Efeito do Fertilizante Amoniacal e da granulação na solubilização do fosfato reativo bayóvar

• Ano de defesa: 2014
• Autor(a) principal: Valadares, Rafael Vasconcelos
• Orientador(a): Cantarutti, Reinaldo Bertola
• Banca de defesa: Vieira, Rogério Faria , Oliveira, Teógenes Senna de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Solos e Nutrição de Plantas
• Departamento: Fertilidade do solo e nutrição de plantas; Gênese, Morfologia e Classificação, Mineralogia, Química,
• País: BR
• Palavras-chave em Português: Fertilizantes nitrogenados; Nitrogênio; Fósforo
• Palavras-chave em Inglês: Nitrogen fertilizers; Nitrogen; Match
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5541

Ammoniacal fertilizer may favor the P solubilization from reactive phosphates (RP) due to chemical and nutritional effects in the soil-plant system. For mixtures with RP, the solubilization efficiency depends on factors such as the nitrogen source, the physical mixture form and the content of N in the fertilizer, among other factors. Thus, the objective of this work was to evaluate the effect of nitrogen fertilizers and mixtures forms on phosphate dissolution and on phosphorus (P) available. The experiment was carried out in Soil Department s greenhouse of Federal University of Viçosa-MG, Brazil, for 42 days. Each plot consisted of a pot with 3 dm3 of a heavy clay soil and three maize plants. The treatments consisted of mixtures of the Bayóvar reactive phosphate (By) with three nitrogen sources [urea (U), ammonium sulfate (AS) or potassium nitrate (NK)], in two physical mixtures forms (powder or granulated) and in two molar N:P proportions (1:1 or 0.5:1). It was also evaluated four additional treatments (without fertilization with P; MAP; powder By; granulated By). Resulting, therefore, in a 1 + 1 + 2 + (3 x 2 x 2) factorial scheme. The experiment was arranged in the randomized blocks design with four replicates. The fertilizer dose was estimated based on the P-rem value and the application was done in a localized manner. The ammoniacal fertilizers caused higher dissolution from phosphate, regardless of the form of mixture. Combinations with ammonium sulfate conditioned higher roots growth than pure By, By in mixtures with potassium nitrate or urea. It has also been found that mixtures of powdered BySA or granulated ByNK (ratio of 1:1) led to higher values of P acquisition than ByU or By, demonstrating the importance of the chemical effect of pH reduction on the dissolution, determined by the presence of N-NH4, and of the nutritional effect of the presence of N-NO3. In short, the mixture with N sources increased availability of P from By, even in unfavorable conditions for dissolution, especially in combination with BySA in 0,5:1 molar relation. Plants fertilized with MAP showed higher growth and nutrient uptake than plants fertilized with By or By in mixtures with N.