Características químicas e microbiológicas do solo em pastagem de Brachiaria decumbens após a implantação de leguminosas forrageiras

• Ano de defesa: 2011
• Autor(a) principal: VICENTIN, Rayssa Pereira
• Orientador(a): LIRA JUNIOR, Mario de Andrade
• Banca de defesa: FREITAS, Ana Dolores Santiago, BIONDI , Caroline Miranda, Dubeux, José Carlos Batista
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural de Pernambuco
• Programa de Pós-Graduação: Programa de Pós-Graduação em Ciência do Solo
• Departamento: Departamento de Agronomia
• País: Brasil
• Palavras-chave em Português: Solos; Brachiaria decumbens; Microbiologia do solo; Leguminosa forrageira; Fertilidade do solo
• Palavras-chave em Inglês: Soil; Forage legumes; Soil fertility; Soil microbiology
• Área do conhecimento CNPq: AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5330

Extensive grazing is the main Brazilian meat production system. Usually pasture yield soon after implantation is high, but it declines after a few years of exploration, showing degradation signs. Nitrogen is one of the most important nutrients on degradation, due to both high costs of fertilization and nutrient loss by the system. An alternative to nitrogen fertilization is the use of forage legumes, which fix nitrogen due to their symbiosis with rhizobia, and which have a lower C/N ratio. Considering the potential use of legumes in pastures, this work aims to evaluate the effect of forage legume implantation in degraded Brachiaria decumbens pasture on soil fertility and microbiology. To this end, 540 m² plots are being cultivated with Arachis pintoi Krap & Greg cv Amarillo, Clitoria ternatea L., Calopogonium mucunoides Desv and Campo Grandes Stylosanthes, which is a 80:20 weight basis mix of Stylosanthes capitata and S. macrocephala intercalated with B. decumbens lines, as well as two brachiaria only treatments, with and without nitrogen fertilizer, totaling six treatments. pH, Al3+, Ca2+, Mg2+, K+, P, sum of basis (SB) and aluminum saturation (m) were evaluated at 0-10, 10-20 and 20-40 depths, and soil microbial biomass carbon (C-BMS) and nitrogen (N-BMS), soil basal respiration (RBS), metabolic quoficient (qCO2), and carbon and nitrogen ratio of the microbial biomass (C/N) at the 0-10 cm depth. Sampling was on a transect parallel to plot length, representing legume and grass strips. Legume strips had lower soil basal respiration, pH, sum of basis, Ca2+ and Mg2+ while Al3+ and aluminum saturation increased. Calcium increased in comparison to the values before the experiment. Changes in soil fertility due to legumes must be considered for soil correction and fertilization recommendations.