Papers by Fabricio P Povh
Ciência e Agrotecnologia, 2017
Agricultural residual biomass is an important source of energy, and its production and quality va... more Agricultural residual biomass is an important source of energy, and its production and quality vary according to the crop management. This study aimed to assess the effects of plant distribution and nitrogen fertilization on the energy production potential of the biomass of maize cultivated under no tillage. The field experiment was installed in southeast Brazil using five nitrogen rates (0, 60, 120, 180, and 240 kg ha-1) and two inter-row spacings (0.4 and 0.8 m). Grain yield, residual biomass productivity, and bioenergy potential in different parts of the plant (grain, stalk+leaf, husk, and cob) were assessed. No change in grain yield was observed using narrow row spacing. Stalk+leaf and husk productivity was higher using 0.8 m than using 0.4 m of inter-row spacing. Nitrogen application resulted in increased grain yield and biomass productivity. Nitrogen influences the bioenergy potential by increasing the biomass and calorific value. Application of the maximum nitrogen fertilizat...
Agronomy, Sep 23, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Energy flow analysis is an interesting approach to assess and to improve sustainability of agricu... more Energy flow analysis is an interesting approach to assess and to improve sustainability of agricultural production systems, represented by the economy of energy resources and other inputs translated into energy terms. This type of analysis can complement the economic view contributing to more efficient production systems. Moreover, assessing crops with traditional food use may play an important role in energy provision. Energy efficiency tools were applied in order to determine the energy demand as well as the efficiency of the biomass production of several forage crops in mechanized systems conducted at Paraná state, Brazil. Material flow, input and output energy, energy balance, energy return over investment and embodied energy were used and identified that maize and sorghum were the crops that uses energy in the most efficient way, represented by the best results at net energy availability, profitability and embodied energy at the final product. Oat and ryegrass were the crops that presented the least efficient energy uses in the biomass production systems.
Pesquisa Agropecuária Brasileira, 2008
O objetivo deste trabalho foi avaliar, com um sensor ótico ativo, o comportamento do índice de ve... more O objetivo deste trabalho foi avaliar, com um sensor ótico ativo, o comportamento do índice de vegetação por diferença normalizada (NDVI - "normalized difference vegetation index"), nas culturas de trigo, triticale, cevada e milho. Cinco experimentos foram conduzidos no Paraná e São Paulo, com variação de classes de solo, doses e fontes de N, e variedades de trigo. As seguintes variáveis foram avaliadas: NDVI, teor de N foliar, matéria seca e produtividade das culturas. Análises de regressões foram realizadas entre as doses de N aplicadas e NDVI, teor de N foliar, matéria seca e produtividade. Análises de correlação entre as variáveis foram realizadas. O trigo, triticale e cevada apresentaram resposta às aplicações de doses crescentes de N, pelo aumento nas leituras do NDVI, no teor de N foliar e na produtividade. Medido pelo sensor ótico ativo utilizado, o NDVI apresenta alto potencial para manejo do N nas culturas do trigo, triticale e cevada, e baixo potencial para a cu...
Revista Brasileira de Engenharia de Biossistemas, 2009
Active optical sensors are a new approach for site specific nitrogen management on real time and ... more Active optical sensors are a new approach for site specific nitrogen management on real time and they have been successfully used on grain crops. This work consisted in evaluating the behavior of the Normalized Difference Vegetation Index (NDVI) using a commercial active optical sensor on 28 sugarcane varieties, as well as analyzing the temporal behavior of this index for each variety throughout the initial 150 days of their productive cycle. The NDVI data was collected with 90, 120 and 150 days after planting (DAP). A descriptive statistical analysis of the data was performed and a Tukey test was applied to contrast the NDVI means. Results indicated that the varieties interfere in the NDVI readings and, in general, the readings with 90 DAP were different from those with 120 and 150 DAP, tending to stabilize along time for each variety.
