Abstract
One of the consequences of employing artificial lighting to supplement solar irradiance either in a greenhouse [1–3] or in a controlled-environment plant growth chamber, wherein solar irradiance is transmitted through optical cables from solar concentrating systems [4–6], is the subjection of the growing crops to lighting profiles that differ from the conventional lighting profile. The daily lighting profile of a conventional electric-based plant-lighting system can generally be represented by a rectangular wave (Figure 1A) whose height represents the magnitude of the instantaneous photosynthetic photon flux (PPF, in μmol m– 2 sec– 1), whose length represents the daily photoperiod (P, in hr), and whose area represents the daily integrated PPF (Q, in mol m– 2 day– 1). For a hybrid solar and artificial lighting system, the daily lighting profile that results is a composite lighting profile (Figure 1B), typically consisting of an approximately bell-shaped curve, representing the solar component, that is superimposed over a rectangular wave, representing the artificial lighting component. The total of the area under the solar curve and the area of the rectangular wave represents the daily integrated PPF.
Original language | English (US) |
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Title of host publication | Handbook of Plant and Crop Physiology, Second Edition |
Publisher | CRC Press |
Pages | 915-924 |
Number of pages | 10 |
ISBN (Electronic) | 9780203908426 |
ISBN (Print) | 9780824705466 |
DOIs | |
State | Published - Jan 1 2001 |
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Engineering(all)