Recent research has suggested that increased industrial and technological utilization of antimony and bismuth necessitates greater research to determine the soil and water chemistry and the environmental risks associa...Recent research has suggested that increased industrial and technological utilization of antimony and bismuth necessitates greater research to determine the soil and water chemistry and the environmental risks associated with these elements. The near-total soil profile concentrations of antimony and bismuth were determined for key soil series across southeastern Missouri. The antimony concentrations ranged from 0.65 to 0.08 mg kg<sup>−</sup><sup>1</sup>, whereas the bismuth soil profile concentrations ranged from 0.92 to 0.03 mg kg<sup>−</sup><sup>1</sup>. Most pedons showed antimony concentrations ranging from 20 to 30 mg kg<sup>−</sup><sup>1</sup>, whereas bismuth concentrations were commonly 10 to 20 mg kg<sup>−</sup><sup>1</sup>. For soils having argillic horizons, antimony and bismuth concentrations were greater for the illuvial horizons than the eluvial horizons, whereas Entisols, Inceptisols, and one Vertisol showed rather uniform antimony and bismuth concentrations, features paralleling the soil texture distribution. Both antimony and bismuth showed significant correlations with iron.展开更多
Constructed wetlands are engineered structures designed to simulate processes of natural wetlands to mitigate anthropogenic organic and inorganic materials to shelter soil and water resources. This review focuses on t...Constructed wetlands are engineered structures designed to simulate processes of natural wetlands to mitigate anthropogenic organic and inorganic materials to shelter soil and water resources. This review focuses on the global interest in constructed wetland application to sustain soil health and water quality and water abundance. Engineering criterion remains a function of nutrient chemistry and load with suitability factors including the local soil and hydrogeology constraints, climate, vegetation selection, the degree of required influent improvement, and reactor types and sizes. Future research needs to focus on: 1) reactor designs criteria, 2) the biology of the microbial community, 3) selection criteria for native vegetation, and 4) criteria to reapply treated water to foster land productivity, especially for region’s experiencing water deficiencies.展开更多
Climate change is manifesting across the USA Mid-South and is impacting agricultural productivity, including the production of rice. This manuscript is a review of pertinent global literature concerning the effect of ...Climate change is manifesting across the USA Mid-South and is impacting agricultural productivity, including the production of rice. This manuscript is a review of pertinent global literature concerning the effect of increasing temperature and carbon dioxide concentrations involving: 1) rice growth and development with an emphasis on spikelet sterility, 2) water availability for irrigation with the specter of aquifer overdraft and emerging water management technologies intended to improve water use efficiency, 3) the soil-plant continuum related to greenhouse gas emission and research avenues supporting agronomic practices that limit these emissions, and 4) region wide assessment of the economic and agronomic indicators to infer changes in the agricultural infrastructure and markets. Based on the global literature review and specific circumstances for USA Mid-South rice production, explicit proposals to mitigate and alleviate climate change are proposed. Key climate change mitigation proposals include: 1) support irrigation technologies that limit water usage and reduce methane emissions, 2) support soil carbon enhancement and newly emerging soil health agronomic practices, 3) achieve a greater usage of remote sensing activities to detect, in real time, field stresses, 4) support rice breeding activities that benefit furrow irrigation and provide heat tolerance, and 5) coordinate a rice region wide consensus to achieve farm gate activities that address climate change.展开更多
Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morpho...Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morphology. The protocol reveals that gross elemental soil profile distributions do provide evidence that certain pedogenic processes are operating within a group of soils. Concentration differences between instrumental neutron activation analysis and an aqua regia digestion protocol infer that alkali metals, alkaline earth metals, transition metals and the rare earth elements are only incompletely weathered from primary minerals. Transition metals, alkali metals, alkaline earths, metalloids, and the rare earth elements all show inter-horizon mobility. Lessivage and the mobility of elements presumably adsorbed on soluble or suspended organic materials are the dominant soil processes influencing the soil profile redistribution of elements and the majority of these elements are shown to correlate with the soil profile distribution of Fe. Base cycling by the forest vegetation was shown to support A horizon enrichment of Ca, Sr, Ba, P, S, Mn, Zn, Sn and Pb. For clinical practice, elemental analysis may reveal important soil profile elemental differences when applied to variation of one soil forming factors, such as a chronosequence or toposequence within a landscape or soil association. Advantages and limitations of the protocol in identifying pedogenic pathways are discussed.展开更多
