Tag: soil diversity

Collaborative paper published on winter wheat, farming practices, and climate!

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The second paper from Tindall’s master’s work at Montana State University in the Menalled Lab has been accepted for publication! Tindall defended her master’s in August 2021, and has been working at a plant production company in Bozeman since then.

Ouverson, T., Boss, D., Eberly, J., Seipel, T.,  Menalled, F.D., Ishaq, S.L. 2022. Soil  bacterial community response to cover crops, cover crop termination, and predicted climate conditions in a dryland cropping system. Frontiers in Sustainable Food Systems.

Abstract

Soil microbial communities are integral to highly complex soil environments, responding to changes in aboveground plant biodiversity, influencing physical soil structure, driving nutrient cycling, and promoting both plant growth and disease suppression. Cover crops can improve soil health, but little is known about their effects on soil microbial community composition in semiarid cropping systems, which are rapidly becoming warmer and drier due to climate change. This study focused on a wheat-cover crop rotation near Havre, Montana that tested two cover crop mixtures (five species planted early season and seven species planted mid-season) with three different termination methods (chemical, grazed, or hayed and baled) against a fallow control under ambient or induced warmer/drier conditions. Soil samples from the 2018 and 2019 cover crop/fallow phases were collected for bacterial community 16S rRNA gene sequencing. The presence and composition of cover crops affected evenness and community composition. Bacterial communities in the 2018 ambient mid-season cover crops, warmer/drier mid-season cover crops, and ambient early season cover crops had greater richness and diversity than those in the warmer/drier early season cover crops. Soil microbial communities from mid-season cover crops were distinct from the early season cover crops and fallow. No treatments affected bacterial alpha or beta diversity in 2019, which could be attributed to high rainfall. Results indicate that cover crop mixtures including species tolerant to warmer and drier conditions can foster diverse soil bacterial communities compared to fallow soils.

Figure 1, showing a schematic of the fields and experimental design.

Related works from that research group include:

Collaborative paper accepted on winter wheat, weeds, and climate.

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The last paper to be generated from the large-scale, multi-year, collaborative research I participated in as a postdoc at Montana State University in the Menalled Lab in 2016 has finally been accepted for publication! At the time, I was working on the soil bacteria associated with winter wheat crops under different simulated climate change scenarios, and with added stressors like weed competition and different farming strategies. I was part of a large team of researchers looking at various aspects of agricultural stressors on long-term food production, including several agroecologists who led the development of this paper.

Weed communities in winter wheat: responses to cropping systems and predicted warmer and drier climate conditions.

Tim Seipel, Suzanne L. Ishaq, Christian Larson, Fabian D. Menalled. Sustainability 2022, 14(11), 6880; https://doi.org/10.3390/su14116880. Special Issue “Sustainable Weed Control in the Agroecosystems“

Abstract

Understanding the impact of biological and environmental stressors on cropping systems is essential to secure the long-term sustainability of agricultural production in the face of unprecedented climatic conditions. This study evaluated the effect of increased soil temperature and reduced moisture across three contrasting cropping systems: a no-till chemically managed system, a tilled organic system, and an organic system that used grazing to reduce tillage intensity. Results showed that while cropping system characteristics represent a major driver in structuring weed communities, the short-term impact of changes in temperature and moisture conditions appear to be more subtle. Weed community responses to temperature and moisture manipulations differed across variables: while biomass, species richness, and Simpson’s diversity estimates were not affected by temperature and moisture conditions, we observed a minor but significant shift in weed community composition. Higher weed biomass was recorded in the grazed/reduced-till organic system compared with the tilled-organic and no-till chemically managed systems. Weed communities in the two organic systems were more diverse than in the no-till conventional system, but an increased abundance in perennial species such as Cirsium arvense and Taraxacum officinale in the grazed/reduced-till organic system could hinder the adoption of integrated crop-livestock production tactics. Species composition of the no-till conventional weed communities showed low species richness and diversity, and was encompassed in the grazed/reduced-till organic communities. The weed communities of the no-till conventional and grazed/reduced-till organic systems were distinct from the tilled organic community, underscoring the effect that tillage has on the assembly of weed communities. Results highlight the importance of understanding the ecological mechanisms structuring weed communities, and integrating multiple tactics to reduce off-farm inputs while managing weeds.

The related works from that project include:

Similar work has been done by that group, including:

Introducing the Microbes and Social Equity Working Group: Considering the Microbial Components of Social, Environmental, and Health Justice

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The Microbes and Social Equity Working Group is delighted to make its published debut, with this collaboratively-written perspective piece introducing ourselves and our goals. You can read about us here.

