Perda de nutrientes por escoamento superficial em microbacias do Nordeste paraense sob uso agrícola.

Uma das etapas do ciclo hidrológico refere-se à água da chuva que precipita sobre um ecossistema terrestre entra em contato com a superfície vegetal ou cai diretamente sobre a superfície do solo. Já no solo, a água pode evaporar ou compor a solução do solo, disponibilizando os nutrientes para os vegetais e microrganismos. Por sua vez, a água que escoa na superfície do terreno em direção aos cursos d?água, processo denominado escoamento superficial, carreia os nutrientes presentes no solo para os recursos hídricos, o que é de fundamental importância para a biota aquáticae para a qualidade da água. Portanto, as propriedades do solo influenciam na transferência desses nutrientes para o ecossistema aquático. Assim, alterações sobre o ecossistema provocadas pelo homem podem alterar parte do ciclo hidrológico quanto à quantidade e qualidade da água. Nesse contexto, apresenta-se a etapa prévia do projeto em questão, a qual foi reconhecer e definir as microbacias onde será realizada a pesquisa, realizar treinamento de campo e laboratório, e iniciar levantamento bibliográfico

Transferência de nutrientes por vias hidrológicas em três pequenas bacias sob uso agrícola familiar no nordeste paraense: chuva, escoamento superficial em solos e águas fluviais.

Poster 651. Disponível também on-line

GRASS UTILIZATION IN GROWING FINISHING BÍSARO PIGS (85-107 KG). PERFORMANCE AND CARCASS COMPOSITION

The use of different quantities of vegetables, forages or fresh grass as fodder for growing-finishing pigs is an important factor of the northern Portugal traditional system. The increasing development of swine production in outdoor systems, extensive and organic production, turns to upcoming natural diets, in which grass performs a significant part. With regard to this, some investigation has been made concerning the use of fibre-rich feed ingredients in pig nutrition. Metabolic effects of its ingestion are analysed concerning different sights (economical, social, environmental and physiological ones). The aim of this work was to study the effects of grass utilization in the diets on performances of finishing Bísaro pigs. A total of 22 pigs (16 castrated males and 6 females) was housed outdoor and fed ad libitum (37 – 85 kg live weight) with a growing diet and then transferred to an indoor system (with free access to an outdoor area) for 49 days, according to 3 different treatments: 100% concentrate (C), 75% concentrate + ad libitum grass (CE75), 50% concentrate + ad libitum grass (CE50). The grass was supplied and its intake registered on a daily basis. Every 14 days, the pigs were weighted and their back fat (P2 in vivo) measured. After slaughter (average weight of 107 kg LW), yield and ½ left carcass characteristics were controlled. During the outdoor growing phase, the ADG was 513 g/day. During the indoor finishing phase, the increase grass intake was proportional to the reduction of concentrate in the diet. The ADG (g) and the fat deposition (P2 cm) were significantly different (P<0,05) in the 3 treatments (ADG: C=641, CE75=467, CE50=356 and: C=11,4, CE75=+9,5, CE50=+6,2). The empty body weight (kg) was also proportional to the intake of concentrate (C=116,2; CE75=107,7; CE50=102,2). Comparatively to the weight of the body parts, pigs that had higher intake of grass and lower of concentrate showed a higher % of shoulder (P<0,05; C=20,4, CE75=21,7, CE50=22,2) and the pH45min of CE carcasses was significantly higher (P<0,05). As a conclusion, concentrate substitution for grass showed a slower growing rate, thinner carcasses and a high technological quality. Neverthelles variability (CV %) of the productive parameters at the end of this study were higher in the treatments that included grass: live weight (C= 10,5%; C75=10,7%; C50=14,3%), finishing ADG (C=24%; C75=37%, C50=42%), and final fat (C=37%; C75=32%, C50=52%). These values suggest that the utilization of fibrous feeds in growing-finishing swine may be one of the possible explanations of the more heterogeneous products and carcasses found in the traditional or extensive systems, common users of fibrous feeds in the carcass finishing phase

Water quality-quantity evaluation of the Ribeirão das Posses Watershed, Brazil, applying the AgES-W model.

Southeastern Brazil is under a period of drought that has impacted the conservation of watersheds and the management of water quality and quantity for agricultural and urban demands. In this context agro-hydrological modeling tools can generate information of water response over time in response to climate and landuse changes. A 12-km2 watershed which has suffered from anthropogenic activities is the Ribeirão das Posses watershed that is located in the extreme south of Minas Gerais State and is a headwater catchment of the Jaguari river, one of the contributing rivers of the Cantareira Reservoir Complex in the state of São Paulo. This watershed had its landscape changed over the last century from native forests to more homogeneous vegetation for pastures and small crops and some forest plantations fragments with eucalyptus. Currently, the Conservative Waters project has planted some small areas with vegetation of native species, especially where there are springs and at the top of the hills, in order to recover degraded areas and improve the hydrogeochemistry in this study basin. In this context, the AgroEcoSystem-Watershed (AgES-W) model is presented to simulate the water movement and storage in agricultural watersheds with different spatial resolutions of land areas or hydrological responses units. The objectives are to evaluate the quality and quantity of water in Ribeirão das Posses Basin using measured data, then simulate these responses in space and time to test the AgES-W model. The period chosen for research was from 2011 to 2015, because the water quality data were collected during this period. The answers that we hope to find out are: How well does the AgES-W model simulate this Brazilian watershed in the tropics? What are the future prospects of the quality and quantity of water in this basin? The results will help to guide hydrological simulations in similar tropical environments in Brazil in this and other agricultural watersheds with AgES-W