The soil chemistry of gallium, indium, and thallium is not well defined, particularly with emerging evidence that these elements have toxic properties and may influence food safety. The purpose of this investigation w...The soil chemistry of gallium, indium, and thallium is not well defined, particularly with emerging evidence that these elements have toxic properties and may influence food safety. The purpose of this investigation was to estimate the soil concentrations of gallium, indium, and thallium and determine if these elements have a soil chemistry like aluminum and therefore demonstrate significant concentration correlations with aluminum. Twenty-seven soil series were selected, and the elemental concentrations were determined using aqua regia digestion with analytical determination performed using inductively coupled plasma emission-mass spectroscopy. The concentrations of gallium, indium, and thallium generally compared with the known literature. Aluminum-gallium and aluminum-thallium exhibited significant concentration correlations across the soil horizons of the sampled soils. Aluminum, gallium, and thallium did demonstrate concentration increases in soil horizons having illuviation of phyllosilicates, implying these phyllosilicates have adsorption and isomorphic substitution behaviors involving these elements.展开更多
Selenium is a trace element in animal nutrition provided through forage. Vegetation should accumulate adequate levels to meet this livestock requirement. This study assessed southeastern Missouri soils for their selen...Selenium is a trace element in animal nutrition provided through forage. Vegetation should accumulate adequate levels to meet this livestock requirement. This study assessed southeastern Missouri soils for their selenium concentrations. Multiple sites across southeastern Missouri were sampled, from which a total of twenty-six soils were collected. Parent materials ranged from coarse to fine-textured alluvium and terrace deposits, colluvium, loess, limestone residuum and rhyolite residuum from poor to well-drained soils. The mean whole soil selenium contents ranged from less than 0.1 mg Se kg<sup>-1</sup> for the Kaintuck pedons to 1.0, 2.2, and 2.4 mg Se kg<sup>-1</sup> for the Irondale, Killarney, and Frenchmill pedons. For individual soils, Menfro pedons were deep, well-drained soils developed in loess. Paired Menfro pedons having similar soil morphology and having A-E-BE-Bt-C horizon sequences were selected and the greatest selenium concentrations were in the argillic horizons. Soils having fine textures (clayey) had moderate selenium concentrations, whereas soils having coarse textures (sandy) revealed minimal selenium concentrations. A wide soil selenium concentration variation was shown;however, no toxic selenium levels were measured. Therefore, soil selenium toxicity is not a regional issue. Noting that soil selenium concentrations in medium to fine-textured soils are appropriate for providing selenium to livestock, the need to artificially soil incorporate selenium or add selenium into the livestock ration remains critical for coarse-textured soils.展开更多
The presence of increasing quantities of greenhouse gases is fostering climate change. This review chronicles the emerging research addressing the role of soil to sequester carbon across biomes, understand the soil me...The presence of increasing quantities of greenhouse gases is fostering climate change. This review chronicles the emerging research addressing the role of soil to sequester carbon across biomes, understand the soil mechanisms responsible for soil carbon preservation and indicate the need to estimate the intensity for site-specific carbon sequestration. To negate the continuing increase of atmospheric greenhouse gases requires using well-documented soil pathways to sequester carbon. For deciduous forests, emerging concepts center around two approaches: 1) increasing the ecosystem’s net primary productivity coupled with increasing the carbon supply into soil using appropriate land management practices, and 2) supporting soil processes that increase soil carbon retention. New perspectives suggest