Sunfleck dynamics in relation to canopy structure in a soybean (Glycine max (L.) Merr.) canopy

Robert W. Pearcy, John S. Roden, John A. Gamon

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


The spatial and temporal distributions of sunflecks in a soybean canopy were quantified with an array of photocells and a data logger that measured photosynthetic photon flux density (PFD) at either 0.05-or 1-s intervals. The number of sunflecks recorded per day ranged from 500 to 1800 at cumulative leaf area indices (LAI) of 0.5, and from zero to 500 at positions with cumulative LAI > 3. The most frequent class of sunflecks was 0.4-0.8 s in duration. However, sunflecks shorter than 1.6 s contributed only 6.7% of the PFD available for photosynthesis. Most sunflecks were separated by only a short low-light interval with > 60% occurring within 6 s of a previous sunfleck. Sunflecks contributed 20-93% of the total daily PFD at locations receiving sunflecks. The potential role of the observed sunfleck characteristics in photosynthesis is discussed.

Original languageEnglish (US)
Pages (from-to)359-372
Number of pages14
JournalAgricultural and Forest Meteorology
Issue number3-4
StatePublished - Sep 1990
Externally publishedYes

ASJC Scopus subject areas

  • Forestry
  • Global and Planetary Change
  • Agronomy and Crop Science
  • Atmospheric Science


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