Influência do uso da terra no Nordeste Paraense sobre indicadores físico-químicos de qualidade da água do escoamento superficial no solo.

RESUMO: O presente trabalho teve como objetivo caracterizar a hidrogeoquímica do escoamento superficial em solos de diferentes ecossistemas, na mesobacia dos igarapés contíguos Timboteua e Buiuna (afluentes do rio Marapanim) no nordeste paraense, monitorando-se duas variáveis físicoquímicas da água (condutividade elétrica e pH). Foram alocadas três parcelas experimentais (1m2) em seis ecossistemas, sob mesmas condições biofísicas de solo e clima, totalizando 18 parcelas de tratamento. Instalaram-se também na mesma bacia três coletores de água de chuva e dois pluviômetros. No período de janeiro a junho de 2010, foram coletadas 234 amostras água de chuva e de escoamento superficial. O pH apresentou-se mais ácido nas amostras de água da chuva, seguido pela Capoeira e Sistema Agroflorestal (com preparo por derruba-e-queima), que pode estar relacionado à concentração de material orgânico em decomposição. Os agroecossistemas Roça (derruba-e-queima), Sistema Agroflorestal (com preparo por corte-e-trituração) e Pastagem se destacaram apresentando os maiores valores de condutividade elétrica (CE). O manejo do solo parece influenciar a CE e o pH. Abstract: The objective of this study was to characterize the hydrogeochemistry of the overland flow, in the watershed of the Timboteua and Buiuna streams (tributaries of the Marapanim River), Northeast of Pará, through measurements of two physico-chemical variables of water (electrical conductivity and pH). It was placed three experimental plots (1m2) in each six ecosystems, under the same biophysical conditions of soil and climate, summing up 18 treatment plots. It was also installed three rainwater collectors and two rain gauges in the same watershed. In the period January to June/ 2010, it was collected 234 rainwater and overland flow samples. The pH was more acidic in rainwater samples, followed by Capoeira and agroforestry system (prepared by slash-and-burn) overland flow samples, what may be related to the soil organic matter decomposition. Agroecosystems (slash-and-burn), Agroforestry system (chop-and-mulch) and Pasture overland flow were distinguished by higher electrical conductivity (EC). Soil management seems to influence both EC and pH

Caracterização hidroquímica do escoamento superficial em diferentes agroecossistemas no Nordeste Paraense.

PIBIC 2010

Caracterização e análise da rentabilidade financeira do cultivo da teca (Tectona grandis L.f.) para produção de madeira em Rio Branco, Acre.

A teca (Tectona grandis L.f.), planta originária da Ásia, encontra-se em expansão nas regiões Centro-Oeste e Norte do Brasil. O principal produto dessa espécie é a madeira de alta qualidade, muito utilizada em móveis finos e na construção naval. O valor de mercado para a madeira de teca madura, livre de nós e com diâmetro para serraria, chega a superar o da espécie mogno (Swietenia macrophylla King). Apesar da potencialidade de mercado para a teca, no Brasil ainda são escassos os trabalhos que avaliam o potencial econômico dessa espécie considerando as várias formas de manejo. Assim, estudos dessa natureza contribuirão para o planejamento e administração dos atuais e futuros plantios de teca. Tendo como referência estudos sobre os povoamentos de teca nos estados do Acre e Rondônia, este trabalho tem como objetivo determinar, em diferentes estratégias de manejo, o valor presente líquido (VPL), a relação benefício-custo (RBC), a taxa interna de retorno (TIR) e analisar a sensibilidade dos indicadores econômicos quanto à oscilação na taxa mínima de atratividade (TMA) e nos preços da madeira.bitstream/item/28922/1/Circular-tec.-53.pd

Dissolved CO2 in small catchment streams of Eastern Amazonia.

Poster 525. Disponível também on-line

A Contribution to 3D Digital Lines

We propose in this paper a new approach to three-dimensional digital lines (3DDLs) based on the study of the integer lattice generated by the projection of Z3 onto an euclidean plane which reduces the problem to dimension 2. The many properties of this lattice lead to an arithmetical definition of 3DDLs in accordance with a topological characterization. This definition is then used in an algorithm that calculates the intersection between a naive 3DDL and an arbitrary digital plane. We also show that this algorithm can be extended to calculate the intersection between a plane and a set of adjacent 3DDLs incrementally in a very efficient manner