PHYSICAL QUALITY OF AN OXISOL UNDER NO-TILLAGE AND CONVENTIONAL TILLAGE

The understanding and quantification of the impact of tillage systems in their physical quality are fundamental in the development of sustainable agricultural systems. This study aimed to evaluate the quality of an Oxisol under conventional tillage (CT) and no-tillage system (NT), through different physical indicators. The management systems were: CT and NT for seven or eight consecutive years (medium textured soil) and CT and NT by nine and ten consecutive years (clay soil). Were determined, at the layers 0-0.10, 0.10-0.20; 0.20-0.30 m, soil resistance to penetration, total soil porosity, macroporosity and microporosity, soil water retention, S index, soil bulk density, maximum density and relative bulk density. Was observed great variation of soil resistance to penetration throughout the soybean and corn cycles, with its highest values were found in the surface layers. The NT showed greater resistance to penetration. Among the management systems, the results against indicators of soil physical quality were similar.

Spatial variability of soil CO2 emission in a sugarcane area characterized by secondary information

Soil CO2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.

Microbial alterations of the soil influenced by induced compaction

A compactação é um dos fatores mais agravantes para a qualidade do solo, porém o seu efeito na comunidade e atividade enzimática microbiana não tem sido suficientemente estudado. Seis níveis de compactação foram obtidos pela passagem de tratores com diferentes pesos em um Latossolo Vermelho, e a densidade final foi medida. Amostras de solo foram coletadas nas profundidades de 0-10 e 10-20 cm, após a colheita do milho. O efeito da compactação foi evidente em todos os parâmetros estudados, mas nem sempre foi significativo. A contagem das bactérias totais reduziu significativamente em 22-30 %, e a das nitrificantes, em 38-41 %, no solo com maior densidade em relação ao controle. Contudo, a população de fungos aumentou de 55 a 86 %, e a das bactérias desnitrificantes, de 49 a 53 %. A atividade da desidrogenase diminuiu de 20 a 34 %; a da urease, de 44 a 46 %; e a da fosfatase, de 26 a 28 %. O conteúdo de matéria orgânica e o pH do solo diminuíram na camada 0-0,10 em relação à de 0,10-0,20 m e influíram possivelmente na redução das contagens microbianas exceto das bactérias desnitrificantes, e na atividade das enzimas, menos a da urease. Esses resultados indicam que a compactação do solo teve influência na comunidade de microrganismos aeróbios e na sua atividade. Esse efeito pode alterar a ciclagem de nutrientes e diminuir a produção da planta.

Strategy of specification of management areas: rice grain yield as related to soil fertility

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Associations between healthy eating patterns and indicators of metabolic risk in postmenopausal women

Background: Since human diets contain many components that may work synergistically to prevent or promote disease, assessing diet quality may be informative. The purpose of this study was to investigate the association between quality diet, by using Healthy Eating Index (HEI), and metabolic risk indicators in postmenopausal women.Methods: This cross-sectional study included a total of 173 Brazilian women, aged 45-75 years, seeking healthcare at a public outpatient center. Food consumption assessed by 24 h-recall food inquiry was used to calculate HEI scores: >80 implied diet good, 80-51 diet needed improvement, and <51 diet poor. Anthropometric data included: body mass index (BMI = weight/height(2)), waist-circumference (WC), body fat (%BF) and lean mass (%LM). Data on total cholesterol (TC), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), and triglycerides (TG) were also collected. Fisher's Exact test, and logistic regression method (to determine odds ratio, OR) were used in the statistical analysis.Results: Overweight and obesity were observed in 75.7% of the participants. Excessive %BF (> 35%) was observed in 56.1%, while %LM was reduced (<70%) in 78.1%. WC was elevated (= 88 cm) in 72.3%. Based on HEI values, diet quality was good in 3% (5/173), needed improvement in 48.5% (84/173), and was poor in 48.5% (84/173) of the cases. In this group, 75% of women had high intakes of lipids (> 35%), predominantly saturated and monounsaturated fat. on average, plasma TC, LDLC, and TG levels were higher than recommended in 57.2%, 79.2% and 45.1% of the women, respectively, while HDLC was low in 50.8%. There was association between HEI scores and the %BF that it was higher among women with HEI score < 80 (p = 0.021). There were not observed significant risk associations between HEI and lipid profile.Conclusion: Among the Brazilian postmenopausal women attending a public outpatient clinic, diet was considered to need improvement or to be of poor quality, attributed to high saturated fat ingestion, which probably caused a negative impact on metabolic risk indicators, namely body composition.

