Dependence of Solar Radiation Transport in Rice Canopies on Developmental Stage

Japan Agricultural Research Quarterly
ISSN 00213551
NII recode ID (NCID) AA0068709X
Full text
41-01-06.pdf792.14 KB

Solar radiation in a rice canopy plays an important role in the energy balance on both the plant leaves and soil/water surface. A simple model was derived from the two-stream model to estimate two important factors characterizing radiation in a plant canopy, namely, transmissivity of the canopy (τc ) and the albedo of the canopy (ref), from the absorption coefficient of leaves (α) and leaf inclination factor (F). To clarify the seasonal variation in α and F with growth, season-long observations were conducted in paddy fields during three different cropping seasons. Values of α were almost constant throughout the growing period; however, values of F tended to increase with growth. Values of F were larger than 0.5 (the theoretical value for random leaf distribution) in the late growth stage mainly due to the alterations in leaf geometry with the change in leaf inclination angle along a more horizontal axis after flowering, while in contrast, values of F were less than 0.5 in the early growth stage mainly due to the distribution bias of leaves after transplanting. Seasonal variation in F during different cropping seasons could commonly be expressed as a function of developmental stage (DVS). Using this function, τc and ref could be estimated with more accuracy. The proposed radiation model and function is expected to be applicable in more accurate evaluation of solar radiation, dry matter production and soil/water temperature in paddy fields.

Date of issued
Creator MARUYAMA Atsushi KUWAGATA Tsuneo OHBA Kazuhiko MAKI Taichi
Subject

absorption coefficient

albedo

inclination factor

paddy field

Publisher Japan International Research Center for Agricultural Sciences
Available Online
NII resource type vocabulary Journal Article
Volume 41
Issue 1
spage 39
epage 45
DOI 10.6090/jarq.41.39
Rights Japan International Research Center for Agricultural Sciences
Language eng

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