The objective this study was to evaluate the growth rates of Tifton 85 bermudagrass under four nitrogen levels (0, 33, 66, 100, and 133 kg/ha N) and harvested at three plant heights (30, 40 and 50 cm). The experimental design was completely randomized in a split plot scheme with three replications. Nitrogen rates were set in the plots and plants heights in the subplots. For all variables, the interaction N rate × plant height was not significant. The net assimilatory rate and relative growth rate of Tifton 85 increased with increasing N rates. The leaf area ratio (LAR) decreased linearly with plant height at harvesting. In contrast, the LAR increased linearly with N rate. Linearly, the leaf weight ratio decreased with plant height at harvesting, and increased with N rate. The specific leaf area of Tifton 85 bermudagrass was influenced linear and positively only by nitrogen fertilization. The leaf area index (LAI) of Tifton 85 bermudagrass increased by about 0.05 unit for each centimeter increase in plant height at harvesting. There was a quadratic response of N in LAI of Tifton 85 bermudagrass. The increase of bermudagrass height at harvesting season decreases the participation of leaf blade in the forage. The nitrogen increases the growth rate of Tifton 85 bermudagrass. To ensure efficient harvesting of forage, the increase of N rate for Tifton 85 Bermudagrass implies a reduction in the harvest interval.
Cynodon; frequency cut; leaf area index; leaf blade
