PSIV-B-27 Late-Breaking: Effects of grazing management and nitrogen fertilization on Marandu palisade grass production in silvopastoral systems

Abstract

Integrated systems have been gaining prominence in recent years, especially the crop-livestock-forestry, which, in addition to being an alternative income per area, increase fertility and organic matter content in the soil, and protect animals against weather conditions. However, there is still a lack of knowledge about the management of pastures under such conditions. Therefore, the aim of this research was to evaluate the grazing management and nitrogen fertilization in Marandu palisade grass consorted with Eucalyptus to obtain the greater of forage production. The experimental design was a randomized block, arranged in split-plot, the plots were composed of two eucalyptus spacing (12 x 2 or 12 x 3) and Marandu monoculture, the subplots were composed of the nitrogen fertilization rate (0, 100, 200 kg N/ha using ammonium sulfate). The higher DM accumulation rate was observed at 200 kg N ha-1 (69.29 kg DM ha-1 day), while there was no difference between the treatments without fertilization and 100 kg N ha-1 (P > 0.001). DM accumulation rate increased by 30.01% when fertilization increased from 100 kg N ha-1 to 200 kg N ha-1. Marandu palisade grass with 200 kg N ha-1 showed the highest production (28.82 t ha-1) independent of spacing. In the silvopastoral system, the greater accumulation of forage was observed when handled with 80% of the light interception (LI), corresponding to a height of 67 cm. Therefore, we conclude that Marandu grass in a silvopastoral system, without N fertilization, should be managed with a pre-grazing height of 60 cm and 73% LI. Marandu grass in a silvopastoral system, with 100 kg N ha-1 fertilization, should be managed with a height of 68 cm and 84% LI, and, with 200 kg N ha-1, should be managed at 80% of LI for the greater pasture utilization and development.