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King WL, Richards SC, Kaminsky LM, Bradley BA, Kaye JP, Bell TH. Leveraging microbiome rediversification for the ecological rescue of soil function. Environ Microbiome 2023; 18:7. [PMID: 36691096 PMCID: PMC9872425 DOI: 10.1186/s40793-023-00462-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Global biodiversity losses threaten ecosystem services and can impact important functional insurance in a changing world. Microbial diversity and function can become depleted in agricultural systems and attempts to rediversify agricultural soils rely on either targeted microbial introductions or retaining natural lands as biodiversity reservoirs. As many soil functions are provided by a combination of microbial taxa, rather than outsized impacts by single taxa, such functions may benefit more from diverse microbiome additions than additions of individual commercial strains. In this study, we measured the impact of soil microbial diversity loss and rediversification (i.e. rescue) on nitrification by quantifying ammonium and nitrate pools. We manipulated microbial assemblages in two distinct soil types, an agricultural and a forest soil, with a dilution-to-extinction approach and performed a microbiome rediversification experiment by re-introducing microorganisms lost from the dilution. A microbiome water control was included to act as a reference point. We assessed disruption and potential restoration of (1) nitrification, (2) bacterial and fungal composition through 16S rRNA gene and fungal ITS amplicon sequencing and (3) functional genes through shotgun metagenomic sequencing on a subset of samples. RESULTS Disruption of nitrification corresponded with diversity loss, but nitrification was successfully rescued in the rediversification experiment when high diversity inocula were introduced. Bacterial composition clustered into groups based on high and low diversity inocula. Metagenomic data showed that genes responsible for the conversion of nitrite to nitrate and taxa associated with nitrogen metabolism were absent in the low diversity inocula microcosms but were rescued with high diversity introductions. CONCLUSIONS In contrast to some previous work, our data suggest that soil functions can be rescued by diverse microbiome additions, but that the concentration of the microbial inoculum is important. By understanding how microbial rediversification impacts soil microbiome performance, we can further our toolkit for microbial management in human-controlled systems in order to restore depleted microbial functions.
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Affiliation(s)
- William L King
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, 317 Buckhout Lab, University Park, PA, 16802, USA
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Sarah C Richards
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, 317 Buckhout Lab, University Park, PA, 16802, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA
- Intercollege Graduate Degree Program in International Agriculture and Development, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Laura M Kaminsky
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, 317 Buckhout Lab, University Park, PA, 16802, USA
| | - Brosi A Bradley
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Jason P Kaye
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Terrence H Bell
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, 317 Buckhout Lab, University Park, PA, 16802, USA.
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Intercollege Graduate Degree Program in International Agriculture and Development, The Pennsylvania State University, University Park, PA, 16802, USA.
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Zhang Z, Kaye JP, Bradley BA, Amsili JP, Suseela V. Cover crop functional types differentially alter the content and composition of soil organic carbon in particulate and mineral-associated fractions. Glob Chang Biol 2022; 28:5831-5848. [PMID: 35713156 PMCID: PMC9545985 DOI: 10.1111/gcb.16296] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/15/2022] [Accepted: 04/30/2022] [Indexed: 06/01/2023]
Abstract
Cover crops (CCs) can increase soil organic carbon (SOC) sequestration by providing additional OC residues, recruiting beneficial soil microbiota, and improving soil aggregation and structure. The various CC species that belong to distinct plant functional types (PFTs) may differentially impact SOC formation and stabilization. Biogeochemical theory suggests that selection of PFTs with distinct litter quality (C:N ratio) should influence the pathways and magnitude of SOC sequestration. Yet, we lack knowledge on the effect of CCs from different PFTs on the quantity and composition of physiochemical pools of SOC. We sampled soils under monocultures of three CC PFTs (legume [crimson clover]; grass [triticale]; and brassica [canola]) and a mixture of these three species, from a long-term CC experiment in Pennsylvania, USA. We measured C content in bulk soil and C content and composition in contrasting physical fractions: particulate organic matter, POM; and mineral-associated organic matter, MAOM. The bulk SOC content was higher in all CC treatments compared to the fallow. Compared to the legume, monocultures of grass and brassica with lower litter quality (wider C:N) had higher proportion of plant-derived C in POM, indicating selective preservation of complex structural plant compounds. In contrast, soils under legumes had greater accumulation of microbial-derived C in MAOM. Our results for the first time, revealed that the mixture contributed to a higher concentration of plant-derived compounds in POM relative to the legume, and a greater accumulation of microbial-derived C in MAOM compared to monocultures of grass and brassica. Mixtures with all three PFTs can thus increase the short- and long-term SOC persistence balancing the contrasting effects on the chemistries in POM and MAOM imposed by monoculture CC PFTs. Thus, despite different cumulative C inputs in CC treatments from different PFTs, the total SOC stocks did not vary between CC PFTs, rather PFTs impacted whether C accumulated in POM or MAOM fractions. This highlights that CCs of different PFTs may shift the dominant SOC formation pathways (POM vs. MAOM), subsequently impacting short- and long-term SOC stabilization and stocks. Our work provides a strong applied field test of biogeochemical theory linking litter quality to pathways of C accrual in soil.
