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Norgaard AE, Lewis D, Borden KA, Krzic M, Carrillo J, Smukler SM. Trade-offs in organic nutrient management strategies across mixed vegetable farms in Southwest British Columbia. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2022. [DOI: 10.3389/fsufs.2022.706271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Balancing economic and environmental objectives can present trade-offs for organic farmers maximizing crop yields while maintaining core principles of ecology and health. A primary challenge for achieving this balance is nitrogen (N) and phosphorus (P) management. Meeting crop N requirements with compost can build soil carbon (C) and soil health but often over-applies P and increases soil P and associated environmental risks. Alternatively, high-N organic fertilizers can provide N without surplus P but can be expensive and lack C inputs that composts supply. We evaluated these potential trade-offs in 2-year field trials on 20 mixed vegetable farms across three regions of Southwest British Columbia, Canada, capturing a range of climatic-edaphic conditions and organic amendments. Three nutrient management strategies were evaluated: High Compost: compost applied to meet crop N removal, Low Compost + N: compost applied to meet crop P removal plus an organic fertilizer to meet crop N removal, and Typical: varying combinations of composts and/or organic fertilizers (“typical” nutrient application on the farm). Nutrient strategies were evaluated in terms of yield, input costs, and soil properties [permanganate oxidizable C (labile C responsive to soil management), and post-season available N and P]. Soil P was 21% higher with High Compost than Low Compost + N. In one region characterized by inexpensive but nutrient-rich composts and soils high in P, input costs were lowest with Typical, but in the second year, High Compost outperformed Typical in crop yield. Principal component analysis showed a divergence in post-season NO3- between nutrient strategies in relation to compost and soil properties: High Compost using high-N composts increased post-season NO3- (0–30 cm), whereas relative yields in High Compost tended to be higher on farms with lower soil C and lower C:N composts, while yields with Typical were higher under opposite conditions but associated with higher post-season NO3-. Combining input types (e.g., Low Compost + N) can meet environmental objectives in reducing surplus soil P without short-term yield or cost trade-offs compared to High Compost. However, maintaining soil C needs to be investigated to achieve effective ecological nutrient management in organic vegetable production with improved nutrient balances.
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Watson GP, Margenot AJ. Fruit lead concentrations of tomato (Solanum lycopersicum L.) grown in lead-contaminated soils are unaffected by phosphate amendments and can vary by season, but are below risk thresholds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 836:155076. [PMID: 35398426 DOI: 10.1016/j.scitotenv.2022.155076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 04/02/2022] [Accepted: 04/03/2022] [Indexed: 06/14/2023]
Abstract
Urban agriculture in post-industrial cities faces concerns on human health risks posed by elevated lead (Pb) concentrations of edible plant tissues grown in Pb-enriched soils. A recommended mitigation strategy to decrease soil Pb bioavailability to humans is the addition of soluble phosphate (PO43--P), but it is unclear if this strategy can also reduce crop Pb uptake and accumulation in edible tissues. Across urban agriculture sites in Chicago, Illinois (6 site-years) with elevated total soil Pb, we tested the hypothesized decrease in tomato fruit Pb following soil-based application of three phosphate-based mitigation amendments: triple superphosphate, composted biosolids, and air dried biosolids. Fruit Pb concentrations (mg Pb kg-1 dry mass) and loads (mg Pb m-2) were unaffected by mitigation amendments. However, fruit Pb concentrations were higher by an order of magnitude in 2020 (≥0.13 mg kg-1) compared to 2019 (0.01 mg kg-1) for two of the three sites. Though highly variable across site-years, the bioconcentration factor (BCF) of Pb from soil to fruit varied was unaffected by mitigation amendments. Relatively low BCF values were consistent with fruit Pb concentrations being below FAO/WHO risk limits. Collectively, our findings support previous propositions that fruits of plants grown in soils with elevated Pb generally pose lower risk to consumers. To mitigate health risks of consuming tomatoes grown in soils with Pb contamination, the seasonality of Pb uptake should be investigated, and greater focus should be placed on where tomatoes are grown rather than phosphate-based immobilization strategies originally designed to mitigate human bioavailability.
