The interception and absorption of radiation in plant stands.
Expressions are presented for the penetration of direct and diffuse radiation into stands having (a) horizontal leaves, (b) randomly oriented leaves, and (c) vertical leaves randomly oriented in the horizontal plane, with equations for the radiation exchanges due to scattering and reflection by the leaves. Flux density profiles for visible, near infra-red and long-wave radiation were computed for a stand with horizontal leaves, appropriate optical properties of the leaves being assumed for each waveband. The net flux density due to radiation of all wavelengths was calculated for a given spectral distribution of the radiation above the stand. The absorption profile of radiation of all wavelengths was very similar to that of visible radiation; reasons for this are examined.-F. A.S.