Agricultural impacts of hydrobiogeochemical cycling in the Amazon: is there any solution?

Abstract: Expansion of agriculture in the Brazilian Amazon has been driven not just by demands from traditional, rural producers, but also large agriculture and cattle producers, both of whom have put considerable pressure on remaining forests and their watersheds. Monitoring of these watersheds has been a focus of intensive study for the past 20 years and although this work has greatly increased our understanding, considerable gaps still remain in our ability to provide adequate recommendations for land management and associated public policies. In this study we present a summary of findings from these previous results. For small properties, the use of fire to prepare land for cultivation remains controversial, while in large properties, forest conversion to pasture and/or crop production has had a meaningful and adverse effect on water quality. Riparian forest conservation can make a significant difference in reducing impacts of land-use change. Secondary vegetation can also play an important role in mitigating these impacts. New types of sustainable agricultural production systems, together with incentives such as payments for ecosystem service can also contribute. Continued monitoring of these changes, together with robust sustainable development plans, can help to preserve forest while still addressing the social and economic needs of Amazonian riverine inhabitants

CO2-driven cation leaching after tropical forest clearing.

The objective of this study was to investigate the role of dissolved CO2 (H2CO3*) as a mechanism of cation removal from surface soils under secondary land uses in the tropics. Soil leachate columns were prepared with 0?10 cm soils from mature and secondary forest, and managed pastures, and extracted with H2CO3* from deionized water equilibrated with 0%, 0.5%, 1%, and 10% CO2 (g). Extraction of soil cations slowed over time following an exponential form for the cumulative data. The rate of cation concentration decline varied as a function of CO2 concentration with the 10% solution resulting in a greater percent decline with extraction volume. Potassium removal from the exchange sites of all soils and for all solutions was nearly complete ranging from 85% to 97% while removals of Mg (31% to 71%) and Ca (12% to 42%) were lower. The asymptotic patterns of cation loss observed in this study suggest that H2CO3* acid-driven losses of cations may become self-limiting over time. Other stronger acids from atmospheric deposition or organic sources may serve to perpetuate cation removal, and re-forestation on these cleared lands would certainly re-distribute cations from soils to vegetation

Tree growth soil response to P fertilization in a 24-year-old tropical forest on an Oxisol.

Abstract ID: 82

Dissolved CO2 in small catchment streams of Eastern Amazonia.

Poster 525. Disponível também on-line

Utilização de imagens Landsat e CBERS na avaliação da mudança do uso e cobertura da terra e seus reflexos na qualidade da água em microbacia hidrográfica do município de Paragominas, Pará.

As examples of human activities that may provoke changes in the stability and in the dynamic equilibrium of the river basin system, we have deforestation, burned areas, predatory agriculture, urbanization and other ways of soil occupation without any environmental planning. The combination of remote sensing (TM Landsat and CBERS images ) and geoprocessing products and techniques are valuable tools to subsidize studies of the land use. The results in this first stage of the project indicate a relation between the increasing of the conductivity in the water of microbasin with the increasing of the plantation areas of grains and the decreasing of the primary and secondary forest areas (Capoeiras). The results show that the changes in the use of the land are provoking an increase in the concentration of the nutrients and a consequent diminution of the water quality of the Igarapé Cinqüenta e Quatr

Low-Dose Naltrexone for Pruritus in Systemic Sclerosis

Pruritus is a common symptom in systemic sclerosis (SSc), an autoimmune disease which causes fibrosis and vasculopathy in skin, lung, and gastrointestinal tract (GIT). Unfortunately, pruritus has limited treatment options in this disease. Pilot trials of low-dose naltrexone hydrochloride (LDN) for pruritus, pain, and quality of life (QOL) in other GIT diseases have been successful. In this case series we report three patients that had significant improvement in pruritus and total GIT symptoms as measured by the 10-point faces scale and the University of California Los Angeles Scleroderma Clinical Trials Consortium Gastrointestinal Tract 2.0 (UCLA SCTC GIT 2.0) questionnaire. This small case series suggests LDN may be an effective, highly tolerable, and inexpensive treatment for pruritus and GIT symptoms in SSc