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Affiliation(s)
- George P Watson
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, United States of America
| | - Andrew J Margenot
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, United States of America; Agroecosystem Sustainability Center, Institute for Sustainability, Energy, and Environment, University of Illinois Urbana-Champaign, Urbana, IL 61801, United States of America.
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Zhao YH, Wang N, Yu MK, Yu JG, Xue LH. Rhizosphere and Straw Return Interactively Shape Rhizosphere Bacterial Community Composition and Nitrogen Cycling in Paddy Soil. Front Microbiol 2022; 13:945927. [PMID: 35875526 PMCID: PMC9301285 DOI: 10.3389/fmicb.2022.945927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/13/2022] [Indexed: 11/17/2022] Open
Abstract
Currently, how rice roots interact with straw return in structuring rhizosphere communities and nitrogen (N) cycling functions is relatively unexplored. In this study, paddy soil was amended with wheat straw at 1 and 2% w/w and used for rice growth. The effects of the rhizosphere, straw, and their interaction on soil bacterial community composition and N-cycling gene abundances were assessed at the rice maturity stage. For the soil without straw addition, rice growth, i.e., the rhizosphere effect, significantly altered the bacterial community composition and abundances of N-cycling genes, such as archaeal and bacterial amoA (AOA and AOB), nirK, and nosZ. The comparison of bulk soils between control and straw treatments showed a shift in bacterial community composition and decreased abundance of AOA, AOB, nirS, and nosZ, which were attributed to sole straw effects. The comparison of rhizosphere soils between control and straw treatments showed an increase in the nifH gene and a decrease in the nirK gene, which were attributed to the interaction of straw and the rhizosphere. The number of differentially abundant genera in bulk soils between control and straw treatments was 13-23, similar to the number of 16-22 genera in rhizosphere soil between control and straw treatment. However, the number of genera affected by the rhizosphere effect was much lower in soil amended with straw (3-4) than in soil without straw addition (9). Results suggest possibly more pronounced impacts of straw amendments in shaping soil bacterial community composition.
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Affiliation(s)
- Ya-Hui Zhao
- Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, P.R. China, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Ning Wang
- Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, P.R. China, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, China
| | - Meng-Kang Yu
- Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, P.R. China, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Henan Institute of Science and Technology, Xinxiang, China
| | - Jian-Guang Yu
- Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, P.R. China, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, China
| | - Li-Hong Xue
- Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, P.R. China, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, China
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4
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White KE, Brennan EB, Cavigelli MA, Smith RF. Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production. PLoS One 2022; 17:e0267757. [PMID: 35482753 PMCID: PMC9049554 DOI: 10.1371/journal.pone.0267757] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 04/15/2022] [Indexed: 11/25/2022] Open
Abstract
Efficient use of nitrogen (N) is essential to protect water quality in high-input organic vegetable production systems, but little is known about the long-term effects of organic management on N mass balances. We measured soil N and tabulated N inputs (organic fertilizers, compost, irrigation water, atmospheric deposition, cover crop seed, vegetable transplant plugs and fixation by legume cover crops) and exports in harvested crops (lettuce, broccoli) over eight years to calculate soil surface and soil system N mass balances for the Salinas Organic Cropping Systems study in Salinas, CA. Our objectives were to 1) quantify the long-term effects of compost, cover crop frequency and cover crop type on soil N, cover crop and vegetable crop N uptake, and yield, and 2) tabulate N balances to assess the effects of these factors on N export in harvested crops, soil N storage and potential N loss. Results show that across all systems only 13 to 23% of N inputs were exported in harvest. Annual compost applications increased soil N stocks but had little effect on vegetable N uptake or yield, increasing the cumulative soil system N balance surplus over eight years by 999 kg ha-1, relative to the system receiving organic fertilizers alone. Annually planted winter cover crops increased N availability, crop uptake and export; however, biological N fixation by legumes negated the positive effect of increased harvest exports on the balance surplus in the legume-rye cover cropped system. Over eight years, rye cover crops improved system performance and reduced the cumulative N surplus by 384 kg ha-1 relative to the legume-rye mixture by increasing N retention and availability without increasing N inputs. Reduced reliance on external compost inputs and increased use of annually planted non-legume cover crops can improve efficient N use and cropping system yield, consequently improving environmental performance.
