CEFS Agroecology Scholars Program in Research and Extension (ASPIRE)
2021 Research Areas
Are we selecting for more aggressive weeds?
Faculty Mentor: Dr. Ramon Leon
Location: NC State Main Campus (Raleigh, NC)
Weeds are one of the most pervasive and constant threats to food security, and also one of the most challenging to address due to limited control tools and widespread herbicide resistance (HR). This problem has recently become particularly serious because there are weed species that have evolved resistance to almost all site of actions (SOA), and no new SOA has been registered in almost 30 years. Despite their importance, weeds adaptability and success in agroecosystems is not well understood. The NCSU Weed Ecology Laboratory has been studying how weeds evolve and adapt to changes in weed control practices using historical seed bank collections of weeds of economic importance. This information is critical to anticipate how weeds will adapt to non-chemical weed control practices. The goal of the present study is to characterize phenotypic and genetic variation among different generations of weed populations collected over a thirty year period throughout which weed management practices changed dramatically.
The student will develop skills in plant identification, morphology, growth analysis, production, and in genetic techniques such as DNA extraction and purification. The knowledge acquired during the study has direct applications for working on germplasm conservation and plant breeding.
The candidate has to be interested in plant ecology and biology as well as agriculture. It is very important that the candidate is very detail oriented, can manage large data sets, and keeps organized records. Furthermore, the study requires working under hot and humid conditions in the field and greenhouse, as well under controlled conditions in the lab. The candidate should be willing to handle chemicals for experimental purposes. Finally, the candidate should have excellent interpersonal skills.
Resilience in Pasture-based Systems and COVID-19
Faculty Mentor: Dr. Francesco Tiezzi
Research Question: The current COVID-19 pandemic raises important questions about the
resilience of small and medium-size pasture-based dairy and hog farms. Resilience is about the
capacity of a farm to persist, adapt and transform when confronted with a major challenge. News
reports on possible scarcity of consumer products due to shutdowns at meatpacking plants and
the dumping of milk have impacted Americans’ confidence in their food supply. The pandemic-
induced disruption has interacted with ongoing trends in dairy and hog production, such as the
declining number of small and medium-size dairy farms, the consolidation of meatpacking, and
related concerns about the impacts of contractual integration on farmers and rural communities.
Will current farm loss trends in small and medium-size pasture-based dairies continue? Will the
pandemic lead to a decline in small and medium-sized pasture-based hog farms, which in
contrast with dairy have not experienced a farm loss and consolidation trend? That is, how
resilient are American small and medium-size pasture-based dairy and hog operations when
challenged by pandemic-induced conditions?
Study Proposal: This study will recruit small and medium-sized dairy and hog farmers to
participate in open-ended interviews via Zoom and telephone. Working with Cooperative
Extension and NC Choices, we will identify a varied set of small and medium-size, North
Carolina pasture-based dairy and hog farmers differentiated about socioeconomic well being,
production, processing, and distribution practices, and animal welfare before and during COVID-
19. Interviews will be recorded and then transcribed and analyzed to describe how different types
of farmers and their households may, or may not, have adapted in relation to pandemic-induced
conditions.
Skills Required: A basic understanding of livestock farming and/or qualitative social research.
The student will be transcribing interviews The student should be prepared to read and
summarize academic literature related to the social and animal science aspects of small and
medium-size, pasture-based livestock production. The student should also be able to write a short
article for popular press. As part of this experience, the student will need to complete NC State
IRB/CITI on-line courses for research with human subjects if she/he/they does not already have
certification from their college/university.
Student Engagement and Outcome: The student will have weekly meetings with an
interdisciplinary research team to discuss academic literature, qualitative data, and sustainable
livestock production. At the end, the student will produce a popular publication discussing what
they learned from the data and their experience.
Nitrogen Dynamics Under Polyethylene Mulches for Organic Cropping Systems
Faculty Mentor: Dr. David Suchoff
Location: NC State Main Campus (Raleigh, NC) and Cunningham Research Station (Kinston, NC)
Polyethylene plastic mulches are commonly used in high value crop production to manage in-row weed populations, buffer soil temperatures, conserve soil moisture and limit soil erosion. Mulch color and reflectiveness may also deter insect pests such as aphids and thrips or increase plant secondary metabolite biosynthesis. Comparatively little research has been done on the potential impact on microbial dynamics in the soil, which can have a drastic impact on nitrogen (N) mineralization and subsequent crop N uptake.
