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Influence of Soybean Pubescence Type on Radiation Balance 1
Author(s) -
Nielsen D. C.,
Blad B. L.,
Verma S. B.,
Rosenberg N. J.,
Specht J. E.
Publication year - 1984
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1984.00021962007600060015x
Subject(s) - canopy , photosynthetically active radiation , cultivar , albedo (alchemy) , agronomy , evapotranspiration , earth's energy budget , environmental science , horticulture , photosynthesis , radiation , atmospheric sciences , botany , biology , physics , art , ecology , quantum mechanics , performance art , art history
Increasing the density of pubescence on the leaves and stems of soybeans ( Glycine max L.) should influence the radiation balance of the soybean canopy and affect the evapotranspiration and photosynthetic rates. This study was undertaken to evaluate the influence of increased pubescence density on various components of the radiation balance. Near‐isogenic lines of two soybean cultivars (Clark and Harosoy) were grown in four adjacent small plots (18 ✕ 18 m) during the 1980, 1981, and 1982 growing seasons near Mead, Nebr. The soil at this site is classified as a Typic Argiudoll. The isolines of each cultivar varied only in the amount of pubescence (dense vs. normal pubescence). Measurements of albedo, reflected photosynthetically active radiation (PAR), emitted longwave radiation, and net radiation were made over the crop surfaces with instruments mounted on a rotating boom located at the intersection of the four plots. Radiative canopy temperatures were measured with a handheld infrared thermometer (IRT). Results show that dense pubescence increased reflection of shortwave radiation and PAR by 3 to 5% and 8 to 11%, respectively. Emitted longwave radiation and radiative canopy temperature were not significantly affected by increased pubescence, although there was a slight tendency for the dense pubescent canopy to be cooler. Increased pubescence decreased net radiation over the canopy by 0.5 to 1.5%. These results suggest that soybeans with dense pubescence may be slightly better adapted to the high radiation, high temperature, and limited moisture conditions of the eastern Great Plains than are those with normal pubescence.