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Affiliation(s)
- Ziliang Zhang
- Department of Plant & Environmental SciencesClemson UniversityClemsonSouth CarolinaUSA
- Institute for Sustainability, Energy, and EnvironmentUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Jason P. Kaye
- Department of Ecosystem Science & ManagementPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Brosi A. Bradley
- Department of Ecosystem Science & ManagementPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
| | - Joseph P. Amsili
- Department of Ecosystem Science & ManagementPennsylvania State UniversityUniversity ParkPennsylvaniaUSA
- Section of Soil and Crop Sciences, School of Integrative Plant ScienceCornell UniversityIthacaNYUSA
| | - Vidya Suseela
- Department of Plant & Environmental SciencesClemson UniversityClemsonSouth CarolinaUSA
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Stratton CA, Ray S, Bradley BA, Kaye JP, Ali JG, Murrell EG. Nutrition vs association: plant defenses are altered by arbuscular mycorrhizal fungi association not by nutritional provisioning alone. BMC Plant Biol 2022; 22:400. [PMID: 35974331 PMCID: PMC9380362 DOI: 10.1186/s12870-022-03795-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND While it is known that arbuscular mycorrhizal fungi (AMF) can improve nutrient acquisition and herbivore resistance in crops, the mechanisms by which AMF influence plant defense remain unknown. Plants respond to herbivory with a cascade of gene expression and phytochemical biosynthesis. Given that the production of defensive phytochemicals requires nutrients, a commonly invoked hypothesis is that the improvement to plant defense when grown with AMF is simply due to an increased availability of nutrients. An alternative hypothesis is that the AMF effect on herbivory is due to changes in plant defense gene expression that are not simply due to nutrient availability. In this study, we tested whether changes in plant defenses are regulated by nutritional provisioning alone or the response of plant to AMF associations. Maize plants grown with or without AMF and with one of three fertilizer treatments (standard, 2 × nitrogen, or 2 × phosphorous) were infested with fall armyworm (Spodoptera frugiperda; FAW) for 72 h. We measured general plant characteristics (e.g. height, number of leaves), relative gene expression (rtPCR) of three defensive genes (lox3, mpi, and pr5), total plant N and P nutrient content, and change in FAW mass per plant. RESULTS We found that AMF drove the defense response of maize by increasing the expression of mpi and pr5. Furthermore, while AMF increased the total phosphorous content of maize it had no impact on maize nitrogen. Fertilization alone did not alter upregulation of any of the 3 induced defense genes tested, suggesting the mechanism through which AMF upregulate defenses is not solely via increased N or P plant nutrition. CONCLUSION This work supports that maize defense may be optimized by AMF associations alone, reducing the need for artificial inputs when managing FAW.
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Affiliation(s)
- Chase A Stratton
- The Land Institute, 2440 E Water Well Rd, Salina, KS, 67401, USA.
| | - Swayamjit Ray
- Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Brosi A Bradley
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, 16802, USA
| | - Jason P Kaye
- Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, 16802, USA
| | - Jared G Ali
- Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Ebony G Murrell
- The Land Institute, 2440 E Water Well Rd, Salina, KS, 67401, USA
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King WL, Kaminsky LM, Richards SC, Bradley BA, Kaye JP, Bell TH. Farm-scale differentiation of active microbial colonizers. ISME Commun 2022; 2:39. [PMID: 37938671 PMCID: PMC9723676 DOI: 10.1038/s43705-022-00120-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 03/22/2022] [Accepted: 03/22/2022] [Indexed: 06/17/2023]
Abstract
Microbial movement is important for replenishing lost soil microbial biodiversity and driving plant root colonization, particularly in managed agricultural soils, where microbial diversity and composition can be disrupted. Despite abundant survey-type microbiome data in soils, which are obscured by legacy DNA and microbial dormancy, we do not know how active microbial pools are shaped by local soil properties, agricultural management, and at differing spatial scales. To determine how active microbial colonizers are shaped by spatial scale and environmental conditions, we deployed microbial traps (i.e. sterile soil enclosed by small pore membranes) containing two distinct soil types (forest; agricultural), in three neighboring locations, assessing colonization through 16S rRNA gene and fungal ITS amplicon sequencing. Location had a greater impact on fungal colonizers (R2 = 0.31 vs. 0.26), while the soil type within the microbial traps influenced bacterial colonizers more (R2 = 0.09 vs. 0.02). Bacterial colonizers showed greater colonization consistency (within-group similarity) among replicate communities. Relative to bacterial colonizers, fungal colonizers shared a greater compositional overlap to sequences from the surrounding local bulk soil (R2 = 0.08 vs. 0.29), suggesting that these groups respond to distinct environmental constraints and that their in-field management may differ. Understanding how environmental constraints and spatial scales impact microbial recolonization dynamics and community assembly are essential for identifying how soil management can be used to shape agricultural microbiomes.
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Affiliation(s)
- William L King
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Laura M Kaminsky
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Sarah C Richards
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, 16802, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA
- Intercollege Graduate Degree Program in International Agriculture and Development, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Brosi A Bradley
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Jason P Kaye
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Terrence H Bell
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park, PA, 16802, USA.
- Intercollege Graduate Degree Program in International Agriculture and Development, The Pennsylvania State University, University Park, PA, 16802, USA.