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Affiliation(s)
- Kathryn E. White
- United States Department of Agriculture, Agricultural Research Service, Sustainable Agricultural Systems Laboratory, Beltsville Agricultural Research Center, Beltsville, Maryland, United States of America
- * E-mail:
| | - Eric B. Brennan
- United States Department of Agriculture, Agricultural Research Service, Salinas, California, United States of America
| | - Michel A. Cavigelli
- United States Department of Agriculture, Agricultural Research Service, Sustainable Agricultural Systems Laboratory, Beltsville Agricultural Research Center, Beltsville, Maryland, United States of America
| | - Richard F. Smith
- University of California Cooperative Extension, Salinas, California, United States of America
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5
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Daly AB, Jilling A, Bowles TM, Buchkowski RW, Frey SD, Kallenbach CM, Keiluweit M, Mooshammer M, Schimel JP, Grandy AS. A holistic framework integrating plant-microbe-mineral regulation of soil bioavailable nitrogen. BIOGEOCHEMISTRY 2021; 154:211-229. [PMID: 34759436 PMCID: PMC8570341 DOI: 10.1007/s10533-021-00793-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 04/06/2021] [Indexed: 06/01/2023]
Abstract
UNLABELLED Soil organic nitrogen (N) is a critical resource for plants and microbes, but the processes that govern its cycle are not well-described. To promote a holistic understanding of soil N dynamics, we need an integrated model that links soil organic matter (SOM) cycling to bioavailable N in both unmanaged and managed landscapes, including agroecosystems. We present a framework that unifies recent conceptual advances in our understanding of three critical steps in bioavailable N cycling: organic N (ON) depolymerization and solubilization; bioavailable N sorption and desorption on mineral surfaces; and microbial ON turnover including assimilation, mineralization, and the recycling of microbial products. Consideration of the balance between these processes provides insight into the sources, sinks, and flux rates of bioavailable N. By accounting for interactions among the biological, physical, and chemical controls over ON and its availability to plants and microbes, our conceptual model unifies complex mechanisms of ON transformation in a concrete conceptual framework that is amenable to experimental testing and translates into ideas for new management practices. This framework will allow researchers and practitioners to use common measurements of particulate organic matter (POM) and mineral-associated organic matter (MAOM) to design strategic organic N-cycle interventions that optimize ecosystem productivity and minimize environmental N loss. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10533-021-00793-9.
