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Research Projects

Environmental Conservation

Forest conservation and management is already complex in New England.  Changes in temperature, precipitation, winter conditions and the timing of seasons have already been documented, and further changes are expected well into the future (Horton et al. 2014). Changes in forest conditions and the geographic distribution of forest types are likely to threaten some ecosystems more than others. Areal coverage of boreal forest and Northern hardwood forests are projected to decline based on model projections (Janowiak et al. 2018). This would affect those species of plants, animals, fungi and other organisms that depend on these ecosystems (Janowiak et al. 2018).
Ecosystems within forested environments, such as streams and wetlands, are also likely to undergo changes that will make it difficult to support viable populations of fish and wildlife and maintain forest biodiversity. For example, as air temperatures rise, corresponding increases in water temperature will further stress cold-water streams. As a result, cold-water stream habitats may disappear or become smaller and more fragmented (Preston 2006, Manomet Center 2013).
Landowners, foresters, conservation organizations, and municipal officials (forest decision- makers) need research-based information on potential impacts on forests and spatially explicit information to guide adaptation strategies and actions. Active conservation measures are necessary to: limit stream warming, identify and conserve potential cold-water refugia, strategically target land protection for refugia for threatened forest types, and ensure terrestrial and aquatic connectivity to maintain viable populations of species dependent on these threatened forest ecosystems. To increase resistance and resiliency to climate change, forest management practices will need to change to ensure species and structural diversity, and adjust to emerging threats, such as invasive species, pests and diseases. 

 Invasive plants are species introduced from another region (non-native) that have established self-sustaining populations and are spreading, often with substantial negative consequences.  Invasive plants have numerous detrimental effects on forest ecosystems.  Several forest understory invasive plants, such as oriental bittersweet, autumn olive, and honeysuckle outcompete or reduce growth of native vegetation. For example, glossy buckthorn grows in dense thickets that shade out native tree saplings and reduce their overall survival by up to 90%. Invasive plants also threaten forest regeneration by altering soil chemistry. For example, garlic mustard releases allelopathic chemicals that kill soil mycorrhizae and inhibit the establishment of native tree seedlings.  As a result of their vigorous growth, invasive plants are often able to dominate ecosystems following disturbance and impede forest succession.

Department of Project: Department of Biology

Many bee pollinators are in decline, and exposure to diseases has been implicated as one of the potential causes. In my lab, we have already established that pollen from one domesticated sunflower source dramatically reduces Crithidia infection loads in the common eastern bumble bees in the laboratory, and that consumption of this pollen improves performance of healthy and infected bee microcolonies. We will expand this work by growing many sunflower cultivars and related taxa, collecting pollen, and repeating laboratory assays to establish how widespread this medicinal trait is across sunflower-related taxa.

Forests are the natural vegetative cover for most of New England. In many parts of our region, the forests have been clearedtwice over the last 150 years, yet today they continue to dominate the landscape. Our forests have also faced threats, such asthe introduced chestnut blight, which removed the American chestnut (Castanea dentata), a once dominant tree species, fromthe landscape. Despite this and other losses, we continue to enjoy the many essential benefits forests provide to our daily lives,such as clean water, climate change mitigation, wildlife habitat, scenic landscapes, recreational opportunities, and forest products. In other words, our forests are inherently resilient. However, we are now facing an uncertain future, in which our forests will encounter many, often interacting, stressors, of particular note are forest conversion and parcellization (Stein et al. 2005; Olofson et. al. 2016); invasive insects (Hicke et. al.2012, Lovett et. al. 2016), and climate change (Franklin et. al. 2016, Janowiak et. al. 2018). Though our forests have shown themselves to be resilient, they also have characteristics that make them vulnerable to these stressors to varying degrees (e.g.,aging forest landowner population, simplified forest structure, and uniform composition). While there is uncertainty as to how our forests will react to these stressors, we can be confident that our forests will change. Understanding the ways in which these stressors will change our forests and developing strategies to address them is critical to maintaining the essential forest services on which we rely.