The goals of this project are to 1) monitor soil temperature differences under different colors of polyethylene mulches, and 2) determine if these differences affect nitrogen mineralization dynamics of organic amendments. This will be accomplished by establishing two field experiments in Eastern North Carolina comparing four mulch colors with uncovered soil. Temperature sensors embedded in each treatment will track diurnal and seasonal temperature dynamics. To quantify potentially available nitrogen (PAN), the student will repeatedly soil sample the field sites. Samples will be processed and analyzed in the EATS Lab on NCSU main campus in Raleigh, NC. Students will conduct an extraction procedure to determine inorganic nitrogen and will have the opportunity to be trained on a flow-injection colorimetric analyzer.
Results from this research will allow for refinement of nitrogen management on organic farms utilizing mulches to manage weeds and insect pests. Quantifying PAN release under the different colors of mulches will potentially enable growers to make decisions that increase nitrogen use efficiency and crop profitability while minimizing environmental impact.
The student should have an interest in sustainable agriculture and fieldwork (experience preferred but not required). Training will be provided for all field research and lab skills needed to successfully conduct the project. General understanding of biological and chemical concepts relating to plants and soil would be helpful, as well as the ability to work outdoors in the summer heat and maintain a positive attitude.
Manage Bacterial Angular Leaf Spot (BALS) Across Seed and Food Production Systems
Faculty Mentor: Alejandra Huerta
Location: NC State Main Campus (Raleigh, NC)
Bacterial Angular Leaf Spot (BALS) is a plant disease caused by multiple groups (pathovars) of the plant pathogenic bacteria Pseudomonas syringae. Some strains of this pathogen are seedborne and can infect both true seed and fresh food crops of cucurbit, chard, and beet (CCB). Seed infestation contributes to disease onset, and thus, limits production of CCB nationwide and in some cases can negatively impact international trade. The occurrence and severity of the disease has increased in recent years in many regions of production, but detection of the pathogen in seed has largely lagged behind. The lack of sensitive, robust, and specific detection method for pathogenic strains of Pseudomonas syringae pathovar aptata, a subgroup within the Pseudomonas syringae species, has led to a significant gap in disease management for BALS on CBB. The seedborne nature of this pathogen, their genetic similarity to non-pathogenic strains, and their wide host range have made it a very challenging disease to manage. The short-term goal of this study is to isolate and characterize Pseudomonas syringae strains from CBB seed. The long-term term goal is to design robust, sensitive and specific molecular markers for the detections of Pseudomonas syringae pathovar aptata.
Learning Goals: The selected student will contribute to the development of an economically-sound, integrated approach to manage BALS across seed and food production systems, to ensure high-quality seed and food crops. The student will learn and apply general concepts of plant pathology, the study of diseases of plants, and molecular biology. Student will gain skills on aseptic technique, bacterial culturing, pathogen inoculation on plant hosts, bacterial enumeration, data management, molecular biology, routine bacterial characterization methods and science communication. The proposed work will be carried out in the greenhouse, growth chamber, laboratory and office. The majority of the work will be conducted in the laboratory and will include growing and maintaining bacterial cultures, making media, transferring bacteria, growing plant for inoculation assays and performing pathogenicity studies in the greenhouse/growth chamber. Office work will include data analysis and bacterial database generation.
Preferred Skills: The ideal candidate should have a strong work ethic, be self-motivated and dedicated to their assigned project. It is important that the student contribute to a positive and respectful lab environment where everyone feels welcomed. Preference will be given to students that have a strong interest in plant pathology, bacteria-plant interaction and bacteriology.
Identification of Resistance to Ascochyta blight (Mycosphaerella pinodes) in the USDA Pea Single Plant-Derived (PSP) Core Collection
Faculty Mentor: Chris Reberg-Horton
Student Mentor: Lais Bastos Martins
Location: NC State Main Campus (Raleigh, NC)
North Carolina is the second producer of hogs and pigs in the U.S but needs to import about half of its grain feed every year. Peas are a good ingredient in animal feed, due to the high protein content. Furthermore, in North Carolina, they can be grown over the winter and not compete with soybean, allowing them to be used as a new source of protein in animal feed. Peas can also serve as a cover crop, contributing to biomass and N to the soil. One of the major impediments for pea production in the south is diseases. Ascochyta blight (Mycosphaerella pinodes) is of the major diseases of peas worldwide and can severely affect pea production in NC. Finding lines that show resistance to the disease will help the breeding efforts to produce healthier plants either for feed or cover crop use. We will screen a USDA collection of peas by growing the plants in a growth chamber, inoculating and then scoring for disease resistance/susceptibility. The phenotyping information along with existing genotypic data will be used to find regions on the genome associated with ascochyta blight resistance.
