Life Sciences Commons^™

Efficacy Of Two Hortiled Fixtures, Jakob Johnson, Paul Kusuma, Bruce Bugbee

Controlled Environments

We tested the efficacy of the Full Spectrum and Red-Blue HORTILED TOP LED fixtures manufactured by PL Light. Both fixtures had an 80° light distribution.

The efficacy of the fixtures was measured using flat plane integration as described by Nelson and Bugbee (2014)¹ (see adjacent photo). The fixtures were suspended at 0.65 m above the floor in a 3 × 3 m room with flat black walls. The photosynthetic photon flux density (PPFD, μmol · m^-2 · s^-1) was measured with a recently calibrated quantum sensor (LI-COR model 190R). Measurements were made 2.5 cm apart near …

Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Stott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tree fruit crops are of high value, but use a lot of water. Precision irrigation has the potential to save water while simultaneously improving crop quality. The timing and method of precision water stress in various tree fruit crops has been widely studied. However, in order to successfully employ precision irrigation methods in orchards, an accurate measurement of tree water status is required. Currently, stem water potential is the preferred indicator. However, this measurement is tedious and cannot be automated. Because measurements must be taken near solar noon (approximately 1:30 PM MDT in the summer in northern Utah), the number …

Double-Ended High Pressure Sodium Fixtures Decline Less Than 6% Over 2 Years And 5000 Hours, Jakob Johnson, Bruce Bugbee

Publications

Double-ended (DE) high pressure sodium (HPS) lights with electronic ballasts are reported to age more slowly than the old mogul base technology with magnetic ballasts, but aging has not been well studied in a greenhouse environment. Both dirt accumulation and age can decrease output.