 

Department of Project: Stockbridge School of Agriculture

Increasing environmental stresses make crops ever more succeptible to the impact of plant viruses. Plant viruses affect plant functioning and, specifically, the root system. For example, virus infected cover crops may hamper root growth and activity. This may influence the effect of cover crops on the cycling of carbon and other nutrients in soils. Consequently, virus infections may undermine the beneficial use of cover crops to improve soil health, with unclear consequences for soil carbon storage, greenhouse gas emissions, and nutrient status. This project therefore tests how plant virus infection influences the impact of cover crops on soil carbon and nutrient cycling.

A pressing problem for forest managers and society as a whole is the need to mitigate rapid environmental changes affecting allof life on earth. Third to only to habitat destruction and direct exploitation, biological invasions are a leading cause of extinctionand loss of biodiversity in forest ecosystems and around the world (Dirzo and Raven 2003). One poorly understood aspect ofbiological invasions is that the introduction of non-native organisms to areas outside their home range leads to novel ecologicalinteractions among species that have not historically co-existed. These new interactions raise key theoretical questions, suchas: How do species adapt to new environments as they expand their range? Can novel species interactions alter longstandinginteractions between native species? Do native species re-assemble into new food-webs with novel suites of species afterinvasion? We will address these questions in terms of invasive plants and their effects on native species of New England'sforest ecosystems.

This study will provide important information on long-term trends in water demand and supply, aid in the formulation of water policies for water resource development, and offer information to help protect surface and groundwater supplies. This project will also target areas with the best potential for surface augmentation of water supplies based on the relative benefits and costs of water supply augmentation (through spatially explicit policies for runoff mitigation and groundwater recharge). This project will evaluate water resources within a watershed ecosystem framework, and thereby will consider multiple supplies and uses of water resources. This study will address three areas of special interest to the region, namely:
• Water management in the context of forest loss and rapid development and conflict for water supply;
• Improvements in the assessment of water availability, incorporating technological, institutional, cultural and economic factors that   influence water use and water availability and;
• Improved methods of characterizing and quantifying components of the water cycle in forested watersheds.

Our focus is on the essential pollination services provided by bees on cranberry, the major crop in the region, as well as the bee community in southeastern Massachusetts. Bumble bees, the most common and efficient pollinators of cranberry are undergoing rapid decline. Thus, our focus is surveying and curating collections of bees, education, and research directed at the health of bumble bees; regarding the latter, we will quantify the major pathogens affecting bumble bee health and impacts of grower practices, particularly systemic sprays prior to bloom (contaminating pollen and nectar) and fungicides sprayed at bloom.

This study will investigate how the estimated density of a forest ecosystem bioindicator species, the red backed salamander (P. cinereus)  is influenced by the design of a commonly applied sampling protocol. The project will provide important insights into the utility of artificial cover board surveys as a method for estimating salamander density for use as an indicator of forest ecosystem condition.

There is widespread interest in greening municipalities and increasing urban tree canopy cover, largely through local community-based tree planting initiatives. It is generally estimated that newly-installed (i.e. planted) trees require at least 3 or more years before establishment, when they resume pre-transplant growth rates. Most trees installed in the urban environment are dug from the nursery field with a spade, and wrapped in burlap and a metal basket ('balled and burlap' or 'B&B'). There is interest, however, by shade tree committee members and professional urban foresters alike, in planting trees grown using other easier-to-plant systems, including a variety of container-grown (CG, IGF) and bare-root (BR) tree production methods. Trees grown from these production systems, however, must have the potential to grow long-term and reach maturity to offer the numerous values associated with urban trees that include a variety of aesthetic, social, and environmental benefits.This may be a challenge, since urban environments often present very difficult growing conditions that habitually thwart tree growth and survival. Though advances in understanding have been made, empirical data to describe the survival and growth of such trees remains limited, with the preponderance of research considering trees growing in agricultural plots, rather than in urban settings. Since budget constraints are routinely identified as a key limiting factor relative to urban forest management practices, there is also a need for further information concerning the longer term costs associated with planting and maintaining urban trees. Collecting growth and maintenance cost data on established urban oak specimens in Amherst, MA, produced using various nursery systems will 1) add to the overall base of  knowledge concerning urban tree growth and survival 2) enable the quantification and further understanding of the relationship of urban tree growth/survival and nursery production system 3) Enable the quantification and further understanding of the long-term costs associated with planting and maintaining urban trees. The long-term goal of this work is to gather local, empirical data that will help urban forest practitioners consider the appropriate (i.e. most cost-effective, best-performing) nursery production system, when selecting trees for urban planting in Massachusetts communities.