that soil carbon may be preferentially preserved because organic materials are adsorbed onto phyllosilicates and oxyhydroxides and subsequently protected from microbial degradation because of soil structure improvement. Thus, augmenting soil structure may promote soil organic matter persistence. Each soil has a soil carbon carrying capacity;however, soil survey databases infer that soil organic matter concentrations have a significant variance at the soil series level. The need exists for more precise estimates of the soil’s carbon carrying capacity at the pedon level to support land management practices that encourage land management options designed to preserve soil carbon. However, the complexity of the soil system may limit its usefulness for routine soil management decisions. Our modern understanding of soil carbon preservation processes and emerging soil carbon saturation deficit concepts may potentially improve decision support tools for managing soils for carbon sequestration.展开更多
Alfisols in USA taxonomy are “deciduous forest” soils having an argillic horizon with a base saturation in the control section greater than 35%. Alfisols are geographically extensive and support productive agricultu...Alfisols in USA taxonomy are “deciduous forest” soils having an argillic horizon with a base saturation in the control section greater than 35%. Alfisols are geographically extensive and support productive agriculture and deciduous forest ecosystems. Understanding Alfisol genesis, including the presence and intensity of the dominant soil processes, facilitates best management practices that provide stewardship for these soil resources and improves forest and agriculture productivity. Four Alfisols, presently having mature forest settings and located in the central United States along the Mississippi River, were selected for soil and landscape description, classification, and delineation of the dominant soil forming processes. Excavated soils were described and routinely sampled for subsequent physical, chemical, and mineralogical analysis. An aqua regia digestion protocol provided elemental analysis for identifying and inferring the intensity of soil forming processes. The dominant soil forming factors include 1) organic matter accumulation, 2) clay eluviation-illuviation, 3) acidification, 4) base cation accumulation in the A horizons by the forest vegetation, 5) Fe-oxyhydroxide formation, and 6) clay mineral synthesis. Two soils were developed entirely in Peoria loess and two soils were developed in Peoria Loess overlying Ordovician limestone residuum. Ecological site descriptions provide land managers information for evaluating land suitability and the capability to implement different management activities without ecosystem disturbance. Best management practices for the described landforms and based on their Ecological Site Descriptions are presented.展开更多
Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties f...Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties for agriculture, forestry, or wild-life habitat. The typical practice of gypsum application is problematic given inability to provide drainage. Natraqualfs located in southeastern Missouri present an acid argillic horizon superimposed on a natric horizon, where the exchangeable sodium percentage and an alkaline reaction are characteristic attributes. Ferrolysis is an active soil process that is slowly degrading the natric horizon because of exchangeable Al<sup>3+</sup> and H<sup>+</sup> generation and re-stabilization of the soil structure, permitting leaching of the sodium.展开更多
Nitrogen transport from agriculture production fields raises the specter of environmental degradation of freshwater resources. Our objectives were to document and evaluate nitrate-N, ammonium-N, phosphorus and other n...Nitrogen transport from agriculture production fields raises the specter of environmental degradation of freshwater resources. Our objectives were to document and evaluate nitrate-N, ammonium-N, phosphorus and other nutrients emanating from a 40-ha controlled subsurface irrigation drainage technology coupled in series with a denitrification bioreactor. The intent of the denitrification bioreactor is to create an environment for anoxic microbial populations to support denitrification. We monitored the tile-drainage effluent and denitrification bioreactor water chemistry under a corn-soybean rotation to estimate the nutrient concentrations and the competence of the denitrification bioreactor to foster denitrification. Nitrate-N bearing tile drainage effluents ranged from less than 1.5 to 109 mg NO3- -N/L, with the nitrate concentration differences attributed primarily to the: 1) timing of nitrogen fertilization for corn, 2) soil mineralization and residue decomposition, and 3) intense rainfall events. The denitrification bioreactor was highly effective in reducing drainage water nitrate-N concentrations providing the rate of water flow through the denitrification bioreactor permitted sufficient time for equilibrium to be attained for the nitrate reduction reactions. The nitrate-N concentrations entering the denitrification bioreactor ranged from 0.4 to 103 mg NO3-?