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Affiliation(s)
- Amanda B. Daly
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Road, Durham, NH 03824 USA
| | - Andrea Jilling
- Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK USA
| | - Timothy M. Bowles
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA USA
| | | | - Serita D. Frey
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Road, Durham, NH 03824 USA
| | | | - Marco Keiluweit
- School of Earth & Sustainability and Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA USA
| | - Maria Mooshammer
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA USA
| | - Joshua P. Schimel
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA USA
| | - A. Stuart Grandy
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Road, Durham, NH 03824 USA
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6
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Lazcano C, Zhu-Barker X, Decock C. Effects of Organic Fertilizers on the Soil Microorganisms Responsible for N 2O Emissions: A Review. Microorganisms 2021; 9:microorganisms9050983. [PMID: 34062833 PMCID: PMC8147359 DOI: 10.3390/microorganisms9050983] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/20/2021] [Accepted: 04/24/2021] [Indexed: 11/16/2022] Open
Abstract
The use of organic fertilizers constitutes a sustainable strategy to recycle nutrients, increase soil carbon (C) stocks and mitigate climate change. Yet, this depends largely on balance between soil C sequestration and the emissions of the potent greenhouse gas nitrous oxide (N2O). Organic fertilizers strongly influence the microbial processes leading to the release of N2O. The magnitude and pattern of N2O emissions are different from the emissions observed from inorganic fertilizers and difficult to predict, which hinders developing best management practices specific to organic fertilizers. Currently, we lack a comprehensive evaluation of the effects of OFs on the function and structure of the N cycling microbial communities. Focusing on animal manures, here we provide an overview of the effects of these organic fertilizers on the community structure and function of nitrifying and denitrifying microorganisms in upland soils. Unprocessed manure with high moisture, high available nitrogen (N) and C content can shift the structure of the microbial community, increasing the abundance and activity of nitrifying and denitrifying microorganisms. Processed manure, such as digestate, compost, vermicompost and biochar, can also stimulate nitrifying and denitrifying microorganisms, although the effects on the soil microbial community structure are different, and N2O emissions are comparatively lower than raw manure. We propose a framework of best management practices to minimize the negative environmental impacts of organic fertilizers and maximize their benefits in improving soil health and sustaining food production systems. Long-term application of composted manure and the buildup of soil C stocks may contribute to N retention as microbial or stabilized organic N in the soil while increasing the abundance of denitrifying microorganisms and thus reduce the emissions of N2O by favoring the completion of denitrification to produce dinitrogen gas. Future research using multi-omics approaches can be used to establish key biochemical pathways and microbial taxa responsible for N2O production under organic fertilization.
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Affiliation(s)
- Cristina Lazcano
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA 95616, USA;
- Correspondence:
| | - Xia Zhu-Barker
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA 95616, USA;
| | - Charlotte Decock
- Natural Resources Management and Environmental Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA;
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7
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Abalos D, De Deyn GB, Philippot L, Oram NJ, Oudová B, Pantelis I, Clark C, Fiorini A, Bru D, Mariscal‐Sancho I, Groenigen JW. Manipulating plant community composition to steer efficient N‐cycling in intensively managed grasslands. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13788] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Diego Abalos
- Soil Biology Group Wageningen University Wageningen The Netherlands
- Department of Agroecology Aarhus University Tjele Denmark
| | | | - Laurent Philippot
- Université Bourgogne Franche‐ComtéINRAAgroSup DijonAgroécologie Dijon France
| | - Natalie J. Oram
- Soil Biology Group Wageningen University Wageningen The Netherlands
| | - Barbora Oudová
- Soil Biology Group Wageningen University Wageningen The Netherlands
- School of Biological Sciences University of East Anglia Norwich UK
| | - Ioannis Pantelis
- Soil Biology Group Wageningen University Wageningen The Netherlands
| | - Callum Clark
- Soil Biology Group Wageningen University Wageningen The Netherlands
| | - Andrea Fiorini
- Department of Sustainable Crop Production Università Cattolica del Sacro Cuore Piacenza Italy
| | - David Bru
- Université Bourgogne Franche‐ComtéINRAAgroSup DijonAgroécologie Dijon France
| | - Ignacio Mariscal‐Sancho
- Departamento de Producción Agraria ETS Ingeniería Agronómica Alimentaria y de Biosistemas Universidad Politécnica de Madrid Madrid Spain
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8
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Wade J, Culman SW, Logan JAR, Poffenbarger H, Demyan MS, Grove JH, Mallarino AP, McGrath JM, Ruark M, West JR. Improved soil biological health increases corn grain yield in N fertilized systems across the Corn Belt. Sci Rep 2020; 10:3917. [PMID: 32127596 PMCID: PMC7054259 DOI: 10.1038/s41598-020-60987-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/04/2020] [Indexed: 12/02/2022] Open
Abstract
Nitrogenous fertilizers have nearly doubled global grain yields, but have also increased losses of reactive N to the environment. Current public investments to improve soil health seek to balance productivity and environmental considerations. However, data integrating soil biological health and crop N response to date is insufficient to reliably drive conservation policy and inform management. Here we used multilevel structural equation modeling and N fertilizer rate trials to show that biologically healthier soils produce greater corn yields per unit of fertilizer. We found the effect of soil biological health on corn yield was 18% the magnitude of N fertilization, Moreover, we found this effect was consistent for edaphic and climatic conditions representative of 52% of the rainfed acreage in the Corn Belt (as determined using technological extrapolation domains). While N fertilization also plays a role in building or maintaining soil biological health, soil biological health metrics offer limited a priori information on a site's responsiveness to N fertilizer applications. Thus, increases in soil biological health can increase corn yields for a given unit of N fertilizer, but cannot completely replace mineral N fertilization in these systems. Our results illustrate the potential for gains in productivity through investment in soil biological health, independent of increases in mineral N fertilizer use.