This piece also debuts the special series we are curating in partnership with the scientific journal mSystems; “Special Series: Social Equity as a Means of Resolving Disparities in Microbial Exposure“. Over the next few months to a year, we will be adding additional peer-reviewed, cutting edge research, review, concept, and perspective pieces from researchers around the globe on a myriad of topics which center around social inequity and microbial exposures.

Ishaq, S.L., Parada, F.J., Wolf, P.G., Bonilla, C.Y., Carney, M.A., Benezra, A., Wissel, E., Friedman, M., DeAngelis, K.M., Robinson, J.M., Fahimipour, A.K., Manus, M.B., Grieneisen, L., Dietz, L.G., Pathak, A., Chauhan, A., Kuthyar, S., Stewart, J.D., Dasari, M.R., Nonnamaker, E., Choudoir, M., Horve, P.F., Zimmerman, N.B., Kozik, A.J., Darling, K.W., Romero-Olivares, A.L., Hariharan, J., Farmer, N., Maki, K.A., Collier, J.L., O’Doherty, K., Letourneau, J., Kline, J., Moses, P.L., Morar, N. 2021. Introducing the Microbes and Social Equity Working Group: Considering the Microbial Components of Social, Environmental, and Health Justice. mSystems 6:4.

Tindall’s first paper was accepted!

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I’m pleased to announce that master’s student Tindall Ouverson’s first manuscript was accepted for publication!

Photo of woman in front of mountains

Tindall is a Master’s of Science in the Department of Land Resources and Environmental Sciences at Montana State University. Her graduate advisers are Drs. Fabian Menalled and Tim Seipel. Her research focuses on the response of soil microbial communities to cropping systems and climate change in semiarid agriculture. 

I have been mentoring Tindall as a graduate committee member since she began in fall 2019, teaching her laboratory and analytical skills in microbial ecology, DNA sequencing, and bioinformatic analysis. We first met when she came to visit when I was working in Oregon, and since then have connected remotely. She has a flair for bioinformatics analysis, and a passion for sustainable agricultural development. She plans to defend her thesis in 2021, and then to further her career in sustainable agriculture in Montana.

Tindall Ouverson, Jed Eberly, Tim Seipel, Fabian D. Menalled, Suzanne L. Ishaq. 2021. Temporal soil bacterial community responses to cropping systems and crop identity in dryland agroecosystems of the Northern Great Plains.  Frontiers in Sustainable Food Systems.  Article. Invited submission to Plant Growth-Promoting Microorganisms for Sustainable Agricultural Production  special collection.

Abstract

Industrialized agriculture results in simplified landscapes where many of the regulatory ecosystem functions driven by soil biological and physicochemical characteristics have been hampered or replaced with intensive, synthetic inputs. To restore long-term agricultural sustainability and soil health, soil should function as both a resource and a complex ecosystem. In this study, we examined how cropping systems impact soil bacterial community diversity and composition, important indicators of soil ecosystem health. Soils from a representative cropping system in the semi-arid Northern Great Plains were collected in June and August of 2017 from the final phase of a five-year crop rotation managed either with chemical inputs and no-tillage, as a USDA-certified organic tillage system, or as a USDA-certified organic sheep grazing system with reduced tillage intensity. DNA was extracted and sequenced for bacteria community analysis via 16S rRNA gene sequencing. Bacterial richness and diversity decreased in all farming systems from June to August and was lowest in the chemical no-tillage system, while evenness increased over the sampling period. Crop species identity did not affect bacterial richness, diversity, or evenness. Conventional no-till, organic tilled, and organic grazed management systems resulted in dissimilar microbial communities. Overall, cropping systems and seasonal changes had a greater effect on microbial community structure and diversity than crop identity. Future research should assess how the rhizobiome responds to the specific phases of a crop rotation, as differences in bulk soil microbial communities by crop identity were not detectable.

Paper published on soil microbes, climate change, and agriculture!

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I’m pleased to announce that an article was published today on soil microbes, climate change, and agriculture! As local climates continue to shift, the dynamics of above- and below-ground associated bio-diversity will also shift, which will impact food production and the need for more sustainable practices. 

This publication is part of a series, from data collected from a long-term farming experiment in Bozeman, MT, led by researchers at Montana State University with whom I have published several times, including:

In this study, cropping system (such as organic or conventional), soil temperature, soil moisture, the diversity and biomass of weed communities, and treatment with Wheat streak mosaic virus were compared as related to the bacterial community in the soil associated with wheat plant roots.

