Source: COLORADO STATE UNIVERSITY submitted to NRP
EXPLORING LINKAGES BETWEEN ABOVE AND BELOWGROUND DIVERSITY TO MAXIMIZE SOIL FUNCTIONAL CAPACITY IN DRYLAND AGRICULTURAL SYSTEMS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
1012941
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jul 1, 2017
Project End Date
Jun 30, 2022
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
COLORADO STATE UNIVERSITY
(N/A)
FORT COLLINS,CO 80523
Performing Department
Agricultural Biology
Non Technical Summary
Understanding belowground biodiversity for soil functioning and service delivery in agro-ecosystems is crucial for management of sustainable agriculture. Currently, we lack knowledge of how above- and below-ground communities and the multiple ecosystem processes that depend on them are linked particularly in dryland agro-ecosystems, and how these links may subsidize primary production and other ecosystem services as well as ecosystem multifunctionality. The overarching objective of this proposal is to test whether agro-ecosystem diversification can promote soil biodiversity and the delivery of beneficial ecosystem services in the drylands. In addition, the impacts of extreme climate events on the provision of ecosystem services by agro-ecosystems from different management practices varying in soil biodiversity will be assessed. This project will provide theoretical and applied framework on the impact of agro-ecosystem diversification on soil biodiversity and soil ecosystem service delivery in dryland agro-ecosystems, as well as novel insights of how we can maximize the provision of ecosystem services by soil biota through agricultural practices.
Animal Health Component
30%
Research Effort Categories
Basic
70%
Applied
30%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020110104030%
1360110106030%
1020110107020%
1020110310010%
9030199302010%
Goals / Objectives
The overarching goal of this project is to develop a theoretical and applied framework that will identify the impact of agricultural practices on the yield, biodiversity and sustainability of dryland agro-ecosystems by enhancing our understanding of soil microbial communities and their mediated functions. This will be achieved by the following complementary and inter-linked objectives:(1) Quantify the impact of land use/agricultural practices, in particular those increasing plant diversity, on soil communities, ecosystem functions and services.(2) Identify the interaction between soil aggregate size and soil microbial communities and determine the consequences of these interactions for multifunctionality of dryland agro-ecosystems.(3) Identify the legacy effects of change in belowground biodiversity by management practices on the provision of ecosystem services to provide resilience/restoration in novel environments.(4) Bring together the new data generated from this project with stakeholder's perspective to develop an empirical model that utilizes "multifunctionality indexes" as soil health indicators leading to the identification of innovative land management practices that maximize the delivery of multiple ecosystem services delivered by soil biota.(5) Implement engagement and feedback tools through workshops and field days to foster a collaborating and consultative methodology with early stage engagement, knowledge translation and implementation to growers and extension specialists.
Project Methods
To address our objectives, we will use sites from an ongoing "DRYLAND CROP COVER PROJECT" (http://drylandcovercrops.agsci.colostate.edu/swco/) that is being conducted for 2 years at multiple Colorado locations. This project includes sites from low to high above ground diversity, as well as field experiments where the diversity of agro-ecosystems is manipulated in time or space (e.g. through crop rotation, cover crops, or intercropping).Objective 1: We will sample soils from 0-10, 10-20, 20-30 and 30-40 cm depths from each plot. We have agreed with Co-PIs Dr Abdel Berrada that meta-data related to soil properties and plant yield will be shared. In addition, we perform on site analysis on several ecosystem properties including gas flux measurement. Soils samples will be subjected to size/aggregate separation using standard procedures. We will analyze each aggregate for multiple chemical, physical, and biological properties acting as surrogates of essential services in agroecosystems.Objective 2: We will assess below-ground diversity using high throughput sequencing (MiSeq Illumina)and advanced molecular biology approachs (qPCR, SIP)Objective 3: We will collect soil cores from field sites with low, medium and high soil biodiversity. These cores will be brought to the greenhouse and multiple functions will be assessed and related to soil biodiversity, soil characteristics and agricultural management. Following this, we will manipulate soil biodiversity by "microbial swap method" developed previous in the PIs laboratory to test whether changes in soil biodiversity influence multifunctionality and individual ecosystem services. We will test whether enhanced levels of aboveground diversity enhance soil ecosystem functions through positive effects on soil biodiversity. Finally, soil cores with different above and belowground diversity levels will be subjected to reduced precipitation using a common garden experiment. Using this system, we will test whether agro-ecosystem diversification promotes the resistance of ecosystem services to climate change.Objective 4: We will use advanced ecogenomics and statistical tools to assess the impact of above- and belowground diversity and management on both multifunctionality and individual ecosystem