The overarching goal of this project is to evaluate the potential for global change to affect marine ecosystems within the GOM.We will use a multi-pronged approach, investigating key marine fisheries and aquaculture species of economic importance. Wefirst focus on quantifying the current supply of larvae, a critical life stage for fisheries species, by developing a foundationalsampling framework using traditional taxonomic approaches. Second, we propose to use molecular techniques with larvae andeggs that are difficult to identify using taxonomy. Third, we will conduct focused laboratory experiments to investigate the impactof climate variables on larval performance. Fourth, we will engage directly with fisheries stakeholders to understand theconstraints and opportunities of future changes to species, or the timing and location of the fisheries that are targeting them.This project therefore has four major objectives:

1. Quantify larval supply of key fisheries species and evaluate match mismatch

2. Metabarcoding for fisheries species detection

3. Identify effects of climate on early life stages of key fisheries and aquaculture species

4. Stakeholder engagement to understand sensitivity and resiliency to climate change and the perspective of industry

Department of Project: Stockbridge School of Agriculture

Through this research project a variety of ornamental plants will be grown to assess how production practices can be improved through a series of experiments examining irrigation methods and volume, fertilizer quantity, substrate additives, and substrate components. Plant water needs will be assessed to understand how much irrigation is needed to produce good quality plants. This will provide growers with ways of improving irrigation applications by grouping plants by water needs and reducing irrigation applications when possible. Plant fertilizer needs will be assessed in a similar manner. By reducing fertilizer applications the amount of nutrients in the nursery or greenhouse runoff will be reduced lessening the environmental impact. Substrate components and additives will be assessed to further the body of knowledge on their impact on production with an emphasis on their impact on water applications, retention, and leaching and fertilizer retention and uptake.

Energy

The expansive growth of solar photovoltaics (PV) in Massachusetts has helped make the state a leader in renewable energy production, but there have been public concerns regarding the development of agricultural lands for solar PV electricity production. In response to these concerns, the Massachusetts Department of Energy Resources (DOER) included provisions in the new state solar energy program which limit conventional ground-mounted solar arrays on farmland, while encouraging innovative "dual-use" technology. Under the new Solar Massachusetts Renewable Target (SMART) program, there is a significant financial incentive for dual-use systems which limit shading and obstructions, and require continued agricultural production on the land below and around solar arrays.

Department of Project: Department of Biology

Current agricultural practices on available arable land will not meet the nutritional needs of a population that will reach nine billion people by the middle of this century (Ray et al. 2013). In parallel, climate change will increase extreme weather events, including drought (Dai, 2011, Trenberth et al., 2014), and continued urbanization of farmland is eliminating arable land (Song et al. 2015). There is a clear need for sustainable agricultural innovations that can increase yields and provide food security without incurring environmental degradation. Soil microbes are known to form associations with plants and affect plant health, and in recent years, interest has grown in exploiting the beneficial associations that plants establish with microbes. The plant microbiome abounds with plant growth-promoting rhizobacteria (PGPR) that can help plants acquire more nutrients from the soil and tolerate stressors like drought (Barnawal et al. 2013, Bresson et al. 2014). PGPR can also control plant pathogens (Chowdhury et al. 2013), promote beneficial mycorrhizal colonization (Labbe et al. 2014), and produce potentially valuable secondary metabolites (Raaijmakers et al. 2012). Finding ways to harness these beneficial microbes to improve crop growth and yield has the potential to ameliorate the challenges imposed by the world's growing population and environmental degradation.

