Studies on the Competition between Grass and Legume in the Mixed Sward : IV. Influence of the light intensity on the growth of orchardgrass and Ladino clover grown in mixtures in the same sward

Abstract

The author tested the influence of the mutual shading on the growth of orchardgrass and Ladino clover grown in mixtures in the same sward. For that purpose, both species were grown in pure and mixed sward, and three cutting plots were set up in two swards respectively: three cutting plots in mixed sward were provided a range from extream grass dominance to extream clover dominance. Yield and plant density were measured in pure and mixed sward. And botanical composition, leaf area index and light intensity were measured at 10 cm vertical intervals in each plots of mixed sward at each harvests. The following results were obtained. 1) Long cutting interval gave increased plant height of orchardgrass at any seasons. Under conditions of increased plant height of orchardgrass and consequent low light intensity at the clover canopy, the growth of clover not only become slow but eventually was strongly negative, leading to a marked reduction in both the stolon number and the yield of clover. 2) Short cutting interval gave increased plant height of clover relatively during summer and autumn. Under conditions of increased plant height of clover and consequent low light intensity at orchardgrass surface, the growth of grass not only become slow but evtentually was strongly negative, leading to a marked reduction in both the hill number and the yield of orchardgrass.