services. We will use different multifunctionality indexes, focused either on production, biodiversity and environmental sustainability. These different scenarios will be selected based upon discussions with stakeholders and project researchers. Together with stakeholders and policy makers we will develop a theoretical and applied framework using multifunctionality indexes to identify the impact of agricultural practices on the yield, biodiversity and sustainability of agroecosystems.Objective 5: The crucial aspect of our adoption pathway is our co-innovation with key stakeholders and end users, including growers, extension specialists, and advisors, who will provide samples and participate in identifying soil measures of relevance. Constant two-way communication between researchers and growers will be maintained from the beginning of the project via workshops, soil biology masterclass and field days. This will create the opportunity to receive feedback to permit the implementation of any changes, which will increase the practical impact of our research. We will also make short video clips for non-specialized audience (YouTube) describing innovative solutions and evidence-based approaches to promote farm productivity and food security. All research outcomes will be made publicly available through dissemination in technical articles, progress reports, conference presentations and high impact scientific publications. We will compile final report for all the end users and a policy report for communication to policy makers.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:We reached our target audience (farmers and extension specialists) through face-to-face meeting,telephone, and virtual discussions. We have communicated our results to the stakeholders, extension specialists, and researchers through presentations, virtual seminarsand field visits. Graduate students andpostdoctoral scientists, environmental professionals, and facultywere trained in the methods to analyze soil microbiome through classroom teaching and hands-on demonstration. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We demonstrate methods related to soil microbiome analysis at the "Summer Soil Institute" conducted by Colorado State University. During the course, training on various aspects of soil analysis was provided to a broad range of participants including graduate students, postdoctoral scientists, environmental professionals, faculty, and K-12 teachers. However, the Institute was cancelled due to the COVID-19 related closures. We have now developed videos of tools and techniques of microbiome science. We will refine these videos and post them online through our laboratory website. How have the results been disseminated to communities of interest?We reached our target audience (farmers and extension specialists) through face-to-face meeting and telephone discussions. We have communicated our results to the stakeholders, extension specialists, and researchers through presentations and field visits. Graduate students, postdoctoral scientists, environmental professionals, faculty, and K-12 teachers were trained in the methods to analyze soil microbiome through classroom teaching and hands on demonstration. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1: Our results showed that the microbial populations and activity in farms that incorporate cover crops were greater and more diverse than in soils farmed conventionally. Using next generation sequencing analysis we demonstrate a significant impact of farm management on the structure and function of soil microbiome. Our quantitative PCR based assessment of genes associated with soil C, N, and P cycling showed that cropping systems that have integrated cover crops are characterized by higher abundance of microbial guilds involved in nutrient cycling. Cover cropping systems have significantly higher multifunctionality indexes as compared to conventional farming systems. Soil multifunctionality indexes have been used as a proxy of soil health. We compared the microbiome networks of soil samples collected from fields that incorporate cover crops with conventionalfarms. The microbiome network was highly connected in the cover crop soils as compared to conventional. We also observed that cover crops increase microbial network complexity and the abundance of keystone beneficial taxa such as mycorrhizal fungi. Objective 2: Whole soil samples were analyzed to determine the effect of crop management on the structural diversity and functional potential of soil microbial communities in relation to indicators of soil C turnover. The soil samples were further fractioned into mega-aggregates (> 0.250mm), macro-aggregates (0.250-0.050mm); and micro-aggregates (< 0.050mm) using different modified sieving protocols. These aggregate fractions were analyzed to access relationships between soil C, microbial derived enzymes and soil bacterial community at the soil micro-environment scale (e.g. within different aggregate size fractions). A suite of advanced statistical approaches was used to link the microbial community composition with the functions related to soil C turnover. Different aggregates harbored different microbial communities reflecting the heterogeneity of soil structure. The soil microbial community regulated soil C storage and this regulation was strongest in the micro-aggregate where the greatest concentration of the stable form of organic C resides. Management practices such as residue retention and crop rotations promoted the establishment of specific microbial communities that had positive effects on C cycling and storage that was particularly important in the