 

Department of Project: Stockbridge School of Agriculture

Plant seed oils have tremendous potential as environmentally, economically and technologically feasible replacements for petroleum, but the relatively low oil yields from existing crops limits the commercial viability of seed oil based biofuels.

Therefore, a primary issue of concern with biofuels and bio-products is the ability to produce enough  feedstock oils without displacing food crops. A second major concern is that environmental stresses such as drought, salinity, heat, and exposure to toxic metals adversely affect the growth and productivity of crop plants and thus are serious threats to crop production for food as well as biofuels. Additionally, increase oil contents and composition of fatty acids in edible oil not only improve the food security but will also improve the health of millions of people globally. Our proposed study addresses these fundamental concerns with research to enable the growth of high yield biofuel crops on contaminated and marginal lands without displacing food crop production. Molecular and biochemical approaches are proposed for improving the tolerance of plants to multiple abiotic and oxidative stresses, which will enable biofuel crops to grow on marginal and nutrient poor lands.

During this project, we will identify the key bottlenecks and rate limiting steps in the pathways for Triacylglycerol biosynthesis and storage in seeds. Further we will engineer Camelina sativa, brassica juncea and other related oilseeds crops for higher oil and seeds yields using the candidate genes. Additionally, we will develop "climate-resilient oil seeds crops" by combining enhanced oil and seed yield traits with traits imparting abiotic stresses tolerance in oil seed crops for enabling these crops to grow on nutrient poor marginal lands under changing climate.

We expect to be able to identify key genes/gene networks that limits the accumulation of lipids in seeds using transcriptomic, genomics and metabolomic approaches and  expect to produce genetically engineered oil seed crops with increased oil and seed yield.

Department of Project: Department of Microbiology

Although considerable research has been performed focused on the conversion of biomass to useful products, to date we still have no functional bio-refineries in the US or globally. One of the key problems in the conversion of biomass is known as the "lignin recalcitrance barrier". Lignin is a tough "plastic material" produced by plants that, at the molecular level, coats the "cellulosic" components of biomass that are used to produce most bio-based products and biofuels. Currently some very harsh chemical and heat pre-treatment systems that release cellulosic components from the surrounding lignin barrier are used in pilot scale research for most bio-refineries. To date however, these have been shown to be so harsh that they either damage the cellulose components, they are so polluting that they generate problematic or hazardous wastes, or they simply are so expensive that they cannot be used practically. What our research focuses on is harnessing and utilizing the CMF system that was developed millions of years ago by fungal organisms (a system that has largely been ignored by most scientists interested in biomass conversion). We hope that by harnessing the system that these unique "brown rot" fungi have evolved over the millennia that we can mimic and apply their chemistries to produce biorefinery systems that are more effective, and in particular that are highly energy efficient, cost efficient, safe and non-polluting.

Department of Project: Department of Resource Economics

Residential solar power is an important technological innovation that holds promise for a cleaner energy future. Out of 2.5 million households in the state of Massachusetts, those who installed solar photovoltaic(PV) systems grew from a mere 14 households to 60,465 households between 2010-2017. Between 2015-2017, the residential installations are growing at an even higher rate of 50% (Data source: Massachusetts Department of Energy Resources). It is crucial to understand what factors are determining the household decisions in the process of adopting the solar PV system.

Water

This study will provide important information on long-term trends in water demand and supply, aid in the formulation of water policies for water resource development, and offer information to help protect surface and groundwater supplies. This project will also target areas with the best potential for surface augmentation of water supplies based on the relative benefits and costs of water supply augmentation (through spatially explicit policies for runoff mitigation and groundwater recharge). This project will evaluate water resources within a watershed ecosystem framework, and thereby will consider multiple supplies and uses of water resources. This study will address three areas of special interest to the region, namely:
• Water management in the context of forest loss and rapid development and conflict for water supply;
• Improvements in the assessment of water availability, incorporating technological, institutional, cultural and economic factors that   influence water use and water availability and;
• Improved methods of characterizing and quantifying components of the water cycle in forested watersheds.

