Defoliation intensity and leaf area index recovery in defoliated swards: implications for forage accumulation

This study evaluated the leaf area index (LAI) recovery mechanisms and forage accumulation rates on regrowth of different grass species subjected to defoliation intensities. For that purpose, plots Pennisetum clandestinum (kikuyugrass), Lolium multiflorum (annual ryegrass), Avena strigosa (black oats) were defoliated from 20 80 % their initial heights (25, 20, 25 cm, respectively). At increments in height, samples collected ground level used estimate tiller population density (TPD), per (LA), mass. From these data, we calculated (LAI), average (aLAI), instantaneous rate (FAR IFAR, Data plotted over time (days) describe LAI rates. As intensity increased, greater canopy needed for pastures achieve maximum rates, which required longer intervals. The need high recruitment after defoliation, delayed recovery, seemed be one main cause. Thus, grazing management strategies involve costly could decrease both overall production sward persistence time. However, plant ability recover successive intense defoliations seems species-dependent related phenotypic plasticity.