context of low-input agriculture. The impact of management on recalcitrant C (associated with micro-aggregates) was limited and mainly driven by associated micro-organisms. Objective 3: We conducted a greenhouse experiment to determine how the soil microbiome and crop plant interact during, and after, drought events in cover crops vs conventional farming systems. Soil cores with different above and belowground diversity levels were subjected to reduced precipitation using a common garden experiment. Using this system, we tested whether agroecosystem diversification promotes the resistance of ecosystem services to climate change. We hypothesized that enhanced levels of aboveground diversity in cover crop management enhance soil ecosystem functions through positive effects on soil biodiversity. Our preliminary results demonstrate that altered water frequency has a negative impact on soil microbial communities that directly modulate ecosystem multifunctionality. We also observed strong induction of the phytohormone abscisic acid (ABA) in response to drought. ABA plays major role in drought tolerance and can act as signal for selective recruitment of microbes that metabolize ABA. Interestingly, the ABA related selective recruitment was higher and faster in the rhizosphere of plants growing in the soils with higher aboveground diversity.We postulate that the initial soil microbiome modulates the root exudation mediated selective recruitment of the microbiome that provide drought resistance. We are now performing statistical and bioinformatics analysis to understand how and why these differences occur. Our ongoing research suggests that drought-induced shifts in root exudation metabolite composition correspond to changes in the functional potential of the rhizosphere microbiome. In our ongoing research, we aim to unravel the molecular basis of communication between plants and microbes under drought stress, creating a predictive framework for engineering the microbiome for enhanced drought resilience of the host plant. This knowledge may have practical applications for developing climate resilient crops. Objective 4: We identified the core microbiota (most abundant and ubiquitous in all soil samples) of wheat cropping systems in Colorado. These bacterial core taxa were mainly classified into Proteobacteria, Actinobacteria, and Nitrosomonas group. Fungal species from the genera Cladosporium, Periconia, Nigrospora and Bullera, as well as four unclassified at the genus level were identified as hub microorganisms in the core microbiome network. We then explored the ecological roles of the core microbiota in maintaining the connections between bacterial and fungal taxa. Metacommunity cooccurrence networks were established based on correlations for bacterial and fungal communities, respectively. To disentangle the linkages between the core microbiota and soil multifunctionality in agricultural ecosystems, we applied a random forest (RF) analysis to identify the main microbial contributors to the soil multifunctionality. We observed that the soil multifunctionality index were related to alpha-diversity and beta-diversity of both bacterial and fungal community. Furthermore, we quantified the contributions of core and noncore subcommunities to the soil multifunctionality index. In both bacterial and fungal community, the diversity of the core microbiota, rather than other noncore taxa, made a major contribution to predicting the soil multifunctionality index. These results were supported by a multivariate regression analysis collectively pointing to strong associations between the core microbiota and belowground multi- nutrient cycling. We used structural equation modeling to build a system-level understanding of the main drivers of soil multifunctionality We found that the relative abundance of Actinobacteria and alpha-Proteobacteria groups of bacteria and Sordariomucetes group of fungi had the most significant and direct effect on soil multifunctionality. Bacterial diversity also has a direct and independent influence of soil multifunctionality. These effects of microbiome variables were independent and were maintained even after considering the role of abiotic components on multifunctionality. Objective 5: We had multiple face-to-face meeting and telephone discussions with farmer groups and extension specialists. We have communicated our results to the stakeholders, extension specialists, and researchers at Corn College, Wrey, CO; Plant Pathology and Environmental Microbiology Seminars, Pennsylvania State University; Department of Horticultural Science, Colorado State University; Locus Agricultural Solutions, Solon, OH; Joint Genome Institute, Berkeley; Hawkesbury Institute for the Environment, Western Sydney University, Sydney, Australia; Entomological Society of America Annual Meeting; and Microbiome Movement.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Singh BK, P Trivedi, E. Egidi, CA Macdonald, M Delgado-Baquerizo (2020). Crop microbiome and sustainable agriculture. Nature Reviews Microbiology.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Trivedi P*, J Leach, S Tringe, BK Singh. 2020. Plantmicrobiome interactions: from community assembly to plant health. Nature Reviews Microbiology (https://www.nature.com/articles/s41579-020-0412-1)
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Qiu Z, J Wang, M Delgado-Baquerizo, P Trivedi et al. 2020. Plant microbiomes: Do different preservation approaches and primer sets alter our capacity to assess microbial diversity and community composition? Frontiers in Plant Science (https://www.frontiersin.org/articles/10.3389/fpls.2020.00993/full).