Department of Project: Stockbridge School of Agriculture

The goal of the project is to improve irrigation and fertilization practices in ornamental plant production in order to improve production efficiency and to reduce the environmental impact of ornamental plant production by limiting nutrient laden runoff from nurseries and greenhouses. Improving production practices relies on a better understanding of plant water and fertilizer needs as well as assessment of improved application methods. To further improve practices the influence of different soilless media components will be assessed as these components vary in their ability to hold and retain water and nutrients. The use of water holding capacity improving additives such as hydrogels and surfactants will be assessed for use in production and interactions with fertilizers. Improving production practices helps growers to produce the best quality plant possible with the least added inputs in a more environmentally friendly manner.Through this research project a variety of ornamental plants will be grown to assess how production practices can be improved through a series of experiments examining irrigation methods and volume, fertilizer quantity, substrate additives, and substrate components. Plant water needs will be assessed to understand how much irrigation is needed to produce good quality plants.This will provide growers with ways of improving irrigation applications by grouping plants by water needs and reducing irrigation applications when possible. Plant fertilizer needs will be assessed in a similar manner. By reducing fertilizer applications the amount of nutrients in the nursery or greenhouse runoff will be reduced lessening the environmental impact. Substratecomponents and additives will be assessed to further the body of knowledge on their impact on production with an emphasis on their impact on water applications, retention, and leaching and fertilizer retention and uptake.

Department of Project: Stockbridge School of Agriculture

Through this research project a variety of ornamental plants will be grown to assess how production practices can be improved through a series of experiments examining irrigation methods and volume, fertilizer quantity, substrate additives, and substrate components. Plant water needs will be assessed to understand how much irrigation is needed to produce good quality plants. This will provide growers with ways of improving irrigation applications by grouping plants by water needs and reducing irrigation applications when possible. Plant fertilizer needs will be assessed in a similar manner. By reducing fertilizer applications the amount of nutrients in the nursery or greenhouse runoff will be reduced lessening the environmental impact. Substrate components and additives will be assessed to further the body of knowledge on their impact on production with an emphasis on their impact on water applications, retention, and leaching and fertilizer retention and uptake.

Food Science

Department of Project: Department of Food Science

The incidence and prevalence of many chronic diseases are dramatically increasing in the United States and other countries, making these disorders a serious health problem. It is of practical importance to better understand the roles of food-derived bioactive compounds in development of these chronic diseases, in order to provide optimized dietary recommendations or guidelines, and/or develop safe and effective strategies for disease prevention. In this project, we will focus on two major areas: (1) to better understand the effects and mechanisms of food bioactives on development of chronic diseases such a inflammation, aging, and energy metabolism, and (2) to further understand the factors contributing to the poor bioavailability of food bioactives and develop novel strategies to enhance their metabolic stabilities and health-promoting effects. Together, these efforts will provide the fundamental knowledge which is critical to develop safe and effective diet-based strategies for disease prevention, resulting in significant and positive impact for public health.

This project investigates new sustainable markets for New England seafood. Climate change challenges the socio-economic and environmental sustainability of New England's seafood industry. A warming Gulf of Maine compounds the complex puzzle of ecosystems, fish population dynamics, and catch limits for specific fisheries. Cascading effects on fishermen, seafood processors, markets, and restaurants provide a network of challenges that are difficult to disentangle. This multifaceted challenge highlights the need for collaborative, cross-disciplinary research to build sustainable new markets for seafood. This proposal brings together a team with diverse expertise in ecology, climate change adaptation, economics, stakeholder engagement and product development. We aim to support the fishing industry by investigating consumers’ seafood choices, sustainable fishing practices, and seafood products that contain lesser known yet abundant species.   