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Saha D, Kaye JP, Bhowmik A, Bruns MA, Wallace JM, Kemanian AR. Organic fertility inputs synergistically increase denitrification-derived nitrous oxide emissions in agroecosystems. Ecol Appl 2021; 31:e02403. [PMID: 34231260 DOI: 10.1002/eap.2403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 12/23/2020] [Accepted: 03/03/2021] [Indexed: 06/13/2023]
Abstract
Soil fertility in organic agriculture relies on microbial cycling of nutrient inputs from legume cover crops and animal manure. However, large quantities of labile carbon (C) and nitrogen (N) in these amendments may promote the production and emission of nitrous oxide (N2 O) from soils. Better ecological understanding of the N2 O emission controls may lead to new management strategies to reduce these emissions. We measured soil N2 O emission for two growing seasons in four corn-soybean-winter grain rotations with tillage, cover crop, and manure management variations typical of organic agriculture in temperate and humid North America. To identify N2 O production pathways and mitigation opportunities, we supplemented N2 O flux measurements with determinations of N2 O isotopomer composition and microbiological genomic DNA abundances in microplots where we manipulated cover crop and manure additions. The N input from legume-rich cover crops and manure prior to corn planting made the corn phase the main source of N2 O emissions, averaging 9.8 kg/ha of N2 O-N and representing 80% of the 3-yr rotations' total emissions. Nitrous oxide emissions increased sharply when legume cover crop and manure inputs exceeded 1.8 and 4 Mg/ha (dry matter), respectively. Removing the legume aboveground biomass before corn planting to prevent co-location of fresh biomass and manure decreased N2 O emissions by 60% during the corn phase. The co-occurrence of peak N2 O emission and high carbon dioxide emission suggests that oxygen (O2 ) consumption likely caused hypoxia and bacterial denitrification. This interpretation is supported by the N2 O site preference values trending towards denitrification during peak emissions with limited N2 O reduction, as revealed by the N2 O δ15 N and δ18 O and the decrease in clade I nosZ gene abundance following incorporation of cover crops and manure. Thus, accelerated microbial O2 consumption seems to be a critical control of N2 O emissions in systems with large additions of decomposable C and N substrates. Because many agricultural systems rely on combined fertility inputs from legumes and manures, our research suggests that controlling the rate and timing of organic input additions, as well as preventing the co-location of legume cover crops and manure, could mitigate N2 O emissions.
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Affiliation(s)
- Debasish Saha
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Jason P Kaye
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Arnab Bhowmik
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Mary Ann Bruns
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - John M Wallace
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Armen R Kemanian
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
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Morris AH, Isbell SA, Saha D, Kaye JP. Mitigating nitrogen pollution with under-sown legume-grass cover crop mixtures in winter cereals. J Environ Qual 2021; 50:324-335. [PMID: 33410518 DOI: 10.1002/jeq2.20193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Nitrogen (N) pollution from N inputs to agricultural soils contributes to widespread eutrophication and global climate change. One period susceptible to N losses is between winter grain harvest in summer and corn planting in spring in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-winter grain rotation. Cover crops used to immobilize N during this period often depend on tillage, which can exacerbate N losses. Therefore, we evaluated whether reduced-till cover crops could decrease nitrate (NO3 - ) leaching and nitrous oxide (N2 O) emissions during this period. We tested this strategy in a cropping systems experiment on a 4-ha plot in central Pennsylvania over 2 yr. This experiment compared a clover (Trifolium pratense L.)-timothy (Phleum pratense L.) cover crop no-till underseeded into a standing spelt crop with a vetch (Vicia villosa Roth)-triticale (× Triticosecale Wittm. ex A. Camus) cover crop established with tillage after spelt harvest. These systems were compared based on fortnightly N2 O emissions using static chambers (n = 4 per six sample dates) and potential NO3 - leaching using anion resin bags (n = 4 per system per year). Reduced-till cover crops minimized peak N2 O emissions during the fall compared with tilled cover crops. However, reduced-till cover crops did not decrease potentially leachable NO3 - relative to tilled cover crops despite decreases in soil inorganic N. Cover crop N isotopes revealed that clover N may have mineralized and leached over the winter. Our results suggest that reduced-till cover crops can decrease N2 O emissions to mitigate the climate impact of agriculture but that winter-hardy cover crops should be chosen to mitigate leaching.
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Affiliation(s)
- Andrew H Morris
- Institute of Ecology and Evolution, Dep. of Biology, Univ. of Oregon, Eugene, OR, 97403, USA
| | - Sarah A Isbell
- Dep. of Ecosystem Science and Management, The Pennsylvania State Univ., University Park, PA, 16802, USA
| | - Debasish Saha
- Biosystems Engineering and Soil Science, The Univ. of Tennessee, Knoxville, TN, 37996, USA
| | - Jason P Kaye
- Dep. of Ecosystem Science and Management, The Pennsylvania State Univ., University Park, PA, 16802, USA
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Isbell SA, Bradley BA, Morris AH, Wallace JM, Kaye JP. Nitrogen dynamics in grain cropping systems integrating multiple ecologically based management strategies. Ecosphere 2021. [DOI: 10.1002/ecs2.3380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Sarah A. Isbell
- Ecosystem Science and Management Department The Pennsylvania State University University Park Pennsylvania16802USA
| | - Brosi A. Bradley
- Ecosystem Science and Management Department The Pennsylvania State University University Park Pennsylvania16802USA
| | - Andrew H. Morris
- Department of Biology University of Oregon Eugene Oregon97403USA
| | - John M. Wallace
- Plant Science Department The Pennsylvania State University University Park Pennsylvania16802USA
| | - Jason P. Kaye
- Ecosystem Science and Management Department The Pennsylvania State University University Park Pennsylvania16802USA
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Baraibar B, Murrell EG, Bradley BA, Barbercheck ME, Mortensen DA, Kaye JP, White CM. Cover crop mixture expression is influenced by nitrogen availability and growing degree days. PLoS One 2020; 15:e0235868. [PMID: 32716963 PMCID: PMC7384630 DOI: 10.1371/journal.pone.0235868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/24/2020] [Indexed: 12/05/2022] Open
Abstract
Cover crop mixtures can provide multiple ecosystem services but provisioning of these services is contingent upon the expression of component species in the mixture. From the same seed mixture, cover crop mixture expression varied greatly across farms and we hypothesized that this variation was correlated with soil inorganic nitrogen (N) concentrations and growing degree days. We measured fall and spring biomass of a standard five-species mixture of canola (Brassica napus L.), Austrian winter pea (Pisum sativum L), triticale (x Triticosecale Wittm.), red clover (Trifolium pratense L.) and crimson clover (Trifolium incarnatum L.) seeded at a research station and on 8 farms across Pennsylvania and New York in two consecutive years. At the research station, soil inorganic N (soil iN) availablity and cumulative fall growing degree days (GDD) were experimentally manipulated through fertilizer additions and planting date. Farmers seeded the standard mixture and a "farm-tuned" mixture of the same five species with component seeding rates adjusted to achieve farmer-desired services. We used Structural Equation Modeling to parse out the effects of soil iN and GDD on cover crop mixture expression. When soil iN and fall GDD were high, canola dominated the mixture, especially in the fall. Low soil iN favored legume species while a shorter growing season favored triticale. Changes in seeding rates influenced mixture composition in fall and spring but interacted with GDD to determine the final expression of the mixture. Our results show that when soil iN availability is high at the time of cover crop planting, highly competitive species can dominate mixtures which could potentially decrease services provided by other species, especially legumes. Early planting dates can exacerbate the dominance of aggressive species. Managers should choose cover crop species and seeding rates according to their soil iN and GDD to ensure the provision of desired services.