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Singh BK, H Liu, P Trivedi. 2020. Eco-holobiont: A new concept to identify drivers of host-associated microorganisms. Environmental Microbiology, 22, 564-567.
  • Type: Journal Articles Status: Accepted Year Published: 2021 Citation: Trivedi P, C Mattupalli, K Eversole, J Leach. 2020. Enabling sustainable agriculture through microbiome understanding and enhancement. New Phytologist (Tansley Review).
  • Type: Journal Articles Status: Accepted Year Published: 2021 Citation: Trivedi P, M Delgado Baquerizo, IC Anderson, F Maestre, BK Singh. Microbial taxonomical information explains a unique portion of the variance of soil carbon at regional and global scales. Nature Communication


Progress 10/01/18 to 09/30/19

Outputs
Target Audience: We reached our target audience (farmers and extension specialists) through face-to-face meeting and telephone discussions. We have communicated our results to the stakeholders, extension specialists, and researchers through presentations and field visits. Graduate students, postdoctoral scientists, environmental professionals, faculty, and K-12 teachers were trained in the methods to analyze soil microbiome through classroom teaching and hands on demonstration. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? The methods related to soil microbiome analysis were demonstrated at the "Summer Soil Institute" conducted by Colorado State University. During the course, training on various aspects of soil analysis was provided to a broad range of participants including graduate students, postdoctoral scientists, environmental professionals, faculty, and K-12 teachers. How have the results been disseminated to communities of interest?We had multiple face-to-face meeting and telephone discussions with farmer groups and extension specialists. We have communicated our results to the stakeholders, extension specialists, and researchers at "Agricultural Experiment Station meetings" at Fort Collins and Cortez; "Bioagricultural Sciences and Pest Management Departmental Seminar" and "CSU Ag Innovation Summit" at Fort Collins. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1:Our results showed that the microbial populations and activity in farms that incorporate cover crops were greater and more diverse than in soils farmed conventionally. Our results showed a clear separation between soil microbial communities of farms under cover crops and conventional management practices suggesting the significant impact of the farm management practices on the structure and function of soil microbiome. In addition, cropping systems that have integrated cover crops are characterized by higher abundance of microbial guilds involved in nutrient cycling and have significantly higher multifunctionality indexes used to measure soil health. We also observed that cover crops increase microbial network complexity and the abundance of keystone beneficial taxa such as mycorrhizal fungi.We are now investigating whether or not these observed differences translate into soil health outcomes and greater capacity to adapt to climate change. Objective 2:Among different sized aggregates the amount of labile C decreased with aggregate size whereas an opposite trend was observed for recalcitrant C. Overall the total C increased with decreasing aggregate size in all treatments. In mega- and macro-aggregates, the total C, total N, labile C, recalcitrant C and basal respiration of residue retained treatments were significantly higher than low residue and tillage treatments. We didn't observed any significant treatment effects in micro-aggregates in the amounts of total C, total N, labile C, and recalcitrant C. The labile nature of soil C for macro and mega-aggregates may, at least in part, explain the high influence of agricultural management on the total soil C in these types of aggregates. Contrary to this, the higher amount of recalcitrant C in micro-aggregates compared to macro- and mega-aggregates may provide a higher level of resistance to human management than the total soil C in this type of aggregates, as supported by the lower influence of agricultural management on soil C for micro-aggregates. Plant material enters the large aggregates after harvest mainly as labile forms of C and is linked to nutrient cycling and productivity, thus explaining the differences between different residue management practices. On the other hand, the deposition and retention of recalcitrant C in micro-aggregates that is potentially protected from microbial attack is more likely to explain stored C. We used the most comprehensive next generation sequencing techniques to determine the bacterial community composition in different aggregate fractions. Surprisingly our analysis showed an incredible diversity of soil bacteria associated with different aggregate fractions in our samples. We