| Abstract: | This research addressed the influence of defoliation intervals and cutting height on the productive capacity and quality, trend of carbohydrate reserves, and the rate of regrowth in relation to leaf area and light interception on twelve warm-season grasses. Twelve warm-season perennial grasses were defoliated at two frequencies (21- and 42-day) and at cutting heights of 10- and 30-cm. The response patterns exhibited by the twelve grasses indicated that Pretoria-90, Verde kleingrass, Klein-75, Llano and Nueces buffelgrass, and Old world bluestem were the most important grasses in this study in terms of forage yield, digestibility and regrowth characteristics. Forage yield, crown weight, tiller number, growth rate, live-dead tiller ratio, light interception, leaf area index, non-structural carbohydrates, and residual leaf area for the twelve grasses were highest at the 42-day harvest frequency and 30 cm cutting height. Leaf-stem ratio and in vitro dry matter digestibility exhibited the highest values at a frequency of 21 days and 30 cm cutting height. IVDDM declines with age and season, recovering at the end of the growth season. Defoliation at the 21-day harvest frequency with 10 cm cutting height significantly suppressed crown development, tillering, and nonstructural carbohydrate concentration in all grasses and resulted in significant reductions in forage yield. Clipping at the 42-day harvest frequency with 30 cm cutting height allowed for increases in growth rates, energy reserves, and tiller number production. Light interception and growth rate showed quadratic relationships with leaf area index. The relationship between growth rate and dry matter production with leaf area residual, non-structural carbohydrates, and tiller number were not consistent. |
|---|