-N/L in 2018, whereas the outlet nitrate concentrations typically ranged from 0.3 to 5.2 mg NO3- -N/L in 2018. Nitrate tile-drainage effluent concentrations in 2019 were marginal, given soybeans obtain nitrogen from biological nitrogen fixation. Nutrient uptake by corn reduced the soil nitrate leaching pool and created nitrogen-bearing biomass, features important for formulating best management practices.展开更多
Soil aluminum phytotoxicity has been a major research area since the inception of modern soil science. Acid soils, which typically manifest plant aluminum toxicity, are frequently dedicated to food production, thus yi...Soil aluminum phytotoxicity has been a major research area since the inception of modern soil science. Acid soils, which typically manifest plant aluminum toxicity, are frequently dedicated to food production, thus yield and quality reductions influence food security. This manuscript reviews our modern understanding of 1) soil aluminum hydrolysis and polymerization, 2) aluminum complexation with inorganic and organic anions, 3) aluminum interference with vital plant physiological processes, 4) aluminum and forest ecosystem productivity, and 5) demonstrates the software simulation of aluminum reactivity and its role in predicting soil behavior. The manuscript also provides a perspective for future soil-aluminum research critical to maintaining food security and food quality.展开更多
Many Missouri forest soils exhibit fragipans, which influence soil productivity, ecosystem services and land management. Fragipan bearing soils tend to occur where loess thickness is moderate (1 to 2 meters) or where ...Many Missouri forest soils exhibit fragipans, which influence soil productivity, ecosystem services and land management. Fragipan bearing soils tend to occur where loess thickness is moderate (1 to 2 meters) or where the soil profile exhibits evidence of mass wasting of weathered limestone residuum. Consensus is consolidating around the self-weight collapse of loess and residuum after repeated wetting and desiccation. The use of gravel as an indicator of parent material differences and its correlation with fragipan development is not perfectly aligned, thus although most fragipans do exhibit a bisequal soil profile, the placement of the lithologic discontinuity is difficult given mass wasting, eluviation-illuviation, side slopes, and other soil processes that contribute to increasing the bulk density and conferring strength. Fragipan genesis is evolving;however, research involving Ecosystem Site Descriptions are a fusion of a land parcel’s soil properties, vegetational community, hydrology, and climate to guide land management. Ecological Site Descriptions associated with fragipan bearing soils are necessary, especially when making land management decisions.展开更多
Arsenic contamination of water,soil and food is a global concern.Rice(Oryza sativa)is uniquely involved because rice is a major staple food and its culture in anaerobic soil promotes arsenic accumulation.This manuscri...Arsenic contamination of water,soil and food is a global concern.Rice(Oryza sativa)is uniquely involved because rice is a major staple food and its culture in anaerobic soil promotes arsenic accumulation.This manuscript attempts to apprise our current understanding of arsenic in rice in terms of:(i)the severity of the arsenic problem,(ii)the various irrigation technologies being advanced to mitigate arsenic rice accumulation,and(iii)the potential for emerging water conserving irrigation systems to reduce aquifer overdraft.The leading contenders to mitigate arsenic accumulation include(i)plant breeding,(ii)irrigation technologies,(iii)soil amendments that restrict arsenic bioavailability,and(iv)groundwater purification.Recent research involving(i)wetting and drying irrigation and(ii)furrow irrigation typically conserve water and inhibit arsenic accumulation.In Missouri,furrow irrigation generally reduced rice seed arsenic concentrations to less than 0.05 mg∙kg−1.Plant breeding to both limit arsenic accumulation and tolerate increased temperatures show promise,yet detailed research needs to be expanded.展开更多