found that distinct aggregate size classes support distinct microbial habitats which support the development of different microbial communities. The dominance of slow growing "oligotrophs" in micro-aggregates results in lower microbial activity and hence more stable, recalcitrant, soil C. Microbial community in mega- and macro-aggregates were dominated by fast growing "copiotrophs" which, though their higher activity rates, release nutrients for plant growth. Overall we observed that residue retention has a more pronounced effect on the microbial community and their associated functions as compared to other management practices such as tillage or crop rotations and these differences are only applicable to mega and macro-aggregates. This result implies that quantity of residue may also be an important driver of microbial community as well as its quality (i.e. C:N ratio that might be the result of different crop sequences in different treatments). Faster turnover of crop inputs in the mega- and macro-aggregates due to the higher activity of "copiotrophs" in the residue retention treatments may result in greater availability of nutrients required for plant growth (C, N, and P). Objective 3:Cover crop systems harbor greater microbial diversity and abundances as compared to conventional systems. However, all previous studies simply looked at species diversity, and none of them have elucidated the role of soil microbes in providing and maintaining ecosystem multifunctionality in stress conditions. We have set up a greenhouse experiment to determine how the soil microbiome and crop plant interact during, and after, drought events in cover crops vs conventional farming systems. By understanding these interactions, we seek to identify the factors (microbial species/functions) within soil that predict how crops will respond to drought. Soil cores with different above and belowground diversity levels were subjected to reduced precipitation using a common garden experiment. Using this system, we are testing whether agroecosystem diversification promotes the resistance of ecosystem services to climate change. Additionally, we are testing whether enhanced levels of aboveground diversity in cover crop management enhance soil ecosystem functions through positive effects on soil biodiversity. Our preliminary results suggest that soils with higher belowground diversity provide buffer against various climate change drivers (including drought) by maintaining ecosystem multifunctionality. Our results demonstrate that altered water frequency has a negative impact on soil microbial communities that directly modulate ecosystem multifunctionality. Understanding the role of diversity (both above and belowground) on the functioning of agroecosystems and crop yield response to environmental stresses may help design "smart cropping systems" able to maintain provisioning and regulating ecosystem services under abnormal weather scenarios. However, to understand these processes we have to resolve the enigma of genomic and functional relationships influencing ecosystem multifunctionality and its impact on agroecosystem resilience and restoration in novel environmental conditions. Objective 4:Farmers need improved tools for monitoring the health of their soils, and research-based practical information to help them optimize soil health and develop the best suite of soil management practices for their particular operations. Current monitoring of soil health and quality typically involves time-consuming and relatively insensitive chemical and physical analyses. These largely bypass the activity of soil organisms and do not deliver a complete overview of soil health. We are using results from meta-genomic and spatial studies on microbial communities and community-level molecular characteristics to develop 'biomarker' indicators of ecosystem processes for monitoring and managing soil health under global change. We are using machine learning tools such as random forest classifier trained on bacterial data to indicate soil functions related to soil health. Our results indicate that soil microbial community is a significant predictor of the soil carbon turnover in dryland agroecosystems. Next step is to usemolecular approaches with the traditional soil chemical/physical/biological indicators to develop next generation soil quality indexes that provide early indications of improvement in soil health in relation to management practices such as cover crops. Objective 5:We had multiple face-to-face meeting and telephone discussions with farmer groups and extension specialists. We have communicated our results to the stakeholders, extension specialists, and researchers at "Agricultural Experiment Station meetings" at Fort Collins and Cortez; "Bioagricultural Sciences and Pest Management Departmental Seminar" and "CSU Ag Innovation Summit" at Fort Collins.