The work will obtain new data to support ongoing pilot-work and support future proposals. Pilot data include:

  1. Fisherman’s perspectives on local and underutilized fish species and preservation methods,
  2. Consumer acceptability of new artisanal preserved fish products. Seed grant funds will be used to execute semi-structured interviews with New England fisherman, an online consumer survey, and a consumer sensory experiment. These funds will support the collaborative relationship between team members, building an interdisciplinary working group to pursue larger research funds.

Department of Project: Department of Food Science

The results of this project will directly impact industries that handle foods most commonly implicated in foodborne disease outbreaks, including low-moisture foods (especially spices, nuts, and dried fruits); fresh, minimally, and shelf-stable processed produce; dairy; fresh and further processed seafood, meat, and poultry products (including fully cooked and ready-to-eat products subject to post-process contamination), as well as other multi-component and processed foods. Moreover, the threats and specific needs for food safety in the food industry are constantly evolving and require continued risk-based solutions in the face of these changes. Therefore, the project proposes risk-based solutions for the effective control of foodborne pathogens across food commodities in the U.S.

Small dairy farms face particular challenges as costs of production often exceed the set federal price for fluid milk. However, consumers have demonstrated a willingness to pay a premium for local dairy products, providing emerging market opportunities for small dairy farms. In Massachusetts, a significant barrier for dairy farmers hoping to capture this premium is lack of access to scale-appropriate fluid milk processing facilities. This project engagesstakeholders to identify operational feasibility, market potential, and barriers to access institutionalmarkets. Farmers will be engaged to assess the interest and potential supply of fluid milk to the processing facility. Activities including grant workshops and energy efficiency education will assist dairy farmers with maximizing their energy savings, allowing them to lower costs of production. Project activities will engage dairy farmers, academic researchers, agricultural trade and marketing organizations, farmer-owned cooperatives, and institutional buyers.

Department of Project: Stockbridge School of Agriculture

House flies are the major vector of numerous food pathogens (e.g., Escherichia coli). It has been suggested that the fly crop is the major reservoir for the pathogen and also that this is where horizontal transmission of antibiotic resistance occurs. The salivary glands of most flies involved in vectoring pathogens are also involved in pathogen transmission and their nutrient and pathogen uptake while feeding. This research focuses on two essential organ systems of house flies, in order to explore non-traditional control strategies for the insects. Control of flies is thought to have a potential strong impact on transmission of food pathogens.

Department of Project: Department of Food Science

There is a strong association of chronic inflammation with various types of diseases.

However, many of the current treatments for chronic inflammation are limited due to undesirable side effects associated with their long-term use and research has shown bioactive dietary components to be promising candidates for the prevention of inflammation and associated diseases. Thus, the goal of this project is to investigate the role of food bioactives in conjunction with microbiomes in prevention of inflammatory responses.

Department of Project: Department of Food Science

Food safety is very much an agricultural issue.
This multi-researcher project will focus on four critical aspects of food safety: understanding the scope of food safety problems, characterizing the scientific basis of pathogenic organisms' survival, development of methodology for detection, and translating knowledge through food safety extension research and activates. Together these activities will contribute to the long term goal of reducing the overall risk of foodborne illness.

Department of Project: Department of Food Science

The short-term goal of this project is to increase the understanding and mitigating risk factors associated with cleaning,sanitation, cross contamination, detection, and worker behaviors in food production. The long-term goal of this work will help to reduce the overall risk of foodborne illness.

• Objective 1: Understanding of the parameters needed for effective delivery of natural food-grade antimicrobials for use infoods and food processing environments

• Objective 2: Identifying the genetic determinants of Listeria monocytogenes persistence in the food processing environment using genome-wide association (GWA) analysis.

• Objective 3: Mitigating and controlling viral risks to food safety and food production.

