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| Web URL(s): | https://dl.sciencesocieties.org/publications/aj/articles/96/6/1562
Last checked: 11/02/2016
Access conditions: Item is within a imited-access website |
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| Publication Type:
| Refereed |
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| Author(s): | Shulski, Martha D.;
Walter-Shea, Elizabeth A.;
Hubbard, Kenneth G.;
Yuen, Gary Y.;
Horst, Garald |
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| Author Affiliation: | Shulski: Geophysical Instutition, University of Alaska, Fairbanks, Alaska; Walter-Shea and Hubbard: School of Natural Resources, Universtiy of Nebraska, Lincoln, Nebraska; Yuen: Department of Plant Pathology, Univ. of Nebraska; and Horst: Department of Agronomy and Horticulture, University of Nebraska |
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| Title: | Penetration of photosynthetically active and untraviolet radiation into alfalfa and tall fescue canopies |
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| Source: | Agronomy Journal. Vol. 96, No. 6, November/December 2004, p. 1562-1571. |
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| Publishing Information: | Madison, WI: American Society of Agronomy |
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| # of Pages: | 10 |
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| Keywords: | TIC Keywords: Ultraviolet Radiation; Susceptibility; Photosynthesis; Irradiance; Medicago sativa; Festuca arundinacea; Solar radiation; Light penetration; Canopy; Transpiration; Ozone
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| Abstract/Contents: | "Ultraviolet-B radiation (UV-B, 280-320 nm) reaching the earth's surface has deleterious effects on plants. The degree of susceptibility to UV-B is dependent on the amount of energy present in longer wavelengths of ultraviolet-A radiation (UV-A, 320-400 nm) and photosynthetically active radiation (PAR, 400-700 nm). This study was conducted to quantify the UV and PAR light environment and describe the UV-B/UV-A, and UV-B/PAR ratios above and below developing vegetative canopies. Transmitted irradiant flux densities of UV-B, UV-A, and PAR in a developing alfalfa (Medicago sativa L.) canopy and tall a fescue (Festuca arundinacea Schreb.) canopy were measured at varying solar zenith angles under clear and overcast sky conditions. Extinction coefficients for average transmittance differed for alfalfa and tall fescue; a single equation for each waveband and canopy/sky condition sufficed to describe the average transmittance. Canopy structure, LAI, and, to a lesser degree, the extent of direct and diffuse radiant energy were found to influence penetration more than sun angle. An envelope of transmittances defined by equations representing the maximum and minimum light transmittance illustrates the variability in transmittances and was broadest under clear skies and narrowed with decreasing wavelength. Leaf area altered the average ratios of above-canopy UV-B/UV-A and UV-B/PAR ratios. The average ratios of above-canopy UV-B/UV-A and UV-B/PAR ratios varied slightly with year and sky conditions. Differences between the two canopies indicate the need to consider canopy architecture in determining the amount of light penetrating a canopy in the UV-B, UV-A and PAR." |
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| Language: | English |
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| References: | 42 |
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| Note: | Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Shulski, Martha D., Elizabeth A. Walter-Shea, G. Y. Yuen, G. Horst, and KEnneth G. Hubbard. 2004. Penetration of photosynthetically active and untraviolet radiation into alfalfa and tall fescue canopies. Agron. J. 96(6):p. 1562-1571. |
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| Web URL(s):
https://dl.sciencesocieties.org/publications/aj/articles/96/6/1562
Last checked: 11/02/2016
Access conditions: Item is within a imited-access website |
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MSU catalog number: S 22 .A45 |
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