Navegando por Autor "SILVA JUNIOR, Alberto Cruz da"

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Acesso aberto (Open Access)
Influência da variação sazonal de atributos de fertilidade do solo sobre a biomassa microbiana em uma cronosseqüencia de plantio de palma de óleo (Elaeis oleifera (Kunth) Cortés) no Nordeste Paraense
(Universidade Federal do Pará, 2013-02-19) SILVA JUNIOR, Alberto Cruz da; RUIVO, Maria de Lourdes Pinheiro; http://lattes.cnpq.br/9419564604488031
Brazil has about 32 million hectares of areas with capability to oil palm’s expansion and more than 90% of these are in the Amazon. There is need to understand the interaction of new plantations and its development with the environment. This study was conducted in Dende do Pará SA (DENPASA), commercial plantations company, and aimed to evaluate precipitation’s seasonal variation on the soil fertility and thus on soil biomass in a chronosequence of oil palm plantations with 5, 8 and 12 years and secondary forestry. We measured / estimated and correlated the attributes carbon microbial biomass (CSMB), total carbon (CTOTAL), total nitrogen (NTOTAL), soil basal respiration (SBR), metabolic quotient (qCO2), carbon microbial biomass / total carbon ratio (CBMS: CTOTAL), carbon / nitrogen ratio (C / N), gravimetric moisture (Ug), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), effective exchange capacity of cations (CTC) and aluminum saturation (m). The CBMS was the attribute most sensitive to differentiate areas of study and dry and rainy seasons. Chemical characteristics of soil fertility and soil microbial biomass were correlated stronger and in greater numbers during the rainy season. Chemical attributes of soil fertility and soil microbial biomass presented correlation more strong and in greater numbers during the rainy season. The microbial indices qCO2 and CBMS:CTOTAL proved that conventional planting areas can be relatively efficient in relation to C dynamics compared to secondary forest area.
Acesso aberto (Open Access)
Variação temporal do efluxo de CO2do solo em sistemas agroflorestais com palma de óleo na Amazônia Oriental
(Instituto Nacional de Pesquisas da Amazônia, 2016-03) SILVA, Carolina Melo da; VASCONCELOS, Steel Silva; OLIVEIRA JUNIOR, Moisés Cordeiro Mourão de; KATO, Osvaldo Ryohei; SILVA JUNIOR, Alberto Cruz da; CASTELLANI, Débora Cristina
The soil carbon dioxide (CO2) efflux dynamics and its controlling factors of Amazonian agroforestry systems are poorly understood. The objective of this study was to evaluate the temporal variation of soil CO2 efflux in oil palm-based agroforestry systems and the relation between efflux and biotic (microbial and total soil carbon, microbial respiration, fine roots, individual components of agroforestry systems (AFS)) and abiotic factors (soil moisture and temperature). The measurements were taken during the less rainy (December 2010) and rainy (May 2011) periods. The soil CO2 efflux was highest during the rainy season, probably due to increased microbial activity influenced by climatic factors coupled with biotic factors. The soil CO2 efflux correlated positively with soil moisture and microbial biomass carbon and negatively with soil temperature and metabolic quotient, but these correlations were weak. The soil CO2 efflux was sensitive to the type of agroforestry system and to rainfall seasonality.