• Objectives 4: Conduct applied research relevant to food safety, design supports for adopting practices that will reduce the overall risk of foodborne illness, increase food safety knowledge of producers and processors, and increase access to local and national wholesale markets.

Value-added Food

This project investigates new sustainable markets for New England seafood. Climate change challenges the socio-economic and environmental sustainability of New England's seafood industry. A warming Gulf of Maine compounds the complex puzzle of ecosystems, fish population dynamics, and catch limits for specific fisheries. Cascading effects on fishermen, seafood processors, markets, and restaurants provide a network of challenges that are difficult to disentangle. This multifaceted challenge highlights the need for collaborative, cross-disciplinary research to build sustainable new markets for seafood. This proposal brings together a team with diverse expertise in ecology, climate change adaptation, economics, stakeholder engagement and product development. We aim to support the fishing industry by investigating consumers’ seafood choices, sustainable fishing practices, and seafood products that contain lesser known yet abundant species.   

The work will obtain new data to support ongoing pilot-work and support future proposals. Pilot data include:

  1. Fisherman’s perspectives on local and underutilized fish species and preservation methods,
  2. Consumer acceptability of new artisanal preserved fish products. Seed grant funds will be used to execute semi-structured interviews with New England fisherman, an online consumer survey, and a consumer sensory experiment. These funds will support the collaborative relationship between team members, building an interdisciplinary working group to pursue larger research funds.

Small dairy farms face particular challenges as costs of production often exceed the set federal price for fluid milk. However, consumers have demonstrated a willingness to pay a premium for local dairy products, providing emerging market opportunities for small dairy farms. In Massachusetts, a significant barrier for dairy farmers hoping to capture this premium is lack of access to scale-appropriate fluid milk processing facilities. This project engagesstakeholders to identify operational feasibility, market potential, and barriers to access institutionalmarkets. Farmers will be engaged to assess the interest and potential supply of fluid milk to the processing facility. Activities including grant workshops and energy efficiency education will assist dairy farmers with maximizing their energy savings, allowing them to lower costs of production. Project activities will engage dairy farmers, academic researchers, agricultural trade and marketing organizations, farmer-owned cooperatives, and institutional buyers.

Climate Change

Department of Project: Stockbridge School of Agriculture

The concept of the current experiment is to study carbon storage and possible cycling in soils which alternate between saturation and nonsaturated conditions on an annual basis. To allow the data to be considered robust, or applicable to numerous locations and soil types it will be necessary to have multiple years of data, but to also have data that 'repeats' or replicates itself. Statisticians contend that replicate study areas are required, but it may be that the soil environment is different enough from one place to another that the least variability within the data will come from multiple or replicate data stations within a single area.

The goals and objectives of the project are: To better understand the hydrological, biogeochemical and pedological properties and processes that affect SOM decomposition, CO2 and CH4 greenhouse gas fluxes, and C sequestration in depressional wetland ecosystems, as expressed across geographical and climatic gradients. I also hope to determine the relationship between soil and air temperature and accumulated soil C stocks and fluxes in depressional wetland systems, to determine the relationship between hydroperiod (i.e. duration of saturation and inundation) and accumulated soil C stocks and fluxes in depressional wetlands. Finally, I will seek to develop morphological indices of the hydroperiod within depressional wetlands in order to estimate or predict C
stocks.

Department of Project: Department of Microbiology

Three temperate forage grass species (Lolium perrene, Festuca arundinacea, and Dactylis glomerata) will be grown in 6x10 ft plots under field conditions over the summer at the University of Massachusetts Crop and Animal Research and Education Farm in South Deerfield, Massachusetts. Each species will be grown in 10 replicates for a total of 30 plots. Five replicates of eachs pecies will be treated as well-watered controls and their soil moisture maintained above 25%, while the other five replicates will remain under a water-reduced treatment, receiving no rain or supplemental water. Water reduction will be imposed through the use of rain-out shelters. The shelters will have sides that could roll up and down in order to maintain ambient temperature and allow maximum air flow through the plots on dry days, but will be rolled down on rainy days to keep the water out. Water-reduction conditions will last for 10 weeks, after which rain shelters will be removed and rewatering begins over a period of three weeks in order to stepwise return soil moisture content to above 25%.

