Observed and calculated photosynthetic rates of Chloris gayana communities.
Abstract
Photosynthetic rates of C. gayana communities were calculated using mathematical models relating the photosynthetic contribution of the leaves to direct and diffuse radiation and to the distribution pattern of the foliage, by means of photosynthetic response functions. The calculations were found to agree with photosynthetic rates measured gasometrically with a portable field chamber. Communities with LAI > 2.5 could be adequately represented by a single continuous horizontal foliage layer. In a general model, appropriate to all communities and capable of accepting multiple photo-synthetic response data, a consideration of alternative strategies indicated that leaf angle need only be specified in terms of the mean angle per leaf layer, though there was a suggestion in some of the data that the incorporation of leaf angle distribution improves the accuracy of the mathematical approach in some situations.-R.B.