Biochar : matriz orgânica para fertilizantes organominerais e aditivo zootécnico

Abstract

The growing world population makes increasing demands on agricultural systems to ensure food security, by the use of soils with overexploitation of natural resources and excessive application of fertilizers. Amidst this scenario are the anthropic emissions of greenhouse gases (GHG) that contribute to the worsening of global warming issues. To promote the sustainability of agricultural production, it is imperative to develop more economically competitive productive models with GHG mitigation strategies. Thus, the use of slow-release fertilizers in agricultural production, as well as the use of additives in ruminant diets to manipulate rumen fermentation, can serve as GHG mitigation strategies for more efficient systems. In this context, biochar, a carbonaceous material from pyrolysed biomass, with characteristics that can act to improve soil fertility and also reduce GHG emissions, has been widely investigated. Our hypothesis for this work, regarding the use of biochar, has two aspects: i. the application of organo-mineral nitrogen fertilizers based on biochar alters the dynamics of N in the soil and the emissions of nitrous oxide (N₂O) to the atmosphere; ii. the use of biochar can modify the characteristics of rumen fermentation and result in a decrease in the production of CH₄. Thus, the objective with this study was to evaluate the potential of biochar in GHG mitigation. In Chapter 1, biochar was pelleted with urea to produce different organo-mineral nitrogen fertilizers, in order to minimize N losses in nitrate (NO₃⁻) and ammonium (NH₄⁺) leaching, as well as N₂O emissions. In Chapter 2, biochar was added at different levels in diets formulated for finishing beef cattle on tropical grass pasture in the dry season on rumen fermentation parameters and CH₄ production.