The Mississippi River watershed encompasses a substantial portion of the central United States,receiving effluent from soil runoff,urban and industrial centers.In Missouri,two soil series,with two pedons per series,lo...The Mississippi River watershed encompasses a substantial portion of the central United States,receiving effluent from soil runoff,urban and industrial centers.In Missouri,two soil series,with two pedons per series,located on the Mississippi River annual floodplain were morphologically described,classified,and chemically characterized.Aqua regia digestion and sodium acetate extractions were performed to assess the concentrations of 20 elements.A special emphasis was devoted to lead,cadmium,and zinc as these elements are commonly associated with heavy metal pollution.Cadmium was the only element showing an elevated concentration on one of the soil series.The pollution index and enrichment factor values suggested“cadmium impacted soils”.The elements used for geochemical background concentrations were determined using adjacent floodplain soils not experiencing annual Mississippi River flooding.However,geochemical background concentrations for cadmium were smaller than the sampled Mississippi River floodplain soils.Thus,the pollution index and the enrichment factor may have indicated“cadmium impacted soils”;however,the main difference is the soils used for the geochemical background soils and the Mississippi River floodplain soils simply exhibited slightly different cadmium concentrations.We conclude that cadmium may be accumulating in these annual flood prone soils;however,the intensity of the current cadmium accumulations is not appreciably above values that would warrant immediate remediation.展开更多
文摘Recent research has suggested that increased industrial and technological utilization of antimony and bismuth necessitates greater research to determine the soil and water chemistry and the environmental risks associated with these elements. The near-total soil profile concentrations of antimony and bismuth were determined for key soil series across southeastern Missouri. The antimony concentrations ranged from 0.65 to 0.08 mg kg<sup>−</sup><sup>1</sup>, whereas the bismuth soil profile concentrations ranged from 0.92 to 0.03 mg kg<sup>−</sup><sup>1</sup>. Most pedons showed antimony concentrations ranging from 20 to 30 mg kg<sup>−</sup><sup>1</sup>, whereas bismuth concentrations were commonly 10 to 20 mg kg<sup>−</sup><sup>1</sup>. For soils having argillic horizons, antimony and bismuth concentrations were greater for the illuvial horizons than the eluvial horizons, whereas Entisols, Inceptisols, and one Vertisol showed rather uniform antimony and bismuth concentrations, features paralleling the soil texture distribution. Both antimony and bismuth showed significant correlations with iron.
文摘Constructed wetlands are engineered structures designed to simulate processes of natural wetlands to mitigate anthropogenic organic and inorganic materials to shelter soil and water resources. This review focuses on the global interest in constructed wetland application to sustain soil health and water quality and water abundance. Engineering criterion remains a function of nutrient chemistry and load with suitability factors including the local soil and hydrogeology constraints, climate, vegetation selection, the degree of required influent improvement, and reactor types and sizes. Future research needs to focus on: 1) reactor designs criteria, 2) the biology of the microbial community, 3) selection criteria for native vegetation, and 4) criteria to reapply treated water to foster land productivity, especially for region’s experiencing water deficiencies.
文摘Climate change is manifesting across the USA Mid-South and is impacting agricultural productivity, including the production of rice. This manuscript is a review of pertinent global literature concerning the effect of increasing temperature and carbon dioxide concentrations involving: 1) rice growth and development with an emphasis on spikelet sterility, 2) water availability for irrigation with the specter of aquifer overdraft and emerging water management technologies intended to improve water use efficiency, 3) the soil-plant continuum related to greenhouse gas emission and research avenues supporting agronomic practices that limit these emissions, and 4) region wide assessment of the economic and agronomic indicators to infer changes in the agricultural infrastructure and markets. Based on the global literature review and specific circumstances for USA Mid-South rice production, explicit proposals to mitigate and alleviate climate change are proposed. Key climate change mitigation proposals include: 1) support irrigation technologies that limit water usage and reduce methane emissions, 2) support soil carbon enhancement and newly emerging soil health agronomic practices, 3) achieve a greater usage of remote sensing activities to detect, in real time, field stresses, 4) support rice breeding activities that benefit furrow irrigation and provide heat tolerance, and 5) coordinate a rice region wide consensus to achieve farm gate activities that address climate change.
