Adubação fosfatada na implantação de sistema silvipastoril com eucalipto e capim mombaça em neossolo quartzarênico no ecótono Amazônia/Cerrado

Abstract

The search for alternatives to intensify the production of cattle the pasture and reduce areas of pasture degradation has been the focus of national livestock. Among the causes of the degradation of these areas we can mention inadequate management and reduced soil fertility, especially in phosphorus. The objective of this work was to evaluate the phosphorus fertilization on the morphogenesis, structural, productive, bromatological and rhizosphere Mombasa in the year of implementation and in the following year of a Silvipastoral system with Eucalyptus and monoculture of Mombasa grass in Quartzarenic Neossol. The experiment was conducted in the rainy seasons,agricultural years 2016/2017 and 2017/2018, in the test area was divided into two cropping systems: Mombaça grass (0.25 ha) and Silvipastoril in a eucalyptus and grass intercrop (0.75 ha).The experimental design was completely randomized in a 4 x 2 factorial scheme, with four doses of phosphorus (0, 50, 100, 200 kg of P2O5 ha-1 year-1) and two cultivation systems (monoculture and silvopastoral), with three replications.Three cycles were evaluated in the rainy season, with an average rest period of 21 days. The morphogenic and structural characteristics were: leaf appearance rate, leaf elongation rate, phyllochron, stem elongation rate, leaf area index, tillers population density, crop growth rate, leaf life days and leaf / stem ratio. The productive, nutritional characteristics and root evaluation were: total dry mass (kg. ha-1), leaf dry mass (kg.ha-1), culm dry mass (kg. ha-1), dry matter dry mass (kg.ha- 1); dry matter, mineral matter, organic matter crude protein, neutral detergent fiber and acid, root dry mass), root to shoot ratio, mycorrhizal colonization (%). In general, factors tested such as phosphate fertilizer,cultivation system and driving year (implementation and following year) showed influence, altering the development of Mombaça grass, reflecting on the morphogenic, structural and productive characteristics and colonization by mycorrhizal fungi, increasing crop growth rate, leaf appearance rate, leaf elongation rate, stem, total dry mass, leaf dry mass, stem dry mass and mycorrhizal fungi colonization. Phosphate fertilization did not alter bromatological characteristics of Mombasa grass during system implementation phase silvipastoral and monoculture.Phosphorus applied in planting is important for forage development and establishment, and therefore for the maintenance of grass over the years, however, there are peculiarities to be analyzedfor the effective dose of phosphate fertilizers for Mombasa gras in its different variables,seeking to reduce the inefficiency of phosphate fertilizer in Quartzarenic neosol for Mombasa grass, allowing the reduction of fertilizer use and production costs.