Histological and Histochemical Analysis of the Fat Body of Rhinocricus padbergi (Diplopoda) Exposed to Contaminated Industrial Soil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Performance of a reciprocal shaker in mechanical dispersion of soil samples for particle-size analysis

A dispersão da amostra de solo é uma etapa fundamental da análise granulométrica, sendo realizada mediante o uso de dispersantes químicos e agitação mecânica. O objetivo deste trabalho foi avaliar a eficiência de mesa agitadora reciprocante de baixa rotação na dispersão mecânica de amostras de solos de diferentes classes texturais. Foram realizadas análises granulométricas em 61 amostras com quatro repetições, empregando o método da pipeta para determinação da fração argila e tamisagem para determinação das frações areia grossa, areia fina e areia total, sendo o silte determinado por diferença. Na avaliação de desempenho, os resultados obtidos com uso da mesa agitadora reciprocante (MAR) foram comparados com dados disponíveis para as mesmas amostras oriundos de relatórios do Ensaio de Proficiência IAC para Laboratórios de Análises de Solos - Prolab/IAC. Análises de acurácia foram realizadas com base nos valores dos intervalos de confiança definidos para cada fração granulométrica componente de cada amostra ensaiada. Indicadores gráficos também foram utilizados na comparação de dados, por meio de dispersão e ajuste linear. A estatística descritiva indicou preponderância de baixa variabilidade em mais de 90 % dos resultados obtidos para as amostras de texturas arenosa, média e argilosa e em 68 % dos obtidos para as amostras de textura muito argilosa, indicando boa repetibilidade dos resultados obtidos com a MAR. Média variabilidade foi mais frequentemente associada à fração silte, seguida da fração areia fina. Os resultados das análises de sensibilidade indicam acurácia de 100 % nas três frações granulométricas - areia total, silte e argila - para todas as amostras analisadas pertencentes às classes texturais muito argilosa, argilosa e média. Para as nove amostras de textura arenosa, a acurácia média foi de 85,2 %, e os maiores desvios ocorreram em relação à fração silte. Nas aproximações lineares, coeficientes de correlação igual (silte) ou superiores (areia total e argila) a 0,93, bem como diferenças menores do que 0,16 entre os coeficientes angulares das retas e o valor unitário, indicam alta correlação entre os resultados de referência (Prolab/IAC) e os obtidos nos ensaios com a MAR. Conclui-se pelo desempenho satisfatório da mesa agitadora reciprocante de baixa rotação para dispersão mecânica de amostras de solo de diferentes classes texturais para fins de análise granulométrica, permitindo recomendar o uso alternativo do equipamento quando se emprega agitação lenta. As vantagens do uso do equipamento nacional incluem o baixo custo, a possibilidade de análise simultânea de grande número de amostras e o uso de frascos comuns, de vidro ou de plástico, baratos e de fácil reposição.

Prediction of soil shear strength in agricultural and natural environments of the Brazilian Cerrado

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Resistência do solo à penetração e ao cisalhamento em diversos usos do solo em áreas de preservação permanente

The soil resistance to penetration and shear can be used as indicators of soil compaction and to indicate the susceptibility of a soil to erosion. The objective of this study was to quantify and compare the impact provided by different land uses in a haplic cambissol in areas of permanent preservation, from the soil resistance to penetration and shear. The experimental area was located in an area of permanent preservation, the sub-basin of the Ribeira Iguape River - SP, with different land uses: banana cultivation - CBAN, degraded pasture - PDEG, silvopastoral system - MPIS and native forest - MNAT. The test for resistance to penetration was accomplished with a digital penetrometer compaction of manual effort, to a depth of 40 cm. The soil shear strength was determined by Vane Test at a depth between 0 and 5 cm. The degraded pasture was similar to native forest, with less resistance to penetration. The banana cultivation and silvopastoral system were the land uses with the highest resistance to penetration, bringing serious risk of erosion in areas of permanent preservation. The soil under native forest had lower shear strength. The cultivation of bananas, degraded pasture and silvopastoral system were the land uses with higher shear strength of soil, indicating that the use of these soils in areas of permanent preservation is promoting the same compression.