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Affiliation(s)
- Barbara Baraibar
- Department of Plant Science, Penn State University, University Park, State College, Pennsylvania, United States of America
| | - Ebony G. Murrell
- Department of Ecosystem Science and Management, Penn State University, University Park, State College, Pennsylvania, United States of America
| | - Brosi A. Bradley
- Department of Ecosystem Science and Management, Penn State University, University Park, State College, Pennsylvania, United States of America
| | - Mary E. Barbercheck
- Department of Entomology, Penn State University, University Park, State College, Pennsylvania, United States of America
| | - David A. Mortensen
- Department of Plant Science, Penn State University, University Park, State College, Pennsylvania, United States of America
| | - Jason P. Kaye
- Department of Ecosystem Science and Management, Penn State University, University Park, State College, Pennsylvania, United States of America
| | - Charles M. White
- Department of Plant Science, Penn State University, University Park, State College, Pennsylvania, United States of America
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Kizewski FR, Kaye JP, Martínez CE. Nitrate transformation and immobilization in particulate organic matter incubations: Influence of redox, iron and (a)biotic conditions. PLoS One 2019; 14:e0218752. [PMID: 31276538 PMCID: PMC6611582 DOI: 10.1371/journal.pone.0218752] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 06/09/2019] [Indexed: 11/18/2022] Open
Abstract
Nitrate can be reduced to other N inorganic species via denitrification and incorporated into organic matter by immobilization; however, the effect of biotic/abiotic and redox condition on immobilization and denitrification processes from a single system are not well documented. We hypothesize nitrate (NO3-) transformation pathways leading to the formation of dissolved- and solid-phase organic N are predominantly controlled by abiotic reactions, but the formation of soluble inorganic N species is controlled by redox condition. In this study, organic matter in the form of leaf compost (LC) was spiked with 15NO3- and incubated under oxic/anoxic and biotic/abiotic conditions at pH 6.5. We seek to understand how variations in environmental conditions impact NO3- transformation pathways through laboratory incubations. We find production of NH4+ is predominantly controlled by redox whereas NO3- conversion to dissolved organic nitrogen (DON) and immobilization in solid-phase N are predominantly controlled by abiotic processes. Twenty % of added 15N-NO3- was incorporated into DON under oxic conditions, with abiotic processes accounting for 85% of the overall incorporation. Nitrogen immobilization processes resulted in N concentrations of 4.1–6.6 μg N (g leaf compost)-1, with abiotic processes accounting for 100% and 66% of the overall (biotic+abiotic) N immobilization under anoxic and oxic conditions, respectively. 15N-NMR spectroscopy suggests 15NO3- was immobilized into amide/aminoquinones and nitro/oxime under anoxic conditions. A fraction of the NH4+ was produced abiotically under anoxic conditions (~10% of the total NH4+ production) although biotic organic N mineralization contributed to most of NH4+ production. Our results also indicate Fe(II) did not act as an electron source in biotic-oxic incubations; however, Fe(II) provided electrons for NO3- reduction in biotic-anoxic incubations although it was not the sole electron source. It is clear that, under the experimental conditions of this investigation, abiotic and redox processes play important roles in NO3- transformations. As climatic conditions change (e.g., frequency/intensity of rainfall), abiotic reactions that shift transformation pathways and N species concentrations from those controlled by biota might become more prevalent.
