Productive implications in grazing under high severity defoliations in Italian ryegrass managed under intermittent stocking method

Abstract

Grazing management has as one of the main objectives the vigorous regrowth, since the remaining leaf area has a high correlation with the regrowth potential of pastures. Thus, the objective of the present work was to evaluate the effect of high severity punctual interventions (70%) on productive characteristics of Italian ryegrass pastures managed under intermittent stocking method. The experiment was conducted in the experimental area of ​​the Federal Technological University of Paraná. The treatments consisted of four defoliation strategies from a single entry height (20cm): constant severity 40%; severity of 40% with punctual interventions of 70% in the second; severity of 40% with punctual interventions of 70% in the fourth cut; and severities of 40% and 70% interspersed. The treatments were applied in a completely randomized design with three replications, totaling 12 experimental units. It was evaluated: solar radiation interception, forage production and morphogenic characteristics (leaf appearance rate, phyllochron, leaf elongation rate and leaf senescence rate). The pre-defoliation solar radiation interception did not differ between treatments, only in the post-defoliation situation. For morphogenic characteristics, treatments with high defoliation severity presented the highest values. Forage production did not differ between treatments. Within the conditions applied in the present study (i.e. pre-cut height), punctual interventions of high severity (70%) do not affect the productive capacity of Italian ryegrass.