文摘Bisequal soils in northern Wisconsin were described and characterized with the intent to determine if a near total elemental analysis protocol may estimate the effect of selected soil pedogenic pathways on soil morphology. The protocol reveals that gross elemental soil profile distributions do provide evidence that certain pedogenic processes are operating within a group of soils. Concentration differences between instrumental neutron activation analysis and an aqua regia digestion protocol infer that alkali metals, alkaline earth metals, transition metals and the rare earth elements are only incompletely weathered from primary minerals. Transition metals, alkali metals, alkaline earths, metalloids, and the rare earth elements all show inter-horizon mobility. Lessivage and the mobility of elements presumably adsorbed on soluble or suspended organic materials are the dominant soil processes influencing the soil profile redistribution of elements and the majority of these elements are shown to correlate with the soil profile distribution of Fe. Base cycling by the forest vegetation was shown to support A horizon enrichment of Ca, Sr, Ba, P, S, Mn, Zn, Sn and Pb. For clinical practice, elemental analysis may reveal important soil profile elemental differences when applied to variation of one soil forming factors, such as a chronosequence or toposequence within a landscape or soil association. Advantages and limitations of the protocol in identifying pedogenic pathways are discussed.
文摘The soil chemistry of gallium, indium, and thallium is not well defined, particularly with emerging evidence that these elements have toxic properties and may influence food safety. The purpose of this investigation was to estimate the soil concentrations of gallium, indium, and thallium and determine if these elements have a soil chemistry like aluminum and therefore demonstrate significant concentration correlations with aluminum. Twenty-seven soil series were selected, and the elemental concentrations were determined using aqua regia digestion with analytical determination performed using inductively coupled plasma emission-mass spectroscopy. The concentrations of gallium, indium, and thallium generally compared with the known literature. Aluminum-gallium and aluminum-thallium exhibited significant concentration correlations across the soil horizons of the sampled soils. Aluminum, gallium, and thallium did demonstrate concentration increases in soil horizons having illuviation of phyllosilicates, implying these phyllosilicates have adsorption and isomorphic substitution behaviors involving these elements.
文摘Selenium is a trace element in animal nutrition provided through forage. Vegetation should accumulate adequate levels to meet this livestock requirement. This study assessed southeastern Missouri soils for their selenium concentrations. Multiple sites across southeastern Missouri were sampled, from which a total of twenty-six soils were collected. Parent materials ranged from coarse to fine-textured alluvium and terrace deposits, colluvium, loess, limestone residuum and rhyolite residuum from poor to well-drained soils. The mean whole soil selenium contents ranged from less than 0.1 mg Se kg<sup>-1</sup> for the Kaintuck pedons to 1.0, 2.2, and 2.4 mg Se kg<sup>-1</sup> for the Irondale, Killarney, and Frenchmill pedons. For individual soils, Menfro pedons were deep, well-drained soils developed in loess. Paired Menfro pedons having similar soil morphology and having A-E-BE-Bt-C horizon sequences were selected and the greatest selenium concentrations were in the argillic horizons. Soils having fine textures (clayey) had moderate selenium concentrations, whereas soils having coarse textures (sandy) revealed minimal selenium concentrations. A wide soil selenium concentration variation was shown;however, no toxic selenium levels were measured. Therefore, soil selenium toxicity is not a regional issue. Noting that soil selenium concentrations in medium to fine-textured soils are appropriate for providing selenium to livestock, the need to artificially soil incorporate selenium or add selenium into the livestock ration remains critical for coarse-textured soils.
