Spatial and Temporal Variation in the Distribution of Radiation in a Mature Corn Canopy

Abstract

<p>A study of the spatial and temporal variability of global solar, net solar and net radiation in two plots of corn, seeded differently, was undertaken using a moving tramway sampling system. Horizontal frequency distributions of radiant flux density revealed a systematic variation dependent on canopy structure.</p> <p>A modified exponential model was developed as an empirical solution to the problem of estimating radiation fluxes in plant canopies. Since the extinction coefficients are dependent on present data its validity must await independent evaluation by other workers.</p> <p>SOLCOMP, a simple layer model for global and net solar radiation was developed from theoretical considerations. This model performed well and illustrates that it is possible to model the radiation regime in a crop with a simple, theoretically-based construct using a small number of easily obtained input parameters. A further development, NETCOMP, suitable for estimating net radiation in the canopy showed potential but could not be fully tested due to lack of information on canopy temperature regimes.</p>