2022-0073","DOIUrl":"https://doi.org/10.1139/cjss-2022-0073","url":null,"abstract":"Abstract The waste of coal mining activities causes accumulation of hazardous elements in soil for plants. Biochar is considered an important soil remediation strategy to stabilize the heavy metals. The aim of this study was to quantify the effect of biochar sources and rate on the heavy metal stabilization in coal-contaminated soil. Biochars of three feedstocks (maize straw (MBC), rice straw (RBC), and sugarcane bagasse (SBC)) with four levels (0%, 0.5%, 1%, and 2%, i.e., 0, 10, 20, and 40 ton ha−1) were applied to two types of soils (naturally contaminated soil (NCS) versus artificially contaminated soil (ACS) spiked with Cd, Cu, Cr, and Pb). Plastic pots were incubated at 30% field capacity for 90 days at 25 °C, and soil pH, electrical conductivity (EC), and heavy metals concentration were measured after 1, 4, 8, and 12 weeks. Among the biochars, RBC showed maximum immobilization of Cd, Pb, Cu, and Cr as compared with MBC and SBC. Similarly, biochar application increased heavy immobilization, being maximum at 2% (40 ton ha−1) rate compared with control. The pH of both soils with biochar addition increased as compared with control. The remediation effect of biochar on heavy metal stabilization was positive over time. The higher rate (40 ton ha−1) of RBC for ACS and MBC for NCS could be used effectively for heavy metal stabilization.","PeriodicalId":9384,"journal":{"name":"Canadian Journal of Soil Science","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42920802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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