IG - Instituto de Geociências

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2172

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Navegando IG - Instituto de Geociências por Assunto "Agricultura familiar"

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    Ictiofauna de igarapés de pequenas bacias de drenagem em área agrícola do Nordeste Paraense, Amazônia Oriental
    (Universidade Federal do Pará, 2012-06) CORRÊA, Jean Michel; GERHARD, Pedro; FIGUEIREDO, Ricardo de Oliveira
    Stream fish communities can show spatial and temporal patterns, which can be revealed by species association or species groups as well as by species preference to certain habitats. The reduced number of studies and the scarce knowledge on the aquatic fauna in the Amazon results on an under-estimative upon stream fish fauna diversity. In this study, a survey at three small Amazonian catchments located in family agriculture areas, a total of 2,117 individuals were collected, belonging to seven orders, 13 families, 27 genera and 43 species. The most abundant species in all samples was Hyphessobrycon heterorhabdus, totaling 337 individuals, followed by Bryconops melanurus, with 326 individuals. The species richness was highest in a Pachibá stream reach, with 21 species. Simpson’s diversity index in a Cumaru stream reach showed the highest species dominance with a value of 0.43, while Shannon’s diversity index showed that the Pachibá stream lowest reach, had the greatest diversity with a value of 2.39. Iguanodectes rachovii was the most constant species, occurring in 50% of samples. Therefore, as a response to habitat size, the intermediate stream reaches presented the highest species diversity. Our study showed that agricultural catchments dominated by smallholder farmers can bear a reasonable stream fish diversity.
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    O programa PROAMBIENTE na Transamazônica: lições aprendidas
    (2013-06) ALMEIDA, Everaldo Nascimento de; XIMENES, Tereza Ferreira; JORGE, Yared; BRIENZA JÚNIOR, Silvio; POÇA, Raquel Rodrigues da
    The study aimed at formulating lessons from the Brazil's Programme for the Socio-Environmental Development of Rural Family Production (PROAMBIENTE) in the Transamazon Highway pole in the Xingu region, Para State. The methodology included interviews to small farmers as well as institutional actors that participated in the Programme. From the analysis of the Programme interventions some important lessons could be formulated, among them the need to: i) involve farmers with a real interest an capacity to assume risks; ü) avoid paternalistic behaviors (based on donations); üi) ensure continuity of key activities such as the scheme for payment for environmental services; iv) use an integrated approach of the production system; v) shift the way technical assistance and rural extension are conceived and practiced; vi) strengthen the local rural organization; vü) generate value-add to production thru processing and commercialization of products of economic importance; and vüi) avoid the creation of false expectations among farmers.
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    Retenção do dimetoato e sua relação com pH e teores de argila e matéria orgânica nos sedimentos da zona não-saturada de uma microbacia no nordeste paraense
    (Instituto Nacional de Pesquisas da Amazônia, 2007-06) LIMA, Lilianne Maia; SOUZA, Eliene Lopes de; FIGUEIREDO, Ricardo de Oliveira
    On smallholder farms of eastern Amazonia, in particular the northeast of the Pará state, heavy by pesticide applications at industrial half-perennial crops are very common. Due to their large use, mainly the dimethoate, in the catchment of the Cumaru stream, Igarapé-Açu county, we evaluated the retention process of this compound in samples of the non saturated zone, as well as verified the effects of soil pH and clay and organic mater contents in this process. Among the main pesticides the farmers use in this region, dimethoate was selected for this study, due to its larger leaching potential according to the GUS (Groundwater Ubiquity Score) index. A sorption experiment was carried out to evaluate the retention of the dimethoate in sediments in the non saturated zone. The experiment showed that the sorption of the dimethoate varied from 2.5% to 36.2% (initial concentration of 20 mg.l-1) and from 6.2% to 31.0% (initial concentration of 10 mg.l-1). These data demonstrate a high contamination potential of the groundwater by this compound, mainly due to its high mobility and low retention capacity. The dimethoate sorption rates were positively related to organic matter content in the sediments. On the other hand, values have an inverse relationship with the sorption rates of dimethoate, while clay content did not produce any effect on its retention.
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