Production Characteristics of Ryegrass Pasture under Different Intensities of Grazing and Nitrogen Fertilization in Integrated Crop-livestock Systems

Abstract

Background: There is little information on the effect of interaction between grazing intensity and nitrogen fertilization on the productive characteristics of ryegrass (Lolium multiflorum Lam). The objective of this work was to evaluate the effect of grazing intensity and nitrogen fertilization on the productive characteristics of ryegrass pasture in a crop-livestock integration system. Methods: A randomized complete block experimental design with a 2x2x5 factorial arrangement was used, with three replications. The study factors were two management grass heights, low height (LH=10 cm) and high height (HH = 25 cm), two different nitrogen fertilization times (NP = nitrogen applied to pasture and NG = nitrogen applied to grains crop) and five evaluation periods. Result: The forage mass was higher at higher handling heights and with lower stocking rate (HH = 3995 kg DM ha-1). The forage density tended to be higher in the plots with lower grass height and nitrogen fertilization (LH = 193.5 and NP = 184.7 kg DM ha-1 cm-1). The highest accumulation rate (AR) and forage production (FP) was observed in managed pastures with HHNP (AR = 120.4 kg DM ha-1day-1; FP = 18471 kg DM ha-1). The management of grass with HHNP provided higher forage mass, higher accumulation rate and higher dry matter production in ryegrass pasture, due to an adequate stocking rate.