Microbial community composition: Throughout the water reduction period, bacterial communities will be sampled once a week for a total of 10 samples and an additional three times during the recovery period. Several mature but not senescent leaves will be collected from each plot for DNA extraction and bacterial cell counts in order to capture a representative community of the whole plot. Samples will be prepared for 16S rRNA sequencing using the Illumina MiSeq platform in two separate pools.  Plant health measurements: To understand how bacterial communities change in relation to changes in the plant, several plant health measurements will be taken. Leaf relative water content, electrolyte leakage, chlorophyll, and soil moisture will be measured every week. Additionally, non-destructive biomass measurements will be taken periodically by measuring leaf height and plot coverage. Plot coverage will be estimated using an elevated quadrat device. At the end of the water reduction period, plots will be divided in half and destructive biomass sampling of one half will provide above ground fresh weight and dry weight measurements. Additionally, roots will be sampled in 15 cm increments to a depth of 60 cm. After soil removal roots will be dried and dry mass measured. 

Nitrogen fixation rates by leaf microbes: Samples will be collected during field studies in the summer and used to quantify potential and actualized nitrogen fixation in the phyllosphere. Additional questions will be focused on understanding how phyllosphere BNF is impacted by plant host species, temporal dynamics, drought, and recovery. To determine the rate of BNF,stable isotope probing will be conducted at 6 different time points. Three samples will be taken during the drought period (week6, 7, 10) and three each week during recovery. Rate of nitrogen fixation will be determined by measuring incorporation of thestable isotope 15N into the leaf tissue. Leaf cuts of known area will be incubated in an artificial atmosphere containing 80% 15N and 20% O2 for 48 hours under ambient light and temperature. Corresponding control samples will be incubated under normal atmosphere to determine natural 15N abundance. After incubation, samples will be dried at 70°C, weighed, finely ground, and 1-2 mg of plant powder will be weighed in tin capsules and sent to a collaborator at the University of Vienna to determine 15N incorporation using a continuous-flow isotope ratio mass spectrometer.  Nitrogen fixation rates can then be determined using the following equation where Nleaf is foliar N concentration, Mr is molecular weight of 15N, and t is incubation time:N2-Fix = Nleaf x (at%15Nsample - at%15Ncontrol)/100 x 103/Mr/tBacterial DNA samples corresponding to each timepoint will be taken to determine the absolute abundance of nitrogen fixing bacteria at each time point as well as to determine their taxonomic identity. The absolute quantity of nitrogen fixing bacteria per leaf area for each of the grass species and treatments will also be determined for the same time points using qPCR of the nifH gene. Next, the rate of nitrogen fixation per nifH copy number will be determined for each grass species under normal and water-stressed conditions. By comparing the three grass host species we will gain a better understanding of how phyllosphere BNF inputs are impacted by plant host species. By directly comparing rates under normal and stressed conditions we will understand how BNF will be influenced in the future by climate stress. Identification of nitrogen fixing members of the bacterial community will be achieved by sequencing the phylogenetic marker genes nifH using the Illumia MiSeq platform. nifH identity,diversity, and richness will be added to the models to better understand biological nitrogen fixation in the phyllosphere.

Department of Project: Stockbridge School of Agriculture

Increasing environmental stresses make crops ever more succeptible to the impact of plant viruses. Plant viruses affect plant functioning and, specifically, the root system. For example, virus infected cover crops may hamper root growth and activity. This may influence the effect of cover crops on the cycling of carbon and other nutrients in soils. Consequently, virus infections may undermine the beneficial use of cover crops to improve soil health, with unclear consequences for soil carbon storage, greenhouse gas emissions, and nutrient status. This project therefore tests how plant virus infection influences the impact of cover crops on soil carbon and nutrient cycling.

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