The influence of leaf area and radiation on the growth of clover in swards

Abstract

A study was made of the light regime and the growth of clover: (a) in mixed swards with varying proportions of grass; (b) in specially designed cultures in which grass and clover competed for light alone.

The growth of the clover showed direct dependence on the level of radiation at the surface of the clover leaf canopy; it was positive when radiation values were above about 60–80 cal/cm²/day but fell to zero or negative rates at lower radiation levels.

A relationship is presented between the level of radiation, the leaf area index, and the crop growth rate. It is shown that the optimum leaf area index increases with increasing levels of radiation; and further that as the leaf area index increases, the level of radiation required for maximum growth rate also rises. The implications in agricultural practice are discussed briefly.