A theoretical analysis of nitrogen and radiation effects on radiation use efficiency in peanut [Arachis hypogaea]
1994
Hammer, G.L. (Queensland Dept. of Primary Industries, Toowoomba (Australia)) | Wright, G.C. (Queensland Dept. of Primary Industries, Kingaroy (Australia))
A theoretical framework was developed to determine photosynthesis of a layered crop canopy by distributing incident radiation among sunlit and shaded leaves in each layer. It allows for variation in incident direct and diffuse radiation associated with location (latitude), time of year, time of day, and atmospheric condition, which is expressed as the degree of transmission of extra-terrestrial radiation. It also allows for variation in photosynthetic capacity associated with average specific leaf N of the canopy and its distribution in the canopy. Daily canopy photosynthesis, intercepted radiation, and radiation use efficiency (RUE) are obtained by numerical integration of instantaneous values calculated at specific times of the day. The framework predicted experimentally determined RUE values accurately and quantified the contribution of each major factor to variation in RUE. The major cause of previous underestimation of RUE was found to be variation in RUE associated with the level of incident radiation flux density as affected by the degree of atmospheric transmission.
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