文摘The presence of increasing quantities of greenhouse gases is fostering climate change. This review chronicles the emerging research addressing the role of soil to sequester carbon across biomes, understand the soil mechanisms responsible for soil carbon preservation and indicate the need to estimate the intensity for site-specific carbon sequestration. To negate the continuing increase of atmospheric greenhouse gases requires using well-documented soil pathways to sequester carbon. For deciduous forests, emerging concepts center around two approaches: 1) increasing the ecosystem’s net primary productivity coupled with increasing the carbon supply into soil using appropriate land management practices, and 2) supporting soil processes that increase soil carbon retention. New perspectives suggest that soil carbon may be preferentially preserved because organic materials are adsorbed onto phyllosilicates and oxyhydroxides and subsequently protected from microbial degradation because of soil structure improvement. Thus, augmenting soil structure may promote soil organic matter persistence. Each soil has a soil carbon carrying capacity;however, soil survey databases infer that soil organic matter concentrations have a significant variance at the soil series level. The need exists for more precise estimates of the soil’s carbon carrying capacity at the pedon level to support land management practices that encourage land management options designed to preserve soil carbon. However, the complexity of the soil system may limit its usefulness for routine soil management decisions. Our modern understanding of soil carbon preservation processes and emerging soil carbon saturation deficit concepts may potentially improve decision support tools for managing soils for carbon sequestration.
文摘Alfisols in USA taxonomy are “deciduous forest” soils having an argillic horizon with a base saturation in the control section greater than 35%. Alfisols are geographically extensive and support productive agriculture and deciduous forest ecosystems. Understanding Alfisol genesis, including the presence and intensity of the dominant soil processes, facilitates best management practices that provide stewardship for these soil resources and improves forest and agriculture productivity. Four Alfisols, presently having mature forest settings and located in the central United States along the Mississippi River, were selected for soil and landscape description, classification, and delineation of the dominant soil forming processes. Excavated soils were described and routinely sampled for subsequent physical, chemical, and mineralogical analysis. An aqua regia digestion protocol provided elemental analysis for identifying and inferring the intensity of soil forming processes. The dominant soil forming factors include 1) organic matter accumulation, 2) clay eluviation-illuviation, 3) acidification, 4) base cation accumulation in the A horizons by the forest vegetation, 5) Fe-oxyhydroxide formation, and 6) clay mineral synthesis. Two soils were developed entirely in Peoria loess and two soils were developed in Peoria Loess overlying Ordovician limestone residuum. Ecological site descriptions provide land managers information for evaluating land suitability and the capability to implement different management activities without ecosystem disturbance. Best management practices for the described landforms and based on their Ecological Site Descriptions are presented.
文摘Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties for agriculture, forestry, or wild-life habitat. The typical practice of gypsum application is problematic given inability to provide drainage. Natraqualfs located in southeastern Missouri present an acid argillic horizon superimposed on a natric horizon, where the exchangeable sodium percentage and an alkaline reaction are characteristic attributes. Ferrolysis is an active soil process that is slowly degrading the natric horizon because of exchangeable Al<sup>3+</sup> and H<sup>+</sup> generation and re-stabilization of the soil structure, permitting leaching of the sodium.
文摘Nitrogen transport from agriculture production fields raises the specter of environmental degradation of freshwater resources. Our objectives were to document and evaluate nitrate-N, ammonium-N, phosphorus and other nutrients emanating from a 40-ha controlled subsurface irrigation drainage technology coupled in series with a denitrification bioreactor. The intent of the denitrification bioreactor is to create an environment for anoxic microbial populations to support denitrification. We monitored the tile-drainage effluent and denitrification bioreactor water chemistry under a corn-soybean rotation to estimate the nutrient concentrations and the competence of the denitrification bioreactor to foster denitrification. Nitrate-N bearing tile drainage effluents ranged from less than 1.5 to 109 mg NO3- -N/L, with the nitrate concentration differences attributed primarily to the: 1) timing of nitrogen fertilization for corn, 2) soil mineralization and residue decomposition, and 3) intense rainfall events. The denitrification bioreactor was highly effective in reducing drainage water nitrate-N concentrations providing the rate of water flow through the denitrification bioreactor permitted sufficient time for equilibrium to be attained for the nitrate reduction reactions. The nitrate-N concentrations entering the denitrification bioreactor ranged from 0.4 to 103 mg NO3-?-N/L in 2018, whereas the outlet nitrate concentrations typically ranged from 0.3 to 5.2 mg NO3- -N/L in 2018. Nitrate tile-drainage effluent concentrations in 2019 were marginal, given soybeans obtain nitrogen from biological nitrogen fixation. Nutrient uptake by corn reduced the soil nitrate leaching pool and created nitrogen-bearing biomass, features important for formulating best management practices.