In vitro antifungal activity of plant extracts on Saprolegnia parasitica from cutaneous lesions of rainbow trout (Oncorhynchus mykiss) eggs
Saprolegnia parasitica Coker is the main agent of saprolegniosis, one of the most important cause... more Saprolegnia parasitica Coker is the main agent of saprolegniosis, one of the most important causes of economic losses in the rainbow trout farming industry in Iran. In this work, seven essential oils (2 species) and ethanol extracts (5 species) were tested against a strain of S. parasitica from cutaneous lesions of Oncorhynchus mykiss eggs, using a continuously agitated broth technique that allows both the minimum inhibitory concentration (MIC > 50 % ) and the minimum lethal concentration (MLC > 99.9 % ) to be evaluated. The essential oils of Thymus daenensis and Thymus khuzestanicum (MIC > 50 % = 0.63 µl ml -1 and MLC > 99.9 % = 22 µl ml -1 ) and ethanol extracts of Tanacetum parthenium and Mentha longifolia (MIC > 50 % = 31.25 and 62.5 µg ml-1 and MLC > 99.9 % = 600 and 550 µg ml-1, respectively) showed higher inhibition against S. parasitica than the other extracts. In general, our study suggests that natural products derived from some medicinal plants have the potential to be used as health rainbow trout eggs.
Based on material flows, energy flow assessment evaluates environmental sustainability and energy... more Based on material flows, energy flow assessment evaluates environmental sustainability and energy use efficiency on a production system. As precision agriculture was developed to optimize agricultural production, energy assessment has become an interesting approach to analyze these systems. A method was developed to propitiate energy evaluation on site-specific data from variable rate nitrogen application on precision agriculture management. It provides maps of energy indicators (energy balance, energy return on investment and energy embodiment) from input and output energy flows. Variable and fixed nitrogen applications were evaluated on a wheat production on Paraná state, Brazil. An optical sensor was used to generate variable rate nitrogen prescriptions. Energy balance and profitability was higher on precision agriculture management because it provided nitrogen savings without compromising yield. Besides, less energy was embodied on the final product. All energy indicators pointed to the fact that variable rate technology was more sustainable than traditional management.
Utilização de sensor ótico ativo em culturas de cereais
Gestão da adubação nitrogenada em milho utilizando sensoriamento remoto
Pesquisa Agropecuaria Brasileira, Aug 1, 2008
Resumo -O objetivo deste trabalho foi avaliar, com um sensor ótico ativo, o comportamento do índi... more Resumo -O objetivo deste trabalho foi avaliar, com um sensor ótico ativo, o comportamento do índice de vegetação por diferença normalizada (NDVI -"normalized difference vegetation index"), nas culturas de trigo, triticale, cevada e milho. Cinco experimentos foram conduzidos no Paraná e São Paulo, com variação de classes de solo, doses e fontes de N, e variedades de trigo. As seguintes variáveis foram avaliadas: NDVI, teor de N foliar, matéria seca e produtividade das culturas. Análises de regressões foram realizadas entre as doses de N aplicadas e NDVI, teor de N foliar, matéria seca e produtividade. Análises de correlação entre as variáveis foram realizadas. O trigo, triticale e cevada apresentaram resposta às aplicações de doses crescentes de N, pelo aumento nas leituras do NDVI, no teor de N foliar e na produtividade. Medido pelo sensor ótico ativo utilizado, o NDVI apresenta alto potencial para manejo do N nas culturas do trigo, triticale e cevada, e baixo potencial para a cultura do milho. Há interferência das variedades de trigo nas leituras do sensor ótico ativo.
