113 research outputs found
Comparative environmental analysis of soil sampling methods in precision agriculture for lime application in ParanĂĄ State, Brazil
Precision agriculture (PA) provides techniques that favour the localized application of
inputs allowing their rational use. This makes the PA a potential indicator of reduced operational
costs, input volume, and environmental impacts. The objective of this study was to evaluate and
compare the environmental effects of three different sampling methods used in PA for the lime
application. The first sampling method evaluated was the grid sampling (GS). It was performed
at a density of one sample per hectare in a 100Ă100 m georeferenced grid. The second method
was the directed sampling, that was performed after defining the management zones by soil
apparent electrical conductivity (ECa) using a soil electrical conductivity sensor. The lest
sampling method was the Altitude-based management zone (AMZ) sampling that was developed
based on altitude maps of the field. These sampling methods were tested in three different areas
in the south of Brazil. This study evaluated the spatial variability of the lime volume in the soil
and compared quantitatively and spatially the recommended application volumes achieved by
each sampling method. Results highlighted that the sensor-directed soil sampling method was the
alternative that would generate the lowest environmental impact
Impacto da adubação orgĂąnica sobre a incidĂȘncia de tripes em cebola.
Analisou-se a relação entre adubação orgĂąnica e a incidĂȘncia de Thrips tabaci Lind. em cebola (Allium cepa L), na EE de Ituporanga,entre agosto e dezembro de 1998. Os tratamentos foram determinados de acordo com a necessidade de N para a cultura pela anĂĄlise de solo. Empregou-se como fonte orgĂąnica diversos adubos fornecendo 75 Kg/ha de N (esterco suĂno; adubo Barriga Verde proveniente de esterco de aves; composto orgĂąnico; esterco de peru; hĂșmus); 37,5 Kg/ha de N (metade da dose normal com esterco de suĂno); as testemunhas foram adubação mineral fornecendo 30-120-60 kg/ha de N-P2O5-K2O e o dobro da dose (60-240-120 kg/ha de N-P2O5-K2O); e testemunha sem adubação. Nenhum tratamento apresentou incidĂȘncia de T. tabaci superior Ă testemunha sem adubo. A adubação mineral em relação Ă orgĂąnica nĂŁo favoreceu significativamente a incidĂȘncia de T. tabaci . O processo de conversĂŁo do manejo do solo da ĂĄrea experimental de convencional para orgĂąnico pode ter
favorecido a infestação similar do inseto entre tratamentos. No perĂodo de maior incidĂȘncia de T. tabaci, a relação com nutrientes foi descrita por um modelo envolvendo K/Zn, B e N de maneira positiva. A correlação entre nutrientes e T. tabaci nĂŁo foi linear na maioria
das avaliaçÔes. A adubação orgĂąnica pode substituir a adubação mineral na cultura da cebola, pois foi possĂvel atingir nĂveis de produtividade similares para ambos tratamentos
Relação entre a variabilidade espacial das fraçÔes granulométricas do solo e a produtividade do feijoeiro sob plantio direto
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
The exposure of the hybrid detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays.
It consists of a surface array to measure secondary particles at ground level
and a fluorescence detector to measure the development of air showers in the
atmosphere above the array. The "hybrid" detection mode combines the
information from the two subsystems. We describe the determination of the
hybrid exposure for events observed by the fluorescence telescopes in
coincidence with at least one water-Cherenkov detector of the surface array. A
detailed knowledge of the time dependence of the detection operations is
crucial for an accurate evaluation of the exposure. We discuss the relevance of
monitoring data collected during operations, such as the status of the
fluorescence detector, background light and atmospheric conditions, that are
used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic
Avaliação energĂ©tica da produção de etanol utilizando como matĂ©ria-prima a cana-de-açĂșcar
Variabilidade qualitativa de åguas pluviais coletadas em telhado e sua importùncia na concepção do sistema de tratamento
Sobre a hipótese de estabilização das taxas de cesårea do Estado de São Paulo, Brasil
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