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Affiliation(s)
- Jordon Wade
- School of Environment & Natural Resources, The Ohio State University, Ohio, USA.
- Department of Crop Sciences, University of Illinois, Urbana-Champaign, Illinois, USA.
| | - Steve W Culman
- School of Environment & Natural Resources, The Ohio State University, Ohio, USA
| | - Jessica A R Logan
- College of Education and Human Ecology, The Ohio State University, Ohio, USA
| | - Hanna Poffenbarger
- Department of Plant and Soil Sciences, University of Kentucky, Kentucky, USA
| | - M Scott Demyan
- School of Environment & Natural Resources, The Ohio State University, Ohio, USA
| | - John H Grove
- Department of Plant and Soil Sciences, University of Kentucky, Kentucky, USA
| | | | - Joshua M McGrath
- Department of Plant and Soil Sciences, University of Kentucky, Kentucky, USA
| | - Matthew Ruark
- Department of Soil Science, University of Wisconsin - Madison, Wisconsin, USA
| | - Jaimie R West
- Department of Soil Science, University of Wisconsin - Madison, Wisconsin, USA
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9
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Schmidt JE, Kent AD, Brisson VL, Gaudin ACM. Agricultural management and plant selection interactively affect rhizosphere microbial community structure and nitrogen cycling. MICROBIOME 2019; 7:146. [PMID: 31699148 PMCID: PMC6839119 DOI: 10.1186/s40168-019-0756-9] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/02/2019] [Indexed: 05/11/2023]
Abstract
BACKGROUND Rhizosphere microbial communities are key regulators of plant performance, yet few studies have assessed the impact of different management approaches on the rhizosphere microbiomes of major crops. Rhizosphere microbial communities are shaped by interactions between agricultural management and host selection processes, but studies often consider these factors individually rather than in combination. We tested the impacts of management (M) and rhizosphere effects (R) on microbial community structure and co-occurrence networks of maize roots collected from long-term conventionally and organically managed maize-tomato agroecosystems. We also explored the interaction between these factors (M × R) and how it impacts rhizosphere microbial diversity and composition, differential abundance, indicator taxa, co-occurrence network structure, and microbial nitrogen-cycling processes. RESULTS Host selection processes moderate the influence of agricultural management on rhizosphere microbial communities, although bacteria and fungi respond differently to plant selection and agricultural management. We found that plants recruit management-system-specific taxa and shift N-cycling pathways in the rhizosphere, distinguishing this soil compartment from bulk soil. Rhizosphere microbiomes from conventional and organic systems were more similar in diversity and network structure than communities from their respective bulk soils, and community composition was affected by both M and R effects. In contrast, fungal community composition was affected only by management, and network structure only by plant selection. Quantification of six nitrogen-cycling genes (nifH, amoA [bacterial and archaeal], nirK, nrfA, and nosZ) revealed that only nosZ abundance was affected by management and was higher in the organic system. CONCLUSIONS Plant selection interacts with conventional and organic management practices to shape rhizosphere microbial community composition, co-occurrence patterns, and at least one nitrogen-cycling process. Reframing research priorities to better understand adaptive plant-microbe feedbacks and include roots as a significant moderating influence of management outcomes could help guide plant-oriented strategies to improve productivity and agroecosystem sustainability.
