PhD Candidate · Department of Plant and Agroecosystem Sciences
University of Wisconsin–Madison
My current research focuses on using hyperspectral imagery for nitrogen management in vegetable crops such as snap beans and kidney beans on irrigated sandy soils in Wisconsin.
What I work on
Vegetable growers in Wisconsin's Central Sands face a critical trade-off: applying enough nitrogen to maximize yield while avoiding excess that leaches into groundwater on these highly sandy, irrigated soils. My doctoral research shows that across multiple growing seasons in snap beans and kidney beans, the economically optimal nitrogen rate is consistently lower than the agronomically optimal rate—meaning the marginal yield gain from extra fertilizer does not justify the added cost or environmental risk. This finding directly supports more sustainable and cost-effective nitrogen management for vegetable producers.
Traditional in-season nitrogen assessments require destructive tissue sampling—costly, time-consuming, and impractical at field scale. I collect aerial hyperspectral imagery using HySpex sensors (400–2400 nm) on a weekly basis across snap bean and kidney bean field trials. My work shows that SWIR wavelengths are most informative at early growth stages, while visible and NIR regions dominate later in the season. Combining spectral features with genetics, environment, and management (GEM) factors in Random Forest and PLSR models substantially improves prediction accuracy for both yield and nitrogen status.
Aerial imagery collected over vegetable fields inevitably captures mixed plant–soil pixels, especially at early growth stages when canopy cover is sparse. I systematically evaluated NDVI threshold values (0.1–0.7) for separating plant and soil spectra across different growth stages of snap beans and kidney beans. The results show that a lower NDVI threshold (0.3) is needed early in the season to accurately exclude bare soil, while higher thresholds are appropriate later. This preprocessing framework is now applicable to other row crops with similar canopy development patterns.
My master's research at Tennessee State University examined how nitrogen fertilizer rates and cultivar choice affect winter canola (Brassica napus L.) productivity, seed quality, and pollinator communities. Using field trials in middle Tennessee, I quantified nitrogen effects on yield, seed oil content, and protein content, while simultaneously monitoring pollinator visitation using sticky traps, pan traps, and sweep nets. I also characterized floral volatile compounds using electronic nose (e-nose) sensing coupled with multivariate analysis to understand how nitrogen alters chemical signals that attract pollinators—a study that bridges agronomy and chemical ecology.
Peer-reviewed work
A comprehensive comparison of multispectral and hyperspectral imagery for plot-level crop yield prediction of kidney beans, snap beans, and potatoes
Smart Agricultural Technology, 2026
Characterization of volatile compounds in winter canola (Brassica napus L.) flowers for pollinator attraction by electronic nose
Agrosystems, Geosciences and Environment, 2025 (under revision)
A comprehensive review of high throughput phenotyping and machine learning for plant stress phenotyping
Phenomics, 2022
Nitrogen and variety effects on winter canola mortality, shatter, yield and quality
Agrosystems, Geosciences and Environment, 2020
Comparison of winter canola cultivars in middle Tennessee (Extension Factsheet)
Tennessee State University Cooperative Extension Program, ANRB17, 2020
Manuscripts in preparation (expected submission within 2 months)
Conference presentations
Understanding Nitrogen Responses of Processing Vegetable Crops Grown on Irrigated Sandy Soils Using Hyperspectral Imagery Oral
CANVAS Meeting, Salt Lake City, UT
Leveraging Hyperspectral Remote Sensing for Studying Response of Snap Beans (Phaseolus vulgaris L.) to Nitrogen Oral
ASA, CSSA, SSSA International Annual Meeting, San Antonio, TX
Predictive Models for Snap Beans Under Varied N Rates Using Hyperspectral Imagery Poster 2nd Prize · Diversity Finalist
ASA, CSSA, SSSA International Annual Meeting, San Antonio, TX
Predictive Models for Snap Beans Under Varied N Rates Using Hyperspectral Imagery Poster
PSGSC Symposium, Madison, WI
Predictive Models for Vegetable Crops Under Varied N Rates Using Hyperspectral Imagery Poster
North American Plant Phenotyping Network (NAPPN) Conference, Purdue University, West Lafayette, IN
Eye in the Sky: Hyperspectral Imaging for Sustainable Nitrogen Management in Vegetables Lightning Talk
North American Plant Phenotyping Network (NAPPN) Conference, Purdue University, West Lafayette, IN
Predictive Models for Vegetable Crops Under Varied N Rates Using Hyperspectral Imagery Poster
WPVGA Conference, Stevens Point, WI
Eye in the Sky: Aerial Imaging for Sustainable Nitrogen Management in Processing Vegetable Crops Oral
Wisconsin Agribusiness Classic, Madison, WI
Invited Graduate Student Speaker Invited
Cornell Corteva Symposium
Using Hyperspectral Remote Sensing for Understanding Response of Snap Beans (Phaseolus vulgaris L.) to Nitrogen Oral 1st Prize
ASA, CSSA, SSSA International Annual Meeting, St Louis, MO
Hyperspectral Signatures as Plant Fingerprints Rapid Talk · Poster
ASA, CSSA, SSSA International Annual Meeting, St Louis, MO
Eye in the Sky: Hyperspectral Imagery for Nitrogen Management of Vegetable Crops Lightning Talk 2nd Prize
Association of Horticulturists of Indian Subcontinent Interest Group Lightning Talk Competition, Virtual
Hyperspectral Signatures as Plant Fingerprints Lightning Talk
PSGSC Symposium, Madison, WI
Eye in the Sky: Sustainable Nitrogen Management Using Hyperspectral Imagery Poster
PSGSC Symposium, Madison, WI
Eye in the Sky: Sustainable Nitrogen Management Using Hyperspectral Imagery Poster
Women in Science and Engineering (WISE) Graduate and Undergraduate Poster Session, Madison, WI
Eye in the Sky: Predicting Crop Nutrient Status and Crop Yield Poster
Sustainability Symposium, Madison, WI
Eye in the Sky: Predicting Crop Nutrient Status and Crop Yield Poster
UW-Madison Day, Madison, WI
Response of Kidney Beans and Snap Beans to Nitrogen Management 5-min Talk
PSGSC Symposium, Madison, WI
Pollinators and Monitoring Options for Winter Canola (Brassica napus L.) in Tennessee Oral
Tennessee State University University-Wide Research Symposium, Nashville, TN
Recent Winter Canola Research in Tennessee: Yield, Oil, Protein and Pollinators Oral
U.S. Canola Association Fall Meeting, Virtual
Effect of Nitrogen Fertilizer on Yield, Oil and Protein Content and Pollinators of Winter Canola Oral 2nd Prize
ASA, CSSA, SSSA International Annual Meeting, Salt Lake City, UT
Effect of Temperature on the Seed Germination of Winter Canola Oral 1st Prize
Tennessee State University University-Wide Research Symposium, Nashville, TN
Characterization of Volatile Compounds in Canola Flowers for Pollinator Attraction Oral 1st Prize
Tennessee Academy of Sciences, Nashville, TN
Characterization of Volatile Compounds in Canola Flowers for Pollinator Attraction Poster
Research Gala, Vanderbilt University, Nashville, TN
Courses & practicum
Recognition
Get in touch
University email: tgill4@wisc.edu
Personal email: gtaqdeer1@gmail.com
Department of Plant and Agroecosystem Sciences
University of Wisconsin–Madison, Madison, WI
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