文摘Soil aluminum phytotoxicity has been a major research area since the inception of modern soil science. Acid soils, which typically manifest plant aluminum toxicity, are frequently dedicated to food production, thus yield and quality reductions influence food security. This manuscript reviews our modern understanding of 1) soil aluminum hydrolysis and polymerization, 2) aluminum complexation with inorganic and organic anions, 3) aluminum interference with vital plant physiological processes, 4) aluminum and forest ecosystem productivity, and 5) demonstrates the software simulation of aluminum reactivity and its role in predicting soil behavior. The manuscript also provides a perspective for future soil-aluminum research critical to maintaining food security and food quality.
文摘Many Missouri forest soils exhibit fragipans, which influence soil productivity, ecosystem services and land management. Fragipan bearing soils tend to occur where loess thickness is moderate (1 to 2 meters) or where the soil profile exhibits evidence of mass wasting of weathered limestone residuum. Consensus is consolidating around the self-weight collapse of loess and residuum after repeated wetting and desiccation. The use of gravel as an indicator of parent material differences and its correlation with fragipan development is not perfectly aligned, thus although most fragipans do exhibit a bisequal soil profile, the placement of the lithologic discontinuity is difficult given mass wasting, eluviation-illuviation, side slopes, and other soil processes that contribute to increasing the bulk density and conferring strength. Fragipan genesis is evolving;however, research involving Ecosystem Site Descriptions are a fusion of a land parcel’s soil properties, vegetational community, hydrology, and climate to guide land management. Ecological Site Descriptions associated with fragipan bearing soils are necessary, especially when making land management decisions.
文摘Arsenic contamination of water,soil and food is a global concern.Rice(Oryza sativa)is uniquely involved because rice is a major staple food and its culture in anaerobic soil promotes arsenic accumulation.This manuscript attempts to apprise our current understanding of arsenic in rice in terms of:(i)the severity of the arsenic problem,(ii)the various irrigation technologies being advanced to mitigate arsenic rice accumulation,and(iii)the potential for emerging water conserving irrigation systems to reduce aquifer overdraft.The leading contenders to mitigate arsenic accumulation include(i)plant breeding,(ii)irrigation technologies,(iii)soil amendments that restrict arsenic bioavailability,and(iv)groundwater purification.Recent research involving(i)wetting and drying irrigation and(ii)furrow irrigation typically conserve water and inhibit arsenic accumulation.In Missouri,furrow irrigation generally reduced rice seed arsenic concentrations to less than 0.05 mg∙kg−1.Plant breeding to both limit arsenic accumulation and tolerate increased temperatures show promise,yet detailed research needs to be expanded.
文摘The Mississippi River watershed encompasses a substantial portion of the central United States,receiving effluent from soil runoff,urban and industrial centers.In Missouri,two soil series,with two pedons per series,located on the Mississippi River annual floodplain were morphologically described,classified,and chemically characterized.Aqua regia digestion and sodium acetate extractions were performed to assess the concentrations of 20 elements.A special emphasis was devoted to lead,cadmium,and zinc as these elements are commonly associated with heavy metal pollution.Cadmium was the only element showing an elevated concentration on one of the soil series.The pollution index and enrichment factor values suggested“cadmium impacted soils”.The elements used for geochemical background concentrations were determined using adjacent floodplain soils not experiencing annual Mississippi River flooding.However,geochemical background concentrations for cadmium were smaller than the sampled Mississippi River floodplain soils.Thus,the pollution index and the enrichment factor may have indicated“cadmium impacted soils”;however,the main difference is the soils used for the geochemical background soils and the Mississippi River floodplain soils simply exhibited slightly different cadmium concentrations.We conclude that cadmium may be accumulating in these annual flood prone soils;however,the intensity of the current cadmium accumulations is not appreciably above values that would warrant immediate remediation.