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Affiliation(s)
- Jennifer E. Schmidt
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616 USA
| | - Angela D. Kent
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, N-215 Turner Hall, MC-047, 1102 S. Goodwin Avenue, Urbana, IL USA
| | - Vanessa L. Brisson
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 USA
- The DOE Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598 USA
| | - Amélie C. M. Gaudin
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616 USA
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10
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Organic versus Conventional Cropping Sustainability: A Comparative System Analysis. SUSTAINABILITY 2018. [DOI: 10.3390/su10010272] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We are at a pivotal time in human history, as the agricultural sector undergoes consolidation coupled with increasing energy costs in the context of declining resource availability. Although organic systems are often thought of as more sustainable than conventional operations, the lack of concise and widely accepted means to measure sustainability makes coming to an agreement on this issue quite challenging. However, an accurate assessment of sustainability can be reached by dissecting the scientific underpinnings of opposing production practices and crop output between cropping systems. The purpose of this review is to provide an in-depth and comprehensive evaluation of modern global production practices and economics of organic cropping systems, as well as assess the sustainability of organic production practices through the clarification of information and analysis of recent research. Additionally, this review addresses areas where improvements can be made to help meet the needs of future organic producers, including organic-focused breeding programs and necessity of coming to a unified global stance on plant breeding technologies. By identifying management strategies that utilize practices with long-term environmental and resource efficiencies, a concerted global effort could guide the adoption of organic agriculture as a sustainable food production system.
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11
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Bowles TM, Barrios-Masias FH, Carlisle EA, Cavagnaro TR, Jackson LE. Effects of arbuscular mycorrhizae on tomato yield, nutrient uptake, water relations, and soil carbon dynamics under deficit irrigation in field conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:1223-1234. [PMID: 27266519 DOI: 10.1016/j.scitotenv.2016.05.178] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/10/2016] [Accepted: 05/25/2016] [Indexed: 05/19/2023]
Abstract
Plant strategies to cope with future droughts may be enhanced by associations between roots and soil microorganisms, including arbuscular mycorrhizal (AM) fungi. But how AM fungi affect crop growth and yield, together with plant physiology and soil carbon (C) dynamics, under water stress in actual field conditions is not well understood. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant nonmycorrhizal tomato genotype rmc were grown in an organic farm with a deficit irrigation regime and control regime that replaced evapotranspiration. AM increased marketable tomato yields by ~25% in both irrigation regimes but did not affect shoot biomass. In both irrigation regimes, MYC+ plants had higher plant nitrogen (N) and phosphorus (P) concentrations (e.g. 5 and 24% higher N and P concentrations in leaves at fruit set, respectively), 8% higher stomatal conductance (gs), 7% higher photosynthetic rates (Pn), and greater fruit set. Stem water potential and leaf relative water content were similar in both genotypes within each irrigation regime. Three-fold higher rates of root sap exudation in detopped MYC+ plants suggest greater capacity for water uptake through osmotic driven flow, especially in the deficit irrigation regime in which root sap exudation in rmc was nearly absent. Soil with MYC+ plants also had slightly higher soil extractable organic C and microbial biomass C at anthesis but no changes in soil CO2 emissions, although the latter were 23% lower under deficit irrigation. This study provides novel, field-based evidence for how indigenous AM fungi increase crop yield and crop water use efficiency during a season-long deficit irrigation and thus play an important role in coping with increasingly limited water availability in the future.
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Affiliation(s)
- Timothy M Bowles
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA 95616, USA.
| | - Felipe H Barrios-Masias
- Department of Agriculture, Nutrition and Veterinary Sciences, University of Nevada, Reno, Reno, NV 89557, USA
| | - Eli A Carlisle
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA 95616, USA
| | - Timothy R Cavagnaro
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5065, Australia
| | - Louise E Jackson
- Department of Land, Air and Water Resources, University of California Davis, Davis, CA 95616, USA
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