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Affiliation(s)
- Fiona R. Kizewski
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, United States of America
| | - Jason P. Kaye
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, United States of America
| | - Carmen Enid Martínez
- Soil and Crop Sciences, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States of America
- * E-mail:
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Kaye JP, Kaye MW, Hart SC, Covington WW, Fulé PZ. Slow carbon and nutrient accumulation in trees established following fire exclusion in the southwestern United States. Ecol Appl 2016; 26:2400-2411. [PMID: 27859967 DOI: 10.1002/eap.1407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 07/03/2016] [Accepted: 07/12/2016] [Indexed: 06/06/2023]
Abstract
Increasing tree density that followed fire exclusion after the 1880s in the southwestern United States may have also altered nutrient cycles and led to a carbon (C) sink that constitutes a significant component of the U.S. C budget. Yet, empirical data quantifying century-scale changes in C or nutrients due to fire exclusion are rare. We used tree-ring reconstructions of stand structure from five ponderosa pine-dominated sites from across northern Arizona to compare live tree C, nitrogen (N), and phosphorus (P) storage between the 1880s and 1990s. Live tree biomass in the 1990s contained up to three times more C, N, and P than in 1880s. However, the increase in C storage was smaller than values used in recent U.S. C budgets. Furthermore, trees that had established prior to the 1880s accounted for a large fraction (28-66%) of the C, N, and P stored in contemporary stands. Overall, our century-scale analysis revealed that forests of the 1880s were on a trajectory to accumulate C and nutrients in trees even in the absence of fire exclusion, either because growing conditions became more favorable after the 1880s or because forests in the 1880s included age or size cohorts poised for accelerated growth. These results may lead to a reduction in the C sink attributed to fire exclusion, and they refine our understanding of reference conditions for restoration management of fire-prone forests.
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Affiliation(s)
- Jason P Kaye
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Margot W Kaye
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Stephen C Hart
- School of Natural Sciences and Sierra Nevada Research Institute, University of California, Merced, California, 95344, USA
| | - W Wallace Covington
- Ecological Restoration Institute and School of Forestry, Northern Arizona University, Flagstaff, Arizona, 86011, USA
| | - Peter Z Fulé
- School of Forestry, Northern Arizona University, Flagstaff, Arizona, 86011, USA
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Affiliation(s)
- Denise M. Finney
- Department of Biology Ursinus College 601 E. Main St. Collegeville PA 19426 USA
| | - Jason P. Kaye
- Department of Ecosystem Science and Management Penn State University 116 ASI University Park PA 16802 USA
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Finney DM, Eckert SE, Kaye JP. Drivers of nitrogen dynamics in ecologically based agriculture revealed by long-term, high-frequency field measurements. Ecol Appl 2015; 25:2210-2227. [PMID: 26910950 DOI: 10.1890/14-1357.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nitrogen (N) loss from agriculture impacts ecosystems worldwide. One strategy to mitigate these losses, ecologically based nutrient management (ENM), seeks to recouple carbon (C) and N cycles to reduce environmental losses and supply N to cash crops. However, our capacity to apply ENM is limited by a lack of field-based high-resolution data on N dynamics in actual production contexts. We used data from a five-year study of organic cropping systems to investigate soil inorganic N (SIN) variability and nitrate (NO3-) leaching in ENM. Four production systems initiated in 2007 and 2008 in central Pennsylvania varied in crop rotation, timing and intensity of tillage, inclusion of fallow periods, and N inputs. Extractable SIN was measured fortnightly from March through November throughout the experiment, and NO3- N concentration below the rooting zone was sampled with lysimeters during the first year of the 2008 start. We used recursive partitioning models to assess the importance of management and environmental factors to SIN variability and NO3- leaching and identify interactions between influential variables. Air temperature and tillage were the most important drivers of SIN across systems. The highest SIN concentrations occurred when the average air temperature three weeks prior to measurement was above 21 degrees C. Above this temperature and within 109 days of moldboard plowing, average SIN concentrations were 22.1 mg N/kg soil; 109 days or more past plowing average SIN dropped to 7.7 mg N/kg soil. Other drivers of SIN dynamics were N available from manure and cover crops. Highest average leachate NO3- N concentrations (15.2 ppm) occurred in fall and winter when SIN was above 4.9 mg/kg six weeks prior to leachate collection. Late season tillage operations leading to elevated SIN and leachate NO3- N concentrations were a strategy to reduce weeds while meeting consumer demand for organic products. Thus, while tillage that incorporates organic N inputs preceding cash crops can promote synchrony of N mineralization and crop demand, late or post-season tillage promotes NO3 leaching by stimulating SIN pulses that are asynchronous with plant uptake.
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Lewis DB, Castellano MJ, Kaye JP. Forest succession, soil carbon accumulation, and rapid nitrogen storage in poorly remineralized soil organic matter. Ecology 2014. [DOI: 10.1890/13-2196.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Lewis DB, Kaye JP, Kinzig AP. Legacies of agriculture and urbanization in labile and stable organic carbon and nitrogen in Sonoran Desert soils. Ecosphere 2014. [DOI: 10.1890/es13-00400.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Kurth VJ, Hart SC, Ross CS, Kaye JP, Fulé PZ. Stand-replacing wildfires increase nitrification for decades in southwestern ponderosa pine forests. Oecologia 2014; 175:395-407. [PMID: 24549939 DOI: 10.1007/s00442-014-2906-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 02/07/2014] [Indexed: 10/25/2022]
Abstract
Stand-replacing wildfires are a novel disturbance within ponderosa pine (Pinus ponderosa) forests of the southwestern United States, and they can convert forests to grasslands or shrublands for decades. While most research shows that soil inorganic N pools and fluxes return to pre-fire levels within a few years, we wondered if vegetation conversion (ponderosa pine to bunchgrass) following stand-replacing fires might be accompanied by a long-term shift in N cycling processes. Using a 34-year stand-replacing wildfire chronosequence with paired, adjacent unburned patches, we examined the long-term dynamics of net and gross nitrogen (N) transformations. We hypothesized that N availability in burned patches would become more similar to those in unburned patches over time after fire as these areas become re-vegetated. Burned patches had higher net and gross nitrification rates than unburned patches (P < 0.01 for both), and nitrification accounted for a greater proportion of N mineralization in burned patches for both net (P < 0.01) and gross (P < 0.04) N transformation measurements. However, trends with time-after-fire were not observed for any other variables. Our findings contrast with previous work, which suggested that high nitrification rates are a short-term response to disturbance. Furthermore, high nitrification rates at our site were not simply correlated with the presence of herbaceous vegetation. Instead, we suggest that stand-replacing wildfire triggers a shift in N cycling that is maintained for at least three decades by various factors, including a shift from a woody to an herbaceous ecosystem and the presence of fire-deposited charcoal.
