Abstract
Canopy structure and light extinction within the canopy were investigated in bahiagrass (Paspalum notatum Flugge) swards subjected to different cutting heights, i.e. 2 (LL), 7 (L), 12 (M), 17 (H) and 22 (HH) cm above ground level. Swards under lower cutting heights were always more leafy and greener with less dead material. Extensive accumulation of dead material in M, H and HH swards modified light extinction within the canopy, due to absorption of radiation by dead material. In May, swards subjected to lower cutting heights showed higher leaf densities, with a greater part of leaves being distributed above non-photosynthetic organs, and less declines in radiation flux density with increased cumulative leaf area index. These canopy characteristics of severely defoliated swards in early growing season are considered to contribute to high tolerance of bahiagrass to close defoliation, through high light utilization efficiency for plant production. The results also imply that maintaining a bahiagrass sward short in winter to mid-spring (December-April) by closely defoliating the sward in autumn is an important sward management strategy leading to high quantity and quality of herbage and high tiller densities in early growing season.
