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

Student-Student Interaction In An Online Continuing Professional Development Course: Testing Anderson's Equivalency Theorem

Supervisor: Dr. Martha Cleveland-InnesContinuing education programs for laboratory professionals benefit from the creation of a community of inquiry which encourages students to think critically and learn deeply. Student-student interactions are an essential factor in that structure. This research asked the question, “Is interaction between students a necessary component of online learning for medical laboratory professionals?” The study examined the impact of student-student interactions in an online professional development course in medical laboratory science. Anderson’s equivalency theorem serves as a theoretical frame and identifies categories of the independent variable, student-student interaction. Three dependant variables were explored: (1) student test scores; (2) quantities of student-content and student-instructor interactions; and (3) change in student approaches to learning. Results show statistical significance for student-content and student-instructor interactions. Findings approached the level of significance for surface approach scores. Simple measures of effect showed the relationship of a mildly positive change in deep approach scores combined with a moderately negative change in surface approach scores for the treatment group. Although the study was hampered by a short experimental time-frame and a small sample size, evidence supports the inclusion of student-student interactions via CMC in online instruction for medical laboratory continuing education programs

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

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

Five native tree species and manioc under slash-and-mulch agroforestry in the eastern Amazon of Brazil: plant growth and soil responses.

Throughout the Amazon of Brazil, manioc (Manihot esculenta) is a staple crop produced through slash-and-burn agriculture. Nutrient losses during slash-and-burn can be large and nutrient demand by food crops so great that ?elds are often abandoned after two years. In recent decades, farmers have reduced the fallow phase from 20 to *5 years, limiting plant nutrient accumulation to sustain crop yields. Improved fallows through simultaneous planting of trees with food crops may accelerate nutrient re-accumulation. In addition, slash-and-mulch technology may prevent loss of nutrients due to burning and mulch decomposition may serve as a slow-release source of nutrients. This study in Para´, Brazil, in a 7-year-old secondary forest following slashing and mulching of the vegetation, involved two main plot treatments (with and without P and K fertilizers) and two sub-plot treatments (with or without a N2-?xer Inga edulis). A mixed-culture of trees and manioc was planted in all plots. P and K fertilizer increased tree mortality due to weed competition but growth of surviving trees in four of the ?ve tree species tested also increased as did biomass production of manioc. In the N2-?xer treatment trends of greater growth and survival of four of ?ve tree species and manioc biomass were also observed. Fertilization increased the biomass of competing vegetation, but there was a fertilizer by N2 -?xer interaction as I. edulis caused a reduction in competing biomass in the fertilized treatment. After one year, fertilization increased decomposition of the mulch such that Ca, Mg, and N contents within the mulch all decreased. In contrast, P and K contents of mulch increased in all treatments. No in?uence of the N2 -?xer on 0–10 cm soil N contents was observed. Two years after establishment, this agroforestry system succeeded in growing a manioc crop and leaving a well-maintained tree fallow after the crop harvest

Разработка программы мероприятий по внедрению наилучших доступных технологий на примере теплоэнергетики

В связи с изменениями экологического законодательства в РФ обязательным требованием будет являться переход предприятий на НДТ с 2020 года. В работе будут предложены мероприятия для уменьшения воздействия теплоэнергетических предприятий на атмосферный воздух путем перехода на НДТ.In connection with the change in environmental legislation in the Russian Federation, the mandatory requirement will be the transition to BAT since 2020. The work will propose measures to reduce the impact of heat power plants on atmospheric air by switching to BAT

Stream water chemistry assessment in agriculture catchments in Eastern Amazonia.

Poster 568. Disponível também on-line