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Affiliation(s)
- Valerie J Kurth
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011-5018, USA,
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Zhang Y, Qian Y, Bremer DJ, Kaye JP. Simulation of Nitrous Oxide Emissions and Estimation of Global Warming Potential in Turfgrass Systems Using the DAYCENT Model. J Environ Qual 2013; 42:1100-8. [PMID: 24216361 DOI: 10.2134/jeq2012.0486] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Nitrous oxide (NO) emissions are an important component of the greenhouse gas budget for turfgrasses. To estimate NO emissions and global warming potential, the DAYCENT ecosystem model was parameterized and applied to turfgrass ecosystems. The annual cumulative NO emissions predicted by the DAYCENT model were close to the measured emission rates of Kentucky bluegrass ( L.) sites in Colorado (within 16% of the observed values). For the perennial ryegrass ( L.) site in Kansas, the DAYCENT model initially overestimated the NO emissions for all treatments (urea and ammonium sulfate at 250 kg N ha yr and urea at 50 kg N ha yr) by about 200%. After including the effect of biological nitrification inhibition in the root exudate of perennial ryegrass, the DAYCENT model correctly simulated the NO emissions for all treatments (within 8% of the observed values). After calibration and validation, the DAYCENT model was used to simulate NO emissions and carbon sequestration of a Kentucky bluegrass lawn under a series of management regimes. The model simulation suggested that gradually reducing fertilization as the lawn ages from 0 to 50 yr would significantly reduce long-term NO emissions by approximately 40% when compared with applying N at a constant rate of 150 kg N ha yr. Our simulation indicates that a Kentucky bluegrass lawn in Colorado could change from a sink to a weak source of greenhouse gas emissions 20 to 30 yr after establishment.
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Abstract
Experiments suggest that plants and soil microorganisms are both limited by inorganic nitrogen, even on relatively fertile sites. Consequently, plants and soil microorganisms may compete for nitrogen. While past research has focused on competition for inorganic nitrogen, recent studies have found that plants/mycorrhizae in a wide range of ecosystems can use organic nitrogen. A new view of competitive interactions between plants and soil microorganisms is necessary in ecosystem where plant uptake of organic nitrogen is observed.
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Affiliation(s)
- J P Kaye
- School of Forestry, College of Ecosystem Science and Management, Northern Arizona University, Flagstaff, AZ 86011-5018, USA
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Sponseller RA, Hall SJ, Huber DP, Grimm NB, Kaye JP, Clark CM, Collins SL. Variation in monsoon precipitation drives spatial and temporal patterns of Larrea tridentata growth in the Sonoran Desert. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.01979.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Hall SJ, Sponseller RA, Grimm NB, Huber D, Kaye JP, Clark C, Collins SL. Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran Desert. Ecol Appl 2011; 21:640-660. [PMID: 21639034 DOI: 10.1890/10-0758.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Rates of nitrogen (N) deposition have increased in arid and semiarid ecosystems, but few studies have examined the impacts of long-term N enrichment on ecological processes in deserts. We conducted a multiyear, nutrient-addition study within 15 Sonoran Desert sites across the rapidly growing metropolitan area of Phoenix, Arizona (USA). We hypothesized that desert plants and soils would be sensitive to N enrichment, but that these effects would vary among functional groups that differ in terms of physiological responsiveness, proximity to surface N sources, and magnitude of carbon (C) or water limitation. Inorganic N additions augmented net potential nitrification in soils, moreso than net potential N mineralization, highlighting the important role of nitrifying microorganisms in the nitrate economy of drylands. Winter annual plants were also responsive to nutrient additions, exhibiting a climate-driven cascade of resource limitation, from little to no production in seasons of low rainfall (winter 2006 and 2007), to moderate N limitation with average precipitation (winter 2009), to limitation by both N and P in a season of above-normal rainfall (winter 2008). Herbaceous production is a potentially important mechanism of N retention in arid ecosystems, capable of immobilizing an amount equal to or greater than that deposited annually to soils in this urban airshed. However, interannual variability in precipitation and abiotic processes that limit the incorporation of detrital organic matter into soil pools may limit this role over the long term. In contrast, despite large experimental additions of N and P over four years, growth of Larrea tridentata, the dominant perennial plant of the Sonoran Desert, was unresponsive to nutrient enrichment, even during wet years. Finally, there did not appear to be strong ecological interactions between nutrient addition and location relative to the city, despite the nearby activity of nearly four million people, perhaps due to loss or transfer pathways that limit long-term N enrichment of ecosystems by the urban atmosphere.
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Affiliation(s)
- Sharon J Hall
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501, USA.