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Liking microbiome to earth ecosystem models: from genes to ecosystem (Invited)
  • Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Plant-associated microbiome
  • Type: Journal Articles Status: Submitted Year Published: 2020 Citation: Bacterial taxa predict soil carbon at global scales


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:We reached our target audience (farmers and extension specialists) through face-to-face meeting and telephone discussions. We have communicated our results to the stakeholders, extension specialists, and researchers through presentations and field visits.Graduate students, postdoctoral scientists, environmental professionals, faculty, and K-12 teachers were trained in the methods to analyze soil microbiome through classroom teaching and hands on demonstration. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The methods related to soil microbiome analysis were demonstrated at the "Summer Soil Institute" conducted by Colorado State University. During the course, training on various aspects of soil analysis was provided to a broad range of participants including graduate students, postdoctoral scientists, environmental professionals, faculty, and K-12 teachers. How have the results been disseminated to communities of interest?We had multiple face-to-face meeting and telephone discussions with farmer groups and extension specialists. We have communicated our results to the stakeholders, extension specialists, and researchers at "Eastern Colorado Crop Production Conference" at Fort Morgan; "Governors forum on Colorado Agriculture" at Denver; "Bioagricultural Sciences and Pest Management Departmental Seminar" and "CSU Ag Innovation Summit" at Fort Collins. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? An improved knowledge of the interactions between soil management practices and microbial communities in facilitating soil organic matter (SOM) decomposition and soil carbon (C) turnover is increasingly recognized as key to improve farm productivity and sustainability. However, significant gaps remain in our current understanding of how soil microbial communities respond to the complex interactions of biotic and abiotic site factors and how the shifts in soil microbial communities are linked to alterations in their functioning, such as in mediating SOM dynamics. Our preliminary results demonstrate that agronomic practices such as cover crops allow build-up of beneficial microbial communities that increase soil SOC retention and nutrient turnover. Benefits arising from these practices include increased biodiversity, nutrient cycling, and soil C storage that brings stability and health to soils thus maintaining productivity and quality of the industry at the farm gate while maximizing returns to growers. These findings also include environmental and social outcomes as great soil C accumulation in arable lands increase sustainable crop production and improve national economic and environmental sustainability. Objective 1: Soils samples were collected from Dryland Crop Cover Trials at South Western Colorado Research center, Yellow Jacket. Soil samples were processed and were submitted for total C, N, P analysis. We also analyzed soil samples for enzymatic activities (a-Glucosidase; N-acetyl-b-D-glucosaminidase; and b-D-celluliosidase) and soil respiration (using MicroResp analysis). Soil DNA was extracted and samples were analyzed through next generation sequencing analysis (for bacteria and fungi). qPCR analysis for various bacterial/fungal groups was performed. Our results showed changes in microbial activity (soil enzymes and respiration) and community structure in response to cover crop. Cover crop trails have significantly higher microbial activities as compared to fallow. Our results further showed significant differences in the microbial community composition and functions under cover crop trials as compared to control. The microbial species that are responsible for the differences were correlated with the various soil functions. Also, the number of bacteria belonging to Proteobacteria especially Pseudomonas were higher in cover crops. The structure of the bacterial community was markedly different between cover crops and control as shown by Principal Component Analysis (PCA)where a clear separation was observed between treatments. Similarly, we observed a clear separation of the fungal community between cover crops and control samples. In accordance with our hypothesis, community structure (b-diversity) for bacteria and fungi was significantly impacted. The relative abundance of bacterial groups such as Acidobacteria, Actinobacteria, Bacteroidetes and d-proteobacteria was higher in controltreatments. On the other hand, the relative abundance of a, b, and g Proteobacteria was higher in the cover crops. The relative abundance of species belonging to Basidiomycota were higher in cover crop treatments. Objective 2: We have optimized methods to separate soil samples into different sized aggregates. Collected soil samples were fractioned into three different sized aggregates: large mega- (>250 μm), macro (250-50 μm), and micro-aggregates (<50 μm). These samples were analyzed for soil nutrients (N, P, K); enzymes; and substrate induced respiration (by Microresp analysis). DNA from the samples was extracted and submitted for next-generation sequencing analysis. Our results showed that different sized aggregates harbored different microbial communities reflecting the heterogeneity of soil structure. Soil microbial communities regulated soil C storage and this regulation was strongest in the micro-aggregate fractions where the greatest concentration of stable organic C resides. Management practices such as residue retention and crop rotations promoted the establishment of specific microbial communities that had positive effects on labile C cycling (associated with mega- and macro-aggregates) that was particularly important in the context of low-input agriculture. The impact of management on recalcitrant C (associated with micro-aggregates) was limited and mainly driven by associated microorganisms. Global meta-analysis provided an indication that measures of microbial abundance may serve as indicators of changing soil health before an actual decline in physico-chemical properties can be detected. Objective 3 and 4: These objectives will depend on the results of 3 years of results from objective 1 and 2. Therefore these have been planned for 2020. Objective 5: We have communicated with the farmers and extension specialists during "Eastern Colorado Crop Production Conference 2018" at Fort Morgan. In addition, we have communicated our results to the stakeholders through face to face conversations and field trips multiple time during 2018.

