2024 Research Projects
2024 Research Projects
Home Institution: University of Puerto Rico at Utuado
Mentor: Jonathan Dregni
Faculty Mentor: Dr. Cindy Tong
Gardeners in St. Paul are having difficulty obtaining harvestable Brassica (e.g., broccoli, cauliflower, and collards) crops due to a new insect pest called the swede midge.We need to better understand how to manage this pest in organic systems. Swede midge adults can lay 50 eggs on a plant, which become larvae that could impede head formation in broccoli and cauliflower, and distort leaves. Pupae can overwinter for 3 years under soil. The goals of my project were to examine midge emergence patterns among years, compare infestations on farms versus community gardens, and learn the effectiveness of a system to mitigate midge infestation. Midges were trapped on sticky cards at farms and gardens, and counted using a dissecting microscope. The numbers of unaffected plants in mitigation systems were compared to control plants grown outside the systems. No midges were found on farms, whereas midge numbers were higher in gardens than in previous years aside from one garden, where brassicas had been banned for 3 years. The average 73% of brassicas inside mitigation kits were in good condition, compared to 54% of controls outside the kits.
Soil health is fundamentally influenced by soil organic matter (SOM). It is traditionally measured through lab analysis of soil samples, which can be time intensive and costly. Previous work has shown that SOM is a suitable proxy for soil health and can be measured in real-time by permittivity sensors. This experiment is to determine the correlation between soil permittivity and SOM in annual tilled soy/corn fields and perennial zero-tilled turfgrass fields to aid in soil health evaluation. Composite soil samples were taken at five randomized locations within each field and then sent to the UMN Soil Testing Laboratory for SOM analysis. To measure permittivity, an Acclima TDR 315H soil sensor was inserted into three sub locations within a square meter of the randomized locations. Correlation analysis showed that SOM was positively correlated (r = 0.88) with permittivity in all three fields. An ANOVA showed that SOM and permittivity similarly differentiated between different crop types and tillage (p<0.001). The relationship between SOM and permittivity is significant; therefore, these results suggest that soil health can be estimated by soil permittivity sensing in medium textured soils. Further work should evaluate the on-farm usefulness of this approach for soil health management.
Home Institution: Volunteer State Community College
Mentor: Samikshya Subedi
Faculty Mentor: Dr. Bryan Runck
Home Institution: Smith College
Mentor: Gabriela Hidrobo
Faculty Mentor: Dr. Julie Grossman
Small-scale vegetable production often uses compost to provide nutrients for crops. However, overapplication can exceed crop needs, creating nutrient imbalances and build-up. This issue is exacerbated in high tunnels—commonly used to extend growing seasons—due to high temperatures and lack of rain. In the last decade, nearly 500 small-scale growers have accessed incentives to install high tunnels in Minnesota. As farmers continue to utilize compost and high tunnels, understanding the effects of these practices on soil carbon pools and soil nutrient dynamics is crucial. This study assessed soil carbon pools in 100 vegetable farms across Minnesota using Permanganate Oxidizable Carbon (POXC) analysis to measure labile carbon. POXC is a fraction of the soil organic matter pool, correlating positively with organic matter, and possibly with Phosphorus (P) and Potassium (K). POXC has been shown to be more sensitive to changes in management practices than total organic carbon. We expected high POXC levels due to overcomposting, especially in organic farms, with higher levels in high tunnels due to their unique conditions. Our results confirmed high POXC levels, particularly in high tunnels and organic farms. These results suggest farmers can reduce compost use, alleviating environmental challenges and reducing costs.
White mold (Sclerotinia sclerotiorium) is a devastating plant pathogen causing substantial yield losses across hundreds of plant species. Despite initial success of fungicides, S. sclerotiorium has been shown to develop resistance when the chemicals are applied in small doses for prolonged periods of time. This study investigates the efficacy of biocontrol agents in managing S. sclerotiorum Stem Rot (SSR) in canola, an under-researched crop in this context. Various biocontrol agents including Coniothyrium Minitans (Contans), Bacillus amyloliquefaciens (Double Nickle LC), Bacillus subtilis (Serenade OPTI), and Endura (Boscalid) were applied at different bloom stages in randomized plots of a canola SSR-infected field. Treatments involved both individual and combined applications of these agents. Additionally, the field contained buried bags of sclerotia, the resting structures of the mold. Evaluation protocols included disease ratings, calculating disease severity index (DSI), yield assessment at harvest, and analysis of mycelial growth in cultures alongside microbial work and DNA extractions for the sclerotia. Plots containing Bacillus subtilis proved to be the most promising in managing disease based off the DSI calculations. Interestingly, the DSI in the Contans plots was higher than the untreated plot. Sclerotia viability assays from the Contans and untreated plots were also consistent with these results.
Home Institution: Berea College
Mentors: Alisha Hershman and Hunter Klugel
Faculty Mentor: Dr. Megan McCaghey
Home Institution: Winona State University
Mentor: Cristina Perez
Faculty Mentor: Dr. Mary Rogers
Brassicaceae crops such as kale, broccoli, cabbage, and cauliflower are popular vegetables for the fresh market but experience damage from various insect pests, especially in organic production systems. Common pests include flea beetles, imported cabbageworm, diamondback moth, and cabbage looper. This study compared different mulch types, including reflective and black film, to bare soil to assess impacts on pest pressure. The experiment used a randomized complete block design with four brassica varieties: ‘Red Russian’ and ‘White Russian’ kale, ‘Novantina’ broccoli raab, and ‘Gypsy’ broccoli. Each week, caterpillars were counted on five random sample plants from each treatment and variety, and marketable fresh weight was collected. A Wilcoxon test determined if pest presence and marketable fresh weight differed among mulches. Results showed that the mean number of caterpillars for Novantina, Gypsy, and White Russian kale did not significantly differ among mulch types (p=.1136, p=.883, p=.2011, respectively). However, for Red Russian kale, the difference was significant (p=.0026). The mean weight of marketable harvest differed significantly among treatments for White Russian and Red Russian Kale (p=.01064, p=.00324).