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Esque TC, Kaye JP, Eckert SE, Defalco LA, Tracy CR. Short-term soil inorganic N pulse after experimental fire alters invasive and native annual plant production in a Mojave Desert shrubland. Oecologia 2010; 164:253-63. [PMID: 20419316 DOI: 10.1007/s00442-010-1617-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Accepted: 03/13/2010] [Indexed: 10/19/2022]
Abstract
Post-fire changes in desert vegetation patterns are known, but the mechanisms are poorly understood. Theory suggests that pulse dynamics of resource availability confer advantages to invasive annual species, and that pulse timing can influence survival and competition among species. Precipitation patterns in the American Southwest are predicted to shift toward a drier climate, potentially altering post-fire resource availability and consequent vegetation dynamics. We quantified post-fire inorganic N dynamics and determined how annual plants respond to soil inorganic nitrogen variability following experimental fires in a Mojave Desert shrub community. Soil inorganic N, soil net N mineralization, and production of annual plants were measured beneath shrubs and in interspaces during 6 months following fire. Soil inorganic N pools in burned plots were up to 1 g m(-2) greater than unburned plots for several weeks and increased under shrubs (0.5-1.0 g m(-2)) more than interspaces (0.1-0.2 g m(-2)). Soil NO(3) (-)-N (nitrate-N) increased more and persisted longer than soil NH(4) (+)-N (ammonium-N). Laboratory incubations simulating low soil moisture conditions, and consistent with field moisture during the study, suggest that soil net ammonification and net nitrification were low and mostly unaffected by shrub canopy or burning. After late season rains, and where soil inorganic N pools were elevated after fire, productivity of the predominant invasive Schismus spp. increased and native annuals declined. Results suggest that increased N availability following wildfire can favor invasive annuals over natives. Whether the short-term success of invasive species following fire will direct long-term species composition changes remains to be seen, yet predicted changes in precipitation variability will likely interact with N cycling to affect invasive annual plant dominance following wildfire.
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Affiliation(s)
- Todd C Esque
- US Geological Survey, Western Ecological Research Center, 160 N. Stephanie St., Henderson, NV 89074, USA.
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Dore S, Kolb TE, Montes-Helu M, Eckert SE, Sullivan BW, Hungate BA, Kaye JP, Hart SC, Koch GW, Finkral A. Carbon and water fluxes from ponderosa pine forests disturbed by wildfire and thinning. Ecol Appl 2010; 20:663-683. [PMID: 20437955 DOI: 10.1890/09-0934.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Disturbances alter ecosystem carbon dynamics, often by reducing carbon uptake and stocks. We compared the impact of two types of disturbances that represent the most likely future conditions of currently dense ponderosa pine forests of the southwestern United States: (1) high-intensity fire and (2) thinning, designed to reduce fire intensity. High-severity fire had a larger impact on ecosystem carbon uptake and storage than thinning. Total ecosystem carbon was 42% lower at the intensely burned site, 10 years after burning, than at the undisturbed site. Eddy covariance measurements over two years showed that the burned site was a net annual source of carbon to the atmosphere whereas the undisturbed site was a sink. Net primary production (NPP), evapotranspiration (ET), and water use efficiency were lower at the burned site than at the undisturbed site. In contrast, thinning decreased total ecosystem carbon by 18%, and changed the site from a carbon sink to a source in the first posttreatment year. Thinning also decreased ET, reduced the limitation of drought on carbon uptake during summer, and did not change water use efficiency. Both disturbances reduced ecosystem carbon uptake by decreasing gross primary production (55% by burning, 30% by thinning) more than total ecosystem respiration (TER; 33-47% by burning, 18% by thinning), and increased the contribution of soil carbon dioxide efflux to TER. The relationship between TER and temperature was not affected by either disturbance. Efforts to accurately estimate regional carbon budgets should consider impacts on carbon dynamics of both large disturbances, such as high-intensity fire, and the partial disturbance of thinning that is often used to prevent intense burning. Our results show that thinned forests of ponderosa pine in the southwestern United States are a desirable alternative to intensively burned forests to maintain carbon stocks and primary production.
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Affiliation(s)
- S Dore
- School of Forestry, Northern Arizona University, P.O. Box 15018, Flagstaff, Arizona 86011-5018, USA.
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Kaye JP, Majumdar A, Gries C, Buyantuyev A, Grimm NB, Hope D, Jenerette GD, Zhu WX, Baker L. Hierarchical Bayesian scaling of soil properties across urban, agricultural, and desert ecosystems. Ecol Appl 2008; 18:132-145. [PMID: 18372561 DOI: 10.1890/06-1952.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ecologists increasingly use plot-scale data to inform research and policy related to regional and global environmental change. For soil chemistry research, scaling from the plot to the region is especially difficult due to high spatial variability at all scales. We used a hierarchical Bayesian model of plot-scale soil nutrient pools to predict storage of soil organic carbon (oC), inorganic carbon (iC), total nitrogen (N), and available phosphorus (avP) in a 7962-km2 area including the Phoenix, Arizona, USA, metropolitan area and its desert and agricultural surroundings. The Bayesian approach was compared to a traditional approach that multiplied mean values for urban mesic residential, urban xeric residential, nonresidential urban, agricultural, and desert areas by the aerial coverage of each land-use type. Both approaches suggest that oC, N, and avP are correlated with each other and are higher (in g/m2) in mesic residential and agricultural areas than in deserts or xeric residential areas. In addition to traditional biophysical variables, cultural variables related to impervious surface cover, tree cover, and turfgrass cover were significant in regression models predicting the regional distribution of soil properties. We estimate that 1140 Gg of oC have accumulated in human-dominated soils of this region, but a significant portion of this new C has a very short mean residence time in mesic yards and agricultural soils. For N, we estimate that 130 Gg have accumulated in soils, which explains a significant portion of "missing N" observed in the regional N budget. Predictions for iC differed between the approaches because the Bayesian approach predicted iC as a function of elevation while the traditional approach employed only land use. We suggest that Bayesian scaling enables models that are flexible enough to accommodate the diverse factors controlling soil chemistry in desert, urban, and agricultural ecosystems and, thus, may represent an important tool for ecological scaling that spans land-use types. Urban planners and city managers attempting to reduce C emissions and N pollution should consider ways that landscape choices and impervious surface cover affect city-wide soil C, N, and P storage.