Ciencia Tecnol Aliment, 2006
A quem a correspondência deve ser enviada RESUMO O conhecimento das pressões de vapor dos compost... more A quem a correspondência deve ser enviada RESUMO O conhecimento das pressões de vapor dos compostos naturais e suas propriedades críticas, de grande interesse para a extração supercrítica e impregnação de polímeros pelo processo supercrítico, é imprescindível para se fazer a modelagem termodinâmica do equilíbrio de fases. No entanto, a escassez de dados experimentais desses compostos, devida à alta volatilidade, ou facilidade à degradação em temperaturas baixas, requer a utilização de métodos especiais. Neste trabalho, determinaram-se as pressões de vapor da curcumina, nicotina, d-limoneno, β-mirceno, citronelal e linalol, através de um método que utiliza medidas de tempo de retenção por cromatografia gasosa. Utilizou-se detector de ionização de chama e coluna em fase estacionária não polar, em condições isotérmicas. O método apresenta vantagens em relação a outros métodos, quanto à rapidez de análise, quantidade e repetibilidade das amostras. Para as determinações das pressões de vapor destes compostos naturais requer-se o conhecimento da temperatura normal de ebulição, ou temperatura de fusão e das pressões de vapor dos homólogos dos compostos analisados. Palavras-chave: cromatografia gasosa, contribuição de grupos, homólogos, pressão de vapor.
Revista Brasileira de Engenharia de Biossistemas, 2009
Active optical sensors are a new approach for site specific nitrogen management on real time and ... more Active optical sensors are a new approach for site specific nitrogen management on real time and they have been successfully used on grain crops. This work consisted in evaluating the behavior of the Normalized Difference Vegetation Index (NDVI) using a commercial active optical sensor on 28 sugarcane varieties, as well as analyzing the temporal behavior of this index for each variety throughout the initial 150 days of their productive cycle. The NDVI data was collected with 90, 120 and 150 days after planting (DAP). A descriptive statistical analysis of the data was performed and a Tukey test was applied to contrast the NDVI means. Results indicated that the varieties interfere in the NDVI readings and, in general, the readings with 90 DAP were different from those with 120 and 150 DAP, tending to stabilize along time for each variety.
Engenharia Agricola, 2011
RESUMO: Pesquisas indicam que o uso de novas técnicas no campo da mecanização agrícola, como o tr... more RESUMO: Pesquisas indicam que o uso de novas técnicas no campo da mecanização agrícola, como o tráfego controlado por meio de direcionamento com auxílio de Sistemas de Navegação Global por Satélites (GNSS), pode diminuir as exigências por energia associadas às operações de campo e aumentar a produtividade da mão de obra e da cultura. Alguns autores já utilizaram diferentes metodologias para avaliar erros de paralelismo em sistemas de orientação de veículos, porém não há um procedimento-padrão para medi-los. Sendo assim, o objetivo deste trabalho foi implementar uma planilha eletrônica específica, determinar e comparar a acurácia no paralelismo de dois sistemas distintos de orientação de veículos (uma barra de luz e um piloto automático com atuador de volante) em trajetórias retilíneas e utilizando sinal de GPS com dois sistemas de correção diferencial (um com algoritmo interno e outro, um sinal via satélite com acurácia submétrica). Para a avaliação dos sistemas de correção, utilizou-se como referência o sinal de correção diferencial RTK (Real Time Kinematic) para realização de cinco passadas paralelas sucessivas para cada sistema de correção, caracterizando cinco repetições de cada tratamento. A planilha viabilizou o método de avaliação utilizado e os erros apresentados para as correções nos dois equipamentos analisados mostraram-se compatíveis com operações que exijam acurácia de paralelismo da ordem de decímetros.
Optical Sensors - New Developments and Practical Applications, 2014
Pesquisa Agropecuária Brasileira
The objective of this work was to evaluate the behavior of the normalized difference vegetation i... more The objective of this work was to evaluate the behavior of the normalized difference vegetation index (NDVI), with an active optical sensor, in wheat, triticale, barley and corn crops. Experiments were conducted in Paraná and São Paulo, comparing different soil classes, N rates and sources, and wheat varieties. The following variables were determined: NDVI, N foliar content, dry mass and crop yield. Regression analyses were performed between NDVI and applied N rates, N foliar content, dry mass and yield. Correlation analyses among the variables were performed. Wheat, triticale and barley crops showed response to increasing N rates by the increase in the NDVI readings, to N foliar content and to yield. Measured by the used active optical sensor the NDVI shows high potential for N management wheat, triticale and barley crops, and low potential for corn crops. There is interference of wheat varieties in the active optical sensor's readings.
