A intensificação de sistemas agropecuários em região de altitude a partir do pastejo bovino e do consórcio de milho com capim aruana

Abstract

The main objective of this research was evaluating the possibility of intensifying food production in high-altitude regions from animal grazing managed under different heights that maximize feed ingestion per unit of time, and including aruana grass preceding corn as the source of animal feed during the time winter pastures are established. The experiment was conducted at Guarapuava/PR, at Fazenda Capão Redondo, located on the Terceiro Planalto Paranaense highlands, (-25.39278° W, -51.84575° S), 1006 m.a.s.l. with a Cfb climate (Köppen). The soil is classed as oxysol associated with cambisols. The research was conducted in 5 phases: Pasture 1, Corn Grain, Pasture 2, Pasture 3 and Soybean. The experimental design warandomized blocks with four replicates and two treatments on the phase Pasture 1 and three treatments on the following phases. Treatments on the first phase were: [a] SIPA: characterized by a system with winter grazing, receiving nitrogen fertilization [b] SA: characterized as a system with no winter grazing, receiving nitrogen fertilization. On the phases Corn Grain, Soybean, Pasture 2 and Pasture 3, in addition to the described treatments, a new treatment was added (SIPAaruana) by sowing on the interrows of corn, of Megathyrsus maximum cv Aruana. On those plots, autumn grazing was conducted on the aruana grass and winter grazing on the following crop. The evaluations on the phase Corn Grain were plantability, yield components and yield per hectare, on the phase Soybean, yield components and yield per hectare, and on the phases Pasture 1; 2 and 3, parameters related to canopy structure and chemical aspects, biomass and animal weight gain. The treatments were not different (P>0.05) on Corn Grain and Soybean yield. Animal grazing modifies the canopy structure, stratifies pasture height and induces a higher system biomass yield. No differences were found for Corn plantability on the different production systems. Intersown corn and aruana grass had no effect on the corn yield components. Aruana grass yielded 8083 kg MS ha and presents itself as an alternative to provide forage during winter pastures establishment. Animal grazing and the inclusion of aruana grass in the system increased the biomass yield and modified the cycled nutrients concentration in the system.