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Affiliation(s)
- J P Kaye
- Department of Crop and Soil Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Kaye JP, Groffman PM, Grimm NB, Baker LA, Pouyat RV. A distinct urban biogeochemistry? Trends Ecol Evol 2006; 21:192-9. [PMID: 16701085 DOI: 10.1016/j.tree.2005.12.006] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 11/24/2005] [Accepted: 12/20/2005] [Indexed: 11/16/2022]
Abstract
Most of the global human population lives in urban areas where biogeochemical cycles are controlled by complex interactions between society and the environment. Urban ecology is an emerging discipline that seeks to understand these interactions, and one of the grand challenges for urban ecologists is to develop models that encompass the myriad influences of people on biogeochemistry. We suggest here that existing models, developed primarily in unmanaged and agricultural ecosystems, work poorly in urban ecosystems because they do not include human biogeochemical controls such as impervious surface proliferation, engineered aqueous flow paths, landscaping choices, and human demographic trends. Incorporating these human controls into biogeochemical models will advance urban ecology and will require enhanced collaborations with engineers and social scientists.
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Affiliation(s)
- Jason P Kaye
- Department of Crop and Soil Sciences, 116 ASI Building, The Pennsylvania State University, University Park, PA 16802, USA.
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Affiliation(s)
- Jason P. Kaye
- College of Ecosystem Science and Management, School of Forestry, Northern Arizona University, Flagstaff, Arizona 86011, U.S.A
- Current Address: Department of Forest Sciences, Colorado State University, Fort Collins, CO 80523, U.S.A
- Address correspondence to J. P. Kaye, email
| | - Stephen C. Hart
- College of Ecosystem Science and Management, School of Forestry, Northern Arizona University, Flagstaff, Arizona 86011, U.S.A
| | - Richard C. Cobb
- College of Ecosystem Science and Management, School of Forestry, Northern Arizona University, Flagstaff, Arizona 86011, U.S.A
- Current Address: Department of Ecosystem Science, University of Maine at Orono, Nutting Hall, Orono, ME 04469–5755, U.S.A
| | - Joseph E. Stone
- College of Ecosystem Science and Management, School of Forestry, Northern Arizona University, Flagstaff, Arizona 86011, U.S.A
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Abstract
Fasting concentrations of plasma bilirubin were measured in 34 patients on admission to hospital and daily for 7 days after uncomplicated myocardial infarction. Mean concentrations increased significantly to reach maximum levels on the second day after admission, and fell during the following 5 days to reach the admission level by the 7th day. Unconjugated bilirubin accounted for most of this rise. Serum concentrations of free fatty acids (FFA), measured simultaneously in 12 patients, were highest within 12 hr of the onset of symptoms, when their level was significantly higher than at any time after the first day. It is suggested that the transient hyperbilirubinaemia after uncomplicated myocardial infarction is frequent and may result from interference by FFA with bilirubin metabolism.
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Cowan RE, Thompson RP, Kaye JP, Clark GM. The association between fasting hyperbilirubinaemia and serum non-esterified fatty acids in man. Clin Sci Mol Med 1977; 53:155-63. [PMID: 891104 DOI: 10.1042/cs0530155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. The concentrations of plasma total and unconjugated bilirubin and of serum nonesterified fatty acids (NEFA) have been measured in two healthy subjects during fasts of up to 21 h. 2. Fasting was either continuous or interrupted by various procedures that altered the concentrations of NEFA and total bilirubin. 3. When NEFA concentrations were increased by the administration of noradrenaline, heparin or caffeine, bilirubin concentrations also rose. 4. When NEFA concentrations were lowered by insulin, bilirubin concentrations fell. 5. Meals of 3-138 kJ and more, taken during the fasting period, lowered total bilirubin and NEFA concentrations in both subjects, whereas the effects of smaller meals were less consistent. 6. These studies demonstrate a statistically significant correlation between total bilirubin and NEFA during uninterrupted fasting and an association between these variables under other experimental conditions. They suggest that the control of bilirubin concentrations in the blood is linked to lipid metabolism.
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Abstract
A new method has been devised to study triglyceride-production rates in man. The clearance of plasma-triglyceride transported on very-low-density lipoproteins (V.L.D.I.) to peripheral tissues is inhibited by about 50 percent with protamine sulphate; and this results in a rise of blood-glycerides over 1 hour. In a group of nine patients with type-IV hypertriglyceridaemia (mean fasting glycerides 252 mg. per 100 ml.) the mean increment of plasma-triglycerides was 29.8 compared with 1.4 mg. per 100 ml. per hour for nine controls whose mean fasting glycerides had been only 105 mg. per 100 ml. Patients with fasting plasma-triglycerides greater than 400 mg. per 100 ml. showed a response to protamine more like controls. It is suggested that patients with type-IV hyperlipaemia and fasting levels of triglycerides less than 400 mg. per 100 ml. are secreting triglycerides into blood at greater rates than controls; whereas patients with sever hypertriglyceridaemia (levels greater than 400 mg. per 100 ml.) may have a defect of triglyceride clearance so that inhibition by protamine produces no further change in level of plasma glycerides.
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