IMPACT OF PLANT POPULATION ON AGRONOMIC PERFORMANCE, LABOR REQUIREMENTS, AND LEAF QUALITY IN BURLEY TOBACCO (NICOTIANA TABACUM L.)

Author

Sarah E. Graham, University of Tennessee, KnoxvilleFollow

Date of Award

8-2025

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant Sciences

Major Professor

Mitchell D. Richmond

Committee Members

Virginia R. Sykes, Margarita M. Velandia, Lori A. Duncan

Abstract

Increased labor costs and perceived yield declines have prompted burley tobacco (Nicotiana tabacum L.) producers to reconsider conventional plant populations. This study evaluated the effects of three planting densities, including 11,532, 17,574, and 23,065 plants ha^-1,on agronomic performance, cured leaf yield, labor requirements, and leaf quality in three burley tobacco cultivars (TN90LC, KT204LC, and KT222LC). Field trials were conducted over two years at the University of Tennessee’s Northeast Tennessee (NETREC) and Highland Rim (HRREC) AgResearch and Education Centers using a randomized complete block design with factorial arrangement. Key metrics assessed included plant height, leaf number, stem diameter, total yield, and USDA federal grade index, as well as labor requirements for harvest and stripping. Yield was significantly impacted by cultivar selection and plant population, with modern burley tobacco hybrids (KT204LC and KT222LC) performing better than the older cultivar, TN90LC. Results demonstrated that increasing plant population significantly improved total cured leaf yield without significantly impacting leaf quality. However, labor hours for harvest and stripping increased by 24–31% under the highest plant density. Despite improved yields, partial budget analysis revealed diminishing returns at the highest density due to the increased input costs, mostly associated with labor, resulting in negative changes in net profit. Conversely, reducing population density lowered input cost but also reduced yield and potential revenue. Under the production and market conditions of this study, the recommended population of 17,574 plants ha^-1 remains the most economically and agronomically sustainable choice for burley tobacco producers; however, the increases in labor costs and decrease in labor supply could prompt tobacco producers to choose planting densities which fall between 11,532 and 17,574 plants ha^-1.

Recommended Citation

Graham, Sarah E., "IMPACT OF PLANT POPULATION ON AGRONOMIC PERFORMANCE, LABOR REQUIREMENTS, AND LEAF QUALITY IN BURLEY TOBACCO (NICOTIANA TABACUM L.). " Master's Thesis, University of Tennessee, 2025.
https://trace.tennessee.edu/utk_gradthes/14496