Reduction capability of soil humic substances from the Rio Negro basin, Brazil, towards Hg(II) studied by a multimethod approach and principal component analysis (PCA)

This paper characterizes humic substances (HS) extracted from soil samples collected in the Rio Negro basin in the state of Amazonas, Brazil, particularly investigating their reduction capabilities towards Hg(II) in order to elucidate potential mercury cycling/volatilization in this environment. For this reason, a multimethod approach was used, consisting of both instrumental methods (elemental analysis, EPR, solid-state NMR, FIA combined with cold-vapor AAS of Hg(0)) and statistical methods such as principal component analysis (PCA) and a central composite factorial planning method. The HS under study were divided into groups, complexing and reducing ones, owing to different distribution of their functionalities. The main functionalities (cor)related with reduction of Hg(II) were phenolic, carboxylic and amide groups, while the groups related with complexation of Hg(II) were ethers, hydroxyls, aldehydes and ketones. The HS extracted from floodable regions of the Rio Negro basin presented a greater capacity to retain (to complex, to adsorb physically and/or chemically) Hg(II), while nonfloodable regions showed a greater capacity to reduce Hg(II), indicating that HS extracted from different types of regions contribute in different ways to the biogeochemical mercury cycle in the basin of the mid-Rio Negro, AM, Brazil. (c) 2007 Published by Elsevier B.V.

Biological indicators of stress in pacu (Piaractus mesopotamicus) after capture

Os efeitos da captura (perseguição, contenção em puçá e exposição aérea) no perfil sanguíneo do cortisol, glicose, cloreto, sódio, potássio, cálcio e na osmolaridade, hematócrito, hemoglobina, número de células vermelhas (CV) e volume corpuscular médio (VCM) foram investigados no pacu (Piaractus mesopotamicus). Um total de 132 peixes (49,7 ± 11,7 g) foi submetido à captura com 3 ou 5 minutos de exposição aérea. Nove peixes de cada tratamento foram amostrados 5, 15, 30, 60 minutos e 24 horas depois e outros nove peixes foram amostrados antes da captura e considerados controle. A captura resultou em aumento do cortisol e glicose no sangue 30 e 5 minutos depois da captura, respectivamente, independente do tempo de exposição aérea. Ambos os indicadores recuperaram os valores controle em 24 horas. Nos dois grupos de peixes, o cloreto plasmático diminuiu 60 minutos após captura e não recuperou os valores controle, enquanto o sódio sérico aumentou entre 15 e 30 minutos recuperando a condição controle em 24 horas. Não houve alteração significativa nos valores de potássio, cálcio, osmolaridade ou no hematócrito, hemoglobina, CV e VCM como consequência da captura. Os estressores sequenciais aplicados no pacu durante a captura ativaram o eixo cérebro-pituitária-interrenal (respostas do cortisol e glicose), mas a ativação do eixo cérebro-sistema simpático-células cromafins foi aparentemente moderada (respostas iônicas e hematológicas).

Performance and economic indicators of a large scale fish farming in Mato Grosso, Brazil

Performance and economic indicators of a large scale fish farm that produces round fish, located in Mato Grosso State, Brazil, were evaluated. The 130.8 ha-water surface area was distributed in 30 ponds. Average total production costs and the following economic indicators were calculated: gross income (GI), gross margin (GM), gross margin index (GMI), profitability index (PI) and profit (P) for the farm as a whole and for ten ponds individually. Production performance indicators were also obtained, such as: production cycle (PC), apparent feed conversion (FC), average biomass storage (ABS), survival index (SI) and final average weight (FAW). The average costs to produce an average 2.971 kg.ha-1 per year were: R$ 2.43, R$ 0.72 and R$ 3.15 as average variable, fixed and total costs, respectively. Gross margin and profit per year per hectare of water surface were R$ 2,316.91 and R$ 180.98, respectively. The individual evaluation of the ponds showed that the best pond performance was obtained for PI 38%, FC 1.7, ABS 0.980 kg.m-2, TS 56%, FAW 1.873 kg with PC of 12.3 months. The worst PI was obtained for the pond that displayed losses of 138%, FC 2.6, ABS 0.110 kg.m-2, SI 16% and FAW 1.811 kg. However, large scale production of round-fish in farms is economically feasible. The studied farm displays favorable conditions to improve performance and economic indicators, but it is necessary to reproduce the breeding techniques and performance indicators achieved in few ponds to the entire farm.

Development of a quality index method (QIM) sensory scheme and study of shelf-life of ice-stored blackspot seabream (Pagellus bogaraveo)

The aim of this work was to develop a quality index method (QIM) scheme for whole ice-boxed refrigerated blackspot seabream and to perform shelf-life evaluations, using sensory analysis, GR Torrymeter measurements and bacterial counts of specific spoilage organisms (SSO) during chilled storage. A QIM scheme based on a total of 30 demerit points was developed. Sensory, physical and microbiological data were integrated and used to determine the rejection point. Results indicated that the shelf-life of blackspot seabream is around 12-13 days. (C) 2011 Elsevier Ltd. All rights reserved.

Fractal dimension and anisotropy of soil CO2 emission in a mechanically harvested sugarcane production area

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)