Engenharia Agrícola
Activities that use Global Navigation Satellite System (GNSS) are countless and the most used one... more Activities that use Global Navigation Satellite System (GNSS) are countless and the most used one is the Global Positioning System (GPS) developed by the United States. In precision agriculture there are demands for static and cinematic positioning with distinct levels of accuracy for different applications; nevertheless cinematic performance data are not available as manufacturers of GPS receivers present only static performance information. For this reason it was developed an instrumented vehicle to test a methodology of performance evaluation of GPS receivers in kinematic conditions, which is representative to agricultural operations. A set of instrumentation was composed and used for collecting data under variable speed and rotation direction. Tests were conducted showing that the methodology allows to measure accuracy and precision, but improvements have to be implemented on the instrumentation equipment for long term tests.
Based on material flows, energy flow assessment evaluates environmental sustainability and energy... more Based on material flows, energy flow assessment evaluates environmental sustainability and energy use efficiency on a production system. As precision agriculture was developed to optimize agricultural production, energy assessment has become an interesting approach to analyze these systems. A method was developed to propitiate energy evaluation on site-specific data from variable rate nitrogen application on precision agriculture management. It provides maps of energy indicators (energy balance, energy return on investment and energy embodiment) from input and output energy flows.
Revista Brasileira de Engenharia Agrícola e Ambiental
Techniques of precision agriculture are alternatives to optimize the use of inputs, among them ni... more Techniques of precision agriculture are alternatives to optimize the use of inputs, among them nitrogen. The present work had as its objective to verify the possibility of use of a commercial optical sensor in sugarcane, verifying its capability in identification of the crop response to different nitrogen (N) rates. An experiment was installed in randomized blocks in an experimental area with third sugarcane ratoon, harvested mechanically, with different N rates (0, 50, 100, 150 and 200 kg ha-1) and four repetitions. At 30, 60 and 90 days after the harvest (DAH) the measuring of NDVI (normalized difference vegetation index) was accomplished starting from the optical sensor. No response was verified of NDVI on measurements at the 30 and 60 DAH, however at 90 DAH the sensor was capable to differentiate the doses of applied N, positively correlated with the sugarcane final production. This work gives subsidies to studies of same nature that seek the management of the nitrogen fertiliza...
Revista Brasileira de Engenharia Agrícola e Ambiental, 2010
Técnicas de agricultura de precisão são alternativas para otimizar a utilização de insumos, dentr... more Técnicas de agricultura de precisão são alternativas para otimizar a utilização de insumos, dentre eles o nitrogênio. O presente trabalho teve como objetivo verificar a possibilidade de uso de um sensor ótico ativo comercial na cultura da cana-de-açúcar, verificando sua capacidade em identificar a resposta da cultura a diferentes doses de nitrogênio (N). Para tanto um experimento em blocos ao acaso foi instalado em área experimental de cana-de-açúcar de terceiro corte, colhida mecanicamente, com diferentes doses de N (0, 50, 100, 150 e 200 kg ha -1 ) e quatro repetições. Aos 30, 60 e 90 dias após o corte (DAC) realizou-se a mensuração do NDVI (índice de vegetação por diferença normalizada) a partir do sensor ótico. Não se obteve resposta do NDVI mensurado aos 30 e 60 DAC, porém aos 90 DAC se verificou que o sensor foi capaz de diferenciar as doses de N aplicadas, correlacionando-se positivamente com a produtividade final de colmos obtida. Este trabalho dá subsídios a trabalhos de mesma natureza que visem a gestão da adubação nitrogenada em cana-de-açúcar a partir de sensores óticos.
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Papers by Fabricio P Povh