This paper is open-access, which means anyone can read the full paper.

Dryland cropping systems, weed communities, and disease status modulate the effect of climate conditions on wheat soil bacterial communities.

Ishaq, S.L., Seipel, T., Yeoman, C.J., Menalled, F.D. 2020. mSphere DOI: 10.1128/mSphere.00340-20. Article.

Abstract

Little knowledge exists on how soil bacteria in agricultural settings are impacted by management practices and environmental conditions under current and predicted climate scenarios.  We assessed the impact of soil moisture, soil temperature, weed communities, and disease status on soil bacterial communities between three cropping systems: conventional no-till (CNT) utilizing synthetic pesticides and herbicides, 2) USDA-certified tilled organic (OT), and 3) USDA-certified organic with sheep grazing (OG).  Sampling date within the growing season, and associated soil temperature and moisture, exerted the greatest effect on bacterial communities, followed by cropping system, Wheat streak mosaic virus (WSMV) infection status, and weed community. Soil temperature was negatively correlated with bacterial richness and evenness, while soil moisture was positively correlated with bacterial richness and evenness.  Soil temperature and soil moisture independently altered soil bacterial community similarity between treatments.  Inoculation of wheat with WSMV altered the associated soil bacteria, and there were interactions between disease status and cropping system, sampling date, and climate conditions, indicating the effect of multiple stressors on bacterial communities in soil.  .  In May and July, cropping system altered the effect of climate change on the bacterial community composition in hotter, and hotter and drier conditions as compared to ambient conditions, in samples not treated with WSMV.  Overall, this study indicates that predicted climate modifications as well as biological stressors play a fundamental role in the impact of cropping systems on soil bacterial communities.

Wild blueberries on a bush.

My first funded proposal at UMaine!

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Now that I’m an assistant professor, a significant amount of my time is spent writing grant proposals to fund projects I’d like to do in the future.

Many large federal or foundational grants take up to a year from submission to funds distribution, and the success rate, especially for newly-established researches, can be quite low. It’s prudent to start writing well in advance of the due date, and to start small, with “pilot projects”.

To that end, I’m pleased to announce that Dr. Lily Calderwood and I just received word that the Wild Blueberry Commission of Maine is funding a pilot project of ours; “Exploration of Soil Microbiota in Wild Blueberry Soils“. We’ll be recruiting 1 – 2 UMaine students for summer/fall 2020 to participate in the research for their Capstone senior research projects.

Dr. Calderwood is an Extension Wild Blueberry Specialist, and Assistant Professor of Horticulture in the School of Food and Agriculture at UMaine. She and I developed this project when meeting for the first time, over coffee. We realized we’d both been at the University of Vermont doing our PhD’s concurrently, and in neighboring buildings! We got to chatting about my work in wheat soil microbial communities, and her work on blueberry production, and the untapped research potential between the two.

This pilot will generate some preliminary data to help us get a first look at the soil microbiota associated with blueberries, and in response to management practices and environmental conditions. From this seed funding, Lily and I hope to cultivate fruitful research projects for years to come!

Featured Image: Wild Maine Blueberries, Wikimedia

Paper published on effect of farming systems on soil bacteria!

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After several years of bouncing through internal and external review, I’m pleased to announce that the first microbes paper out of the Montana State University Fort Ellis project has been published in Geoderma! The Fort Ellis research has encompassed multiple labs, projects, and many personnel, as it was a large collaboration looking at the effect of different farming systems on biodiversity at the macro (plant), mini (insect), and micro (-be) levels. Spanning multiple years, this project has been a massive undertaking that I briefly participated in but anticipate getting four publications out of (two more are in preparation).

Winter wheat

I previously presented this work at the 2017 Ecological Society of America (ESA) conference (poster: Ishaq et al ESA 2017 poster). And this field soil was the “soil probiotic” that was used in the follow-up greenhouse trial that I ran which was also published this year.

Soil bacterial communities of wheat vary across the growing season and among dryland farming systems.

Ishaq, S.L., Seipel, T., Yeoman, C.J., Menalled, F.D. 2020. Geoderma 358:113989.