Alfalfa has been bred to have reduced lignin in stems to improve cattle digestibility and increase milk production, but it remains unclear how forage lignin content impacts root architecture and chemistry. Variation in these root traits among lines differing in stem lignin content could have implications for global carbon and nitrogen cycling. We evaluated tap and fine roots of three alfalfa lines varying in stem lignin content for biomass, surface area, length, lignin content, and the carbon-to-nitrogen ratio (C:N). Roots were excavated at the early flower stage in St. Paul and Rosemount, MN, from three-year-old alfalfa stands. The increased lignin line had the highest mean C:N, suggesting reduced root decomposition compared to the other lines. The reduced lignin line had the largest fine root biomass, so although it had a lower C:N than the others, it had the largest carbon and nitrogen inputs to the soil. We predict that stem lignin content is positively associated with root lignin content. These data show that variation in stem lignin influences root architecture and chemistry, and that reduced lignin lines can contribute labile C and N to the soil via high root biomass with stoichiometry conducive to nutrient cycling.
Home Institution: Utah State University
Mentor: Hannah Rusch
Faculty Mentor: Dr. Jake Jungers
Home Institution: Michigan State University
Mentors: Nora Pearson and Morgan Smith
Faculty Mentor: Dr. Nicolas Jelinski
Many studies have demonstrated the negative health effects associated with the abundance of microplastics in water systems. However, few have considered the abundance of microplastics in inland soil, which is important knowledge for soil toxicity, nutrient mobility, and moisture diffusion in soil. Similarly, there isn’t a thorough and repeatable method for quantifying microplastics in soil. This study was conducted to test methods of quantifying the amount of microplastics in soil samples collected from the city of South St. Paul (MN) Parks System. Soil samples were collected from each horizon. For this, 10 related methods were evaluated, with variables including reagents, filter type, method of extraction, use of hydrogen peroxide, and drying time changed with each iteration. The most effective method for quantifying microplastic content was separating samples in double deionized water and placed directly onto a slide for ease with using confocal microscopy. This method was then used to quantify microplastics in 47 samples, expected results are higher concentration of microplastics in higher soil horizons. Given the results of this study, a future study measuring the types and sources of microplastics in these soil samples should be conducted in order to further understand the impacts of this contamination.
Blackspot bruise is an internal defect in potatoes that causes major economic losses as many varieties remain susceptible. There are no standardized methodologies to screen for blackspot bruise vulnerability. This study was conducted to develop a standard protocol to screen for bruise resistance and enable the efficient selections of potatoes to breed more resistant varieties. The effect of different storage times, storage temperatures, and tumbling times were evaluated to determine the procedure that induced bruise development. Susceptibility was measured by bruise incidence, color, and severity. A lower pulp temperature at the time of impact, moderate tumbling duration, and warm post-impact storage conditions led to the most significant bruising. Severity was found to be a more reliable metric than incidence to assess bruise susceptibility. An index was calculated to accurately assess blackspot bruise resistance.
Home Institution: University of California, Davis
Mentor: Fang Wang
Faculty Mentor: Dr. Laura Shannon
Home Institution: University of Florida
Mentors: Kat LaBine and Leah Hallett
Faculty Mentors: Dr. Jessica Gutknecht and Dr. Anna Cates
Soil erosion is a leading concern for farmers and policymakers as extreme weather events remove more topsoil yearly. Measuring erosion is often an expensive task done with edge-of-field (EOF) monitoring technology, so this project aims to investigate an accurate, more accessible alternative method of measuring soil erosion using fabric erosion mats. Erosion mats are 6x6 inch squares of porous mesh fabric staked to the soil surface that can catch sediment moved by water in fields. One group of mats was deployed at the Farm at the Arboretum in different cropping systems. Based on ANOVA tests, the mats were able to detect that perennial Kernza had less erosion than most other cropping systems while soybeans without cover crops usually had the most erosion. The second group of mats was deployed at two Discovery Farms sites (Marathon, WI and Redwood, MN). The soil sediment and nitrate from mats were compared to EOF total suspended solids (TSS) and nitrogen. There are correlations between in-field measurements and EOF data, but this method should be investigated further as a tool to measure progress in farm management and soil conservation.
Corn and soybeans are the most economically valuable crops in Minnesota and represent significant land usage in the state with farmers reporting 14.5 million acres of corn and 7 million acres of soybeans planted in 2024. Continued warming and fluctuations between extreme weather events driven by climate change are expected to increase pest pressure, flood damage, and risk of heat stress for crops and farmworkers. Six climate-conscious commercial corn and soybean farmers located predominantly in southern Minnesota were interviewed to understand their perceived extreme weather and climate impacts, farm management responses to these conditions, and risk management concerns for their farm’s future. These semi structured interviews were recorded, transcribed, and underwent a preliminary analysis of key concerns to ground the development of an interactive decision-making tool. The goal of this research is to help farmers and their agricultural advisors assess their agricultural risks due to climate change and the actions they can take to prepare for Minnesota’s extreme weather and climate impacts. We expect that findings from our research will inform our ability to advise on best climate preparedness practices for short term (in season), mid term (1-3 years), and long term (10-15 year) time horizons.
Home Institution: University of South Florida
Mentor: Katie Black
Faculty Mentor: Dr. Nathan Meyer