If interested, the student will also be able to learn and help with different projects in the Reberg-Horton lab, including: allelopathy in rye, cameras that can detect water stress in field crops, cover crop breeding and others.
The student will be exposed to aspects of plant breeding, plant pathology, experimental design, statistical concepts and use of controlled environment. Interest in these topics, organization skills and attention to detail are required.
Does organic farming promote soil microbial communities with high nitrogen use efficiency in acidic Southeastern US soils?
Faculty Mentor: Shuijin Hu
Postdoc Mentor: Sean Bloszies
Location: NC State Main Campus
Nitrous oxide emissions originating from nitrogen fertilizer applications is a powerful global warming gas and contributes 87% of US agricultural greenhouse gas emissions. Because organic agriculture is characterized by the use of alternative nutrient and organic matter inputs, soil nitrogen cycling differs from that in conventional agricultural fields. In particular, differences in soil microbial nitrifyer and denitrifyer communities may be driven by altered physical and chemical properties in soil managed under organic practices. However, there is not yet a clear understanding of how community structure contributes to N2O emissions. The goal of this study is to link soil properties like pH and soil carbon pools, functional gene abundances indicative of key microbial groups, and rates of nitrogen transformations like N mineralization and denitrification.
The student will gain skills in methods of field sampling, laboratory microcosm experiments, and quantitative molecular biology. In addition, the student will learn principles of applied ecology. Work will be conducted in the field, lab, and office. Field work will include soil sampling in North Carolina during the summer. Lab work will consist of tasks that require a high attention to detail, such as DNA and nutrient extractions from soil. Office work will consist of entering and manipulating data.
The candidate must be interested in molecular biology, multivariate statistics, and answering questions applicable to both basic and applied problems. Ideal candidate should have some college education in chemistry, ecology and molecular biology or work experience in agriculture. Desired skills are some experience manipulating data in spreadsheet software or using scripts.
Effects of long-term manure application on crop nitrogen needs
Faculty Mentor: Stephanie Kulesza
Graduate Student Mentor: Joe Burns
Location: NC State Main Campus (with travel to field sites for sampling)
Poultry litter is an abundant fertilizer resource in North Carolina. With a booming poultry industry in the state, farmers are utilizing poultry litter as an inexpensive fertilizer in many different cropping systems. Because poultry litter is often applied annually, it is important to understand the fertilizer value of these materials, nutrient cycling dynamics after application, and the impact of repeated application on residual soil nitrogen. Therefore, the student working on this project will identify the impact of long-term manure application on residual soil nitrogen and the nitrogen availability of poultry litter applied to three soils in North Carolina.
This project will consist of lab incubation studies and field soil collection and analysis. The student will participate in project setup, maintenance, sample collection, soil extraction, data entry, and data analysis. The ideal candidate should have an interest in soil fertility and nutrient management or a related field (soil science, chemistry, etc.)
Agricultural Economics
Mentor: Kathryn Boys
The specific project will depend on the student’s interests, but will be in one of the projects that Dr. Boys is currently working on:
- Contemporary Organic Policy
- Food Loss and Food Waste
- Economic Considerations of Food Safety
- Intersections Between Food Systems and Health
Evaluating Crabgrass as a forage and nutrient receiver
Faculty Mentor: Miguel Castillo
Graduate Student Mentor: Stephanie Sosinski
Traditionally, crabgrass was recognized as a relatively unmanaged volunteer grass species in grazing or dual-cropping systems. However, research efforts have brought to market improved forage cultivars of crabgrass such us ‘Red River’, ‘Quick-N-Big®’, and ‘Impact. The overall goals of the project are to determine the value of crabgrass as a forage and nutrient receiver crop and to assess the N-mineralization rates when poultry litter is used to fertilize crabgrass. This project is part of the MS thesis of Stephanie Sosinski and it is expected that the undergraduate will join and contribute to the sucess of the project. Plots will be established at the Piedmont Research Station in Salisbury and the activities will also include laboratory tasks.