Publications

  • Type: Book Chapters Status: Published Year Published: 2018 Citation: Trivedi P, Wallenstein MD, Delgado-Baquerizo M, Singh BK. 2018. Microbial Modulators and Mechanisms of Soil Carbon Storage. In Singh BK (ed.) Soil Carbon Storage: Modulators, Modelling. Academic Press 73-155
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Presentation at "International Conference on Microbiome Research", November 2018, Pune India


Progress 07/01/17 to 09/30/17

Outputs
Target Audience:Face-to-face meetings with extension specialists and farmer groups during Eastern Colorado Crop production conference. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?We had face-to-face meeting and telephone discussions with farmer groups and extension specialists. We have communicated our results to the stakeholders at "Soil health workshop" at Dover Creek and "Eastern Colorado Crop Production Conference" at Fort Morgan. A YouTube video of the presentation is available at: https://www.youtube.com/watch?v=gYlvGbUEzAw&t=24s What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? An improved knowledge of the interactions between soil management practices and microbial communities in facilitating soil organic matter (SOM) decomposition and soil carbon (C) turnover is increasingly recognized as key to improve farm productivity and sustainability. However, significant gaps remain in our current understanding of how soil microbial communities respond to the complex interactions of biotic and abiotic site factors and how the shifts in soil microbial communities are linked to alterations in their functioning, such as in mediating SOM dynamics. Our preliminary results demonstrate that agronomic practices such as cover crops allow build-up of beneficial microbial communities that increase soil SOC retention and nutrient turnover. Benefits arising from these practices include increased biodiversity, nutrient cycling, and soil C storage that brings stability and health to soils thus maintaining productivity and quality of the industry at the farm gate while maximizing returns to growers. These findings also include environmental and social outcomes as great soil C accumulation in arable lands increase sustainable crop production and improve national economic and environmental sustainability. Objective 1: Soils samples were collected from Dryland Crop Cover Trials atSouth Western Colorado Research center, Yellow Jacket. Soil samples were processed and samples have been submitted for total C, N, P analysis. We also analysed soil samples for enzymatic activities (a-Glucosidase;N-acetyl-b-D-glucosaminidase; andb-D-celluliosidase)and soil respiration (using MicroResp analysis). Soil DNA was extracted and samples have been submitted for next generation sequencing analysis (for bacteria and fungi; results expected Feb 2018). qPCR analysis for various bacterial/fungal groups has been completed. Our preliminary results show changes in microbial activity (soil enzymes and respiration) and community structurein response to cover crop. Cover crop trails have significantly higher microbial activities as compared to fallow. Also, the number of bacteria belonging to Proteobacteria especially Pseudomonas were higher in cover crops. As we are still awaiting results from next generation sequencing analysis that will allow us to correlate microbial community composition with soil processes. Objective 2: We have optimized methods to separate soil samples into different sized aggregates. Collected soil samples have been fractioned into three different sized aggregates: large mega- (>250 µm), macro (250-50 µm), and micro-aggregates (<50 µm). These samples are now been analyzed for soil nutrients (N, P, K); enzymes; and substrate induced respiration (by Microresp analysis). DNA from the samples has been extracted and submitted for next-generation sequencing analysis. Objective 3 and 4: These objectives will depend on the results of 3 years of results from objective 1 and 2. Therefore these have been planned for 2019. Objective 5: We have communicated with the farmers and extension specialists during "Soil health workshop" at Dover Creek and and "Eastern Colorado Crop Production Conference" at Fort Morgan.

Publications

  • Type: Book Chapters Status: Awaiting Publication Year Published: 2018 Citation: Trivedi P, Wallenstein MD, Delgado-Baquerizo M, Singh BK. Microbial modulators and mechanisms of soil carbon storage. In Singh BK (ed.) Soil Carbon Storage: Modulators, Mechanisms, Modelling. Academic Press. 254pp.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Leach JE, Triplett LR, Argueso CT, Trivedi P. 2017. Communication in the Phytobiome. Cell. 4, 587-596.