Optimizing Hydroponic Lettuce Yield: Evaluation of Potassium Source and Concentration with Plant Imaging

Controlled Environment Agriculture (CEA) is an expanding industry in the United States. Lettuce (Lactuca sativa) possesses considerable economic importance as one of the foremost leafy vegetables worldwide in terms of financial value for production in CEA. Rapid growth rate, high yield, and potential return further enhance its suitability for cultivation within CEA. Pursuing optimal and sustainable nutrient concentrations for crops in CEA is a continuous requirement for an expanding industry. This study is set to investigate the impact of different potassium (K) sources and concentrations on 'Green Oakleaf' lettuce growth. The K concentration within the Virginia Tech base hydroponic lettuce fertilizer was increased,1x, 2x, and 3x the normal rates of K ppm, through the addition of potassium chloride (KCl) or potassium sulfate (K2SO4). To account for rising electrical conductivity (EC), due to the increase of K, KCl treatments were recreated with standardized EC through the addition of Sodium Chloride (NaCl). The Spatially and Mechanically Accurate Robotic Table (SMART) in an indoor space was utilized to cultivate and image plant growth over time through pixel count. Growth index and chlorophyll content were recorded weekly, while the fresh weight and dry weight of shoots were recorded at harvest. The KCl treatment with the highest concentration,4x K ppm, as well as those with standardized EC, led to reduced yield when compared to other treatments. All K2SO4 treatments showed no difference in growth when compared to the base solution. K source and concentration, as well as fertilizer EC, were all identified as factors influencing the impact of fertilizers on the optimization of lettuce yield.

Name thesis:degree_name

Master of Science in Life Sciences

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Horticulture

Department dc:contributor.department

Horticulture

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2024

Author dc:creator

• Doss, Mitchell C.

Chair dc:contributor.committeechair

• Evans, Michael Robert

Committee members dc:contributor.committeemember

• Lowman, James Scott
• South, Kaylee Anne

• CEA
• Potassium
• Hydroponics
• Lettuce
• Imaging

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:41556

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/121346