Monitoring Astronauts’ Status through Non-Invasive Positive Pressure Ventilation

Many hospitalized patients with respiratory failure are treated with non-invasive positive pressure ventilation (NiPPV). In many cases non-invasive ventilation can be used to successfully treat patients and subsequently avoid endotracheal intubation. Recent literature and clinical practice have shown that in patients who are protecting their airway, and in whom the pH is not dangerously low, the use of non-invasive positive pressure ventilation can be effective (1). Additional studies argue that NiPPV in more severely ill patients (pH \u3c 7.2) with chronic obstructive pulmonary disease (COPD) is no worse than endotracheal intubation (2,3) with regard to mortality, lengths of stay and readmission rates. Furthermore, better outcome was confirmed for patients who succeeded NiPPV and avoided endotracheal intubation. Thus, the non-invasive mode of ventilation can assist patients in ventilating equally or more effectively, and in many cases can be used to avoid the more invasive endotracheal intubation. Many studies have evaluated treatment failures of NiPPV. Failure rates range from 30-80% depending on the cause of respiratory failure and underlying medical condition(s) of patient population (4). Other studies have looked at factors which predict NiPPV failure, such as physiologic scoring (age, severity of underlying illness) and presence of acute respiratory distress syndrome (ARDS) or community acquired pneumonia (CAP) (5). Having an objective and real time means of early identification of patients that will fail NiPPV would greatly benefit patients by helping physicians intervene early with endotracheal intubation when indicated

Hidrogeoquímica de um córrego amazônico: o caso de um igarapé na flona do Tapajós, Pará, Brasil.

Resumo: Decorrente do seu imenso tamanho e das dificuldades de acesso a áreas remotas é desafiadora a geração de informação sobre a hidrogeoquímica de microbacias na Bacia Amazônica. Um estudo, ao longo de quatro anos, em um igarapé na Flona do Tapajós, apresentou resultados que contribuem para a ampliação do conhecimento sobre os processos hidrogeoquímicos atuantes na região. Estes revelam condições fluviais de baixa carga iônica, característica de solos bastante intemperizados, e uma situação prístina com abundante ciclagem de nitrogênio na microbacia, refletidas em concentrações de amônio e nitrato que superam as de constituintes maiores da hidrogeoquímica fluvial. Abstract: Due to its huge size and the difficulties of accessing remote forest areas it is a challenge to generate data about the hydrogeochemistry of small catchments in the Amazon Basin. A four year study of a stream in the Flona do Tapajós has shown results that contribute to increase the knowledge about the hydrogeochemical processes in the region. These findings reveal stream conditions of low ionic charge, a characteristic of high weathered soils, and a pristine situation with an abundant nitrogen cycling in the catchment, resulting in ammonium and nitrate concentrations that overlap those of the mayor elements of the fluvial hydrogeochemistry. Abstract: Due to its huge size and the diffi culties of accessing remote forest areas it is a challenge to generate data about the hydrogeochemistry of small catchments in the Amazon Basin. A four year study of a stream in the Flona do Tapajós has shown results that contribute to increase the knowledge about the hydrogeochemical processes in the region. These fi ndings reveal stream conditions of low ionic charge, a characteristic of high weathered soils, and a pristine situation with an abundant nitrogen cycling in the catchment, resulting in ammonium and nitrate concentrations that overlap those of the mayor elements of the fl uvial hydrogeochemistry

Crescimento de cinco espécies nativas em successão natural na Amazônia Oriental.

Na Amazônia Legal brasileira, mandioca (Manihot esculenta) é uma colheita principal para populações rurais cuja produção é feita através de agricultura iniciada com queimada. Sistemas agroflorestais de corte e trituração estão sendo implementados na Amazônia Legal para substituir o fogo em sistemas de produção. Em abril de 2005, um hectare de floresta secundária de sete anos de idade foi derrubado usando um tractor TRITUCAP do Projeto Tipitamba para preparar o terreno para o projeto no campus de pesquisa de UFRA em Igarapé Açu, Pará, Brasil. Um sistema agroflorestal foi implementado em todas as parcelas usando espécies de árvores nativas em plantio misto com M. esculenta. A pesquisa foi analisada utilizando um fatorial duplo com duas parcelas-principais (com ou sem adubo P e K) e dois tratamentos parcelas-secundárias (com ou sem a espécie fixadora de N2, Inga edulis). As árvores, mandioca, competição, capa orgânica e solo foram medidos após 1 e 2 anos. Depois de vinte meses de cultura mista, M. esculenta foi colhida e a parcela se deixou à sucessão natural. Depois de 4 anos de crescimento de vegetação secundaria, ou 6 anos após plantio, as árvores plantadas foram medidas em altura, DAP e DAB. Adubação com P e K diminuiu a sobrevivência de todas as espécies, menos P. multijuga, mas a presença de I. edulis não teve efeito. Adubação com P e K aumentou o crescimento de todas as espécies depois de 6 anos mas a presença de I. edulis nao apresentou efeito significativo no crescimento das árvores.Editores técnicos: Roberto Porro, Milton Kanashiro, Maria do Socorro Gonçalves Ferreira, Leila Sobral Sampaio e Gladys Ferreira de Sousa