Abstract

Despite knowledge that management practices, seasonality, and plant phenology impact soil microbiota; farming system effects on soil microbiota are not often evaluated across the growing season.  We assessed the bacterial diversity in soil around wheat roots through the spring and summer of 2016 in winter wheat (Triticum aestivium L.) in Montana, USA, from three contrasting farming systems: a chemically-managed no-tillage system, and two USDA-certified organic systems in their fourth year, one including tillage and one where sheep grazing partially offsets tillage frequency. Bacterial richness (range 605 – 1174 OTUs) and evenness (range 0.80 – 0.92) peaked in early June and dropped by late July (range 92 – 1190, 0.62-0.92, respectively), but was not different by farming systems.  Organic tilled plots contained more putative nitrogen-fixing bacterial genera than the other two systems.  Bacterial community similarities were significantly altered by sampling date, minimum and maximum temperature at sampling, bacterial abundance at date of sampling, total weed richness, and coverage of Taraxacum officinale, Lamium ampleuxicaule, and Thlaspi arvense.  This study highlights that weed diversity, season, and farming management system all influence soil microbial communities. Local environmental conditions will strongly condition any practical applications aimed at improving soil diversity, especially in semi-arid regions where abiotic stress and seasonal variability in temperature and water availability drive primary production. Thus, it is critical to incorporate or address seasonality in soil sampling for microbial diversity.

A visit from Bozeman

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Last year, one of my former research groups at Montana State University was awarded a USDA NIFA Foundational program grant, and I am a sub-award PI on that grant.  We’ll be working together to investigate the effect of diversified farming systems – such as those that use cover crops, rotations, or integrate livestock grazing into field management – on crop production and soil bacterial communities: “Diversifying cropping systems through cover crops and targeted grazing: impacts on plant-microbe-insect interactions, yield and economic returns.”

The first soil samples were collected in Montana this summer, and I have been processing them for the past few weeks. I am using the opportunity to train a master’s student on microbiology and molecular genetics lab work. 

  • Montana field soil.
  • Prepped for DNA extraction.

Tindall Ouverson started this fall as a master’s student at MSU, working with Fabian Menalled and Tim Seipel in Bozeman, MT.  She’s an environmental and soil scientist, and this is her first time working with microbes.  She was here in Eugene for just a few days to learn everything needed for sequencing: DNA extraction, polymerase chain reaction, gel electrophoresis and visualization, DNA cleanup using magnetic beads, quantification, and pooling.  Despite not having experience in microbiology or molecular biology, Tindall showed a real aptitude and picked up the techniques faster than I expected!

  • Gel electrophoresis: using electricity to move DNA.
  • DNA is negatively-charged, it will move towards a positive cathode.
  • The speed of DNA is related to how large it is.
  • Once the DNA has moved through the gel, we can see it using UV light.
  • Each band represents a lot of DNA of a certain size, that all traveled at a certain pace through the gel.

Once the sequences are generated, I’ll be (remotely) training Tindall on DNA sequence analysis.  I’ll also be serving as one of her thesis committee members! Tindall will be the first of (hopefully) many cross-trained graduate students between myself and collaborators at MSU.

USDA AFRI NIFA Agricultural Production Systems grant awarded to Menalled et al.

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In 2016, I was a post-doc in the Menalled Lab, which studies plant and weed ecology in the context of agricultural production and sustainability.  There, I assessed soil bacterial communities under different farming management practices and climate scenarios.  I also helped to develop a grant proposal, which was just accepted by the USDA AFRI NIFA Agricultural Production Systems!  Leading this project is Dr. Fabian Menalled (as Principal Investigator, or PI), along with a number of other PIs; Dr. Amy Trowbridge, Dr. David Weaver, Dr. Tim Seipel, Dr. Maryse Bourgault, and Dr. Carl Yeoman, and collaborators Dr. Darrin Boss, Dr. Kate Fuller, Dr. Ylva Lekberg, and myself as a subaward PI.  I will again be providing microbial community analysis for this project, and collectively the project investigators will bring expertise in plant ecology, agronomy, economics, soil and plant chemistry, microbial ecology, agroecosystems, and more.

This research and extension project focuses on the needs of dryland agricultural stakeholders and it was designed in close collaboration with the NARC Advisory Board. While I was only able to attend one meeting, other team members regularly meet with Montana producers to discuss current issues and identify locally-sourced needs for agricultural research.  During this project, we will continue to meet with the NARC Advisory Board to share our results, evaluate implications, and better serve the producer community.

Diversifying cropping systems through cover crops and targeted grazing: impacts on plant-microbe-insect interactions, yield and economic returns.

