Renovação de pastagem em plantio direto e sistema agrossilvipastoril

• Autor(a) principal: Santos, Márcia Vitória
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1738
• topic: Pastagem degradada; Cultivos múltiplos; Sustentabilidade; Degraded pastures; Multiple cropping; Sustainability; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PASTAGEM E FORRAGICULTURA

Minas Gerais Forest Area is characterized by the presence of small farms, having as one of its main activities the dairy farming, maintained, mostly by handlabor family. In its properties the situation of pastures is not very different from that observed in the country. Thus, degraded pastures are common with low yield potential, low bearing capacity and low production of meat and milk. Given the importance of finding alternatives for the restoration and renovation of degraded pastures in the region of Minas Gerais Foresta Area, as well as for the rest of the country, and the need to know the real potential of agroforestry systems in the renovation of these areas were performed four experiments to assess: the phytosociological survey of a degraded pasture of Melinis minutiflora (molasses grass), before the introduction of agrossilvipastoril system , the production of corn due to arrangements of species intercropped with maize (fodder Brachiaria, eucalyptus and acacia) in agrossilvipastoril system compared to their monocultures and two weed management, the effect of nicosulfuron on productivity and quality of corn silage, and growth of eucalypt and acacia when grown intercropped with maize and forage in Brachiaria agrossilvipastoril system, as well as animal behavior on the tree species, one year after implantation. The experiments were conducted in degraded pasture grass (Melinis minutiflora), located on the campus of Federal University of Viçosa - MG. We tested three species of forage plants intercropped with maize or corn and eucalyptus + eucalyptus and acacia: Brachiaria brizantha cv. Marandu, B. decumbens cv. Basilisk and B. brizantha cv. Piatã. In addition, two systems were evaluated for weed management in corn: 1.5 kg.ha-1 of atrazine and 1.5 kg.ha-1 of atrazine + 0.006 kg.ha-1 of nicosulfuron. Prior to renovation, there was the phytosociological survey of pasture, as a way of measuring the weed infestation. For renewal of grazing, the sowing of maize and fodder were held in December 2007 in no-tillage system. The spacing of maize was 0.8 m between rows and 0.4 m of fodder, which are sown in line and between the maize, respecting 1.5 m away from woody plants, intercropped plots. The seedlings clone 3336 Eucalyptus grandis x E. urophylla (eucalyptus), and Acacia mangium (Acacia) were planted at the same time sowing of maize and forage plants, in holes of 0.40 x 0.40 x 0.40 m in the spacing 12 x 2 m plots intercropped. The Acacia seedlings were planted alternating the eucalyptus trees in rows. Eucalyptus was also planted in monoculture in spacing 3 x 2 m. The effect of nicosulfuron was evaluated for corn yield and grain quality and yield of corn for silage. Corn silage was harvested at 105 days after sowing. The characteristics of corn grain yield were obtained at the time of harvest at 130 days after sowing. The formation and establishment of the pastures were measured up to a year of implementation of systems, as well as the development of tree species. The phytosociological study concluded that the grass had high infestation by weeds, including species that are considered toxic, spiny and highly competitive with the fodder needed to be renewed. The application of nicosulfuron and atrazine mixture reflected in increased plant height of corn and ear, without affecting the productivity of maize grain. The eucalyptus, acacia and species of Brachiaria do not influence the yield of corn for grain and silage. The nicosulfuron does not promote significant increase in productivity and quality of corn silage. Although the yield of corn and corn silage produced in agrossilvipastoril systems is less productive than the monoculture of corn, due to a reduction of 25% of the area for the tree component, the producer is paid in profitability with eucalyptus and acacia, as well as pasture renewed. At 60 days after maize harvest, the pastures have good establishment, however, the entry of cattle grazing is limited by the development of the tree components. In relation to the tree component, it is concluded that the growth of eucalyptus and acacia is not influenced by intercropping with maize and fodder, and if the planting of eucalyptus and acacia is the growth of acacia, which would determine the timing of entry of animals in the pasture. In this study, one year after the arboreal species planting, the pasture by bovines of medium weight of 250 Kg didn't cause damages to the plants. Although the volume of wood per hectare produced in agrossilvipastoril systems is less than the monoculture of eucalyptus, the producer is paid in the profitability of corn and forage for meat and milk.