Project summary

The semi-arid section of the Northern Great Plains is one of the
largest expanses of small grain agriculture and low-intensity livestock
production. However, extreme landscape simplification, excessive reliance on
off-farms inputs, and warmer and drier conditions hinder its agricultural
sustainability. This project evaluates the potential of diversifying this region
through the integration of cover crops and targeted grazing. We will complement
field and greenhouse studies to appraise the impact of system diversity,
temperature, and precipitation on key multi-trophic interactions, yields, and
economic outputs. Specifically, we will 1) Assess ecological drivers as well as
agronomic and economic consequences of integrating cover crops and livestock
grazing in semi-arid systems, 2) Evaluate how climate variability modify the
impacts of cover crops and livestock grazing on agricultural outputs. Specifically,
we will 2.1) Compare the effect of increased temperature and reduced moisture
on agronomic and economic performance of simplified and diversified systems,
2.2.) Assess the impact of climate and system diversity on associated biodiversity
(weeds, insect, and soil microbial communities) and above- and belowground
volatile organic (VOC) compound emissions, and 2.3) Evaluate how changes in
microbially induced VOCs influence multitrophic plant-insect interactions.

Objectives

  1. Assess key ecological drivers as well as agronomic and economic consequences of integrating cover crops and livestock grazing in semi-arid production systems
    • Compare the agronomic and economic performance of simplified and diversified systems
    • Assess the impact of cover crops and livestock grazing on the associated biodiversity (weeds, insects, and the soil microbiota)
  2. Evaluate how climate conditions modify the impacts of cover crops and livestock grazing on semi-arid production systems
    • Compare the effect of temperature and soil moisture on agronomic and economic performance of simplified and diversified systems
    • Assess the impact of climate and system diversity on associated biodiversity and above- and belowground volatile organic compound (VOC) emissions
    • Evaluate how changes in VOCs emissions influence important multitrophic interactions such as resistance to wheat stem sawfly and natural enemy host location cues
  3. Integrate the knowledge generated into an outreach program aimed at improving producers’ adoption of sustainable diversified crop-livestock systems

Field notes from my first ESA meeting

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IMG_20170808_083850[4637].jpg
From iDigBio
A couple of weeks ago, I attended my first Ecological Society of America meeting in Portland, which assembles a diverse community of researchers looking at system-wide processes.  It was an excellent learning experience for me, as scientific fields each have a particular set of tools to look at different problems and our collective perspectives can solve research problems in more creative ways.

In particular, it was intriguing to attend talks on the ecology of the human microbiome.  Due to the complexity of host-associated microbial communities, and the limitations of technology, the majority of studies to date have been somewhat observational.  We have mapped what is present in different animals, in different areas of the body, under different diet conditions, in different parts of the world, and in comparison between healthy and disease states.  But given the complexity of the day-to-day life of people, and ethics or technical difficulty of doing experimental studies in humans, many of the broader ecological questions have yet to be answered.

For example, how quickly do microbial communities assemble in humans?  When you disturb them or change something (like adding a medication or removing a food from your diet) how quickly does this manifest in the community structure and do those changes last? How does dysbiosis or dysfunction in the body specifically contribute to changes in the microbial community, or do seemingly harmless events trigger a change in the microbial community which then causes disease in humans? Some of the presentations I attended have begun teasing out these problems with a combination of observational in situ biological studies, in vitro laboratory studies, and in silico mathematical modeling.  The abstracts from all the meeting presentations can be found on the meeting website under Program.  I have also summarized several of the talks I went to on Give Me The Short Version.

One of my favorite parts was attending an open lunch with 500 Women Scientists, a recently-formed organization which promotes diversity and equality in science, and supports local activists to help change policy and preconceived notions about diversity in STEM.  The lunch meeting introduced the organization to the conference participants in attendance, asked us to voice our concerns or difficulties we had faced, encouraged us to reach out to others in our work network to seek advice and provide mentoring, and walked us through exercises designed to educate on how to build a more inclusive society.

500womensci.JPG
500 Women Scientists at ESA, August 2017

My poster presentation was on Wednesday, halfway through the meeting week, which gave me plenty of time to prepare.  You never know who might show up at your poster and what questions they’ll have.  In the past, I’ve always had a steady stream of people to chat with at my poster which has led to a number of scientific friendships and networking, and this year was no different.  The rather large (but detailed) poster file can be found here: Ishaq et al ESA 2017 poster .  Keep in mind that this is preliminary work, and many statistical tests have not yet been applied or verified.  I’ve been working to complete the analysis on the large study, which also encompasses a great deal of environmental data.  We hope to have manuscript drafted by this fall on this part of the project, and several more over the next year from the research team as this is part of a larger study; stay tuned!