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15N-labeled glyphosate synthesis and its practical effectiveness Scientia Agricola
Tavares,Claudinéia Raquel de Oliveira; Bendassolli,José Albertino; Ribeiro,Daniela Neves; Rossete,Alexssandra Luiza Rodrigues Molina.
Glyphosate is the herbicide with the greatest participation in the world market, and it has been used intensively in agriculture for over 30 years, especially because of its relatively low cost and high effectiveness on different species. This study describes a synthesis method of glyphosate in the form of the isopropylamine salt enriched in the stable nitrogen isotope (15N). The 15N-herbicide synthesis was performed using a phosphomethylation reaction with dialkyl phosphite and 15N-glycine. The tests were conducted at a microscale and equimolar quantities. A 20% yield was obtained at the established conditions. To test the effectiveness of the synthesized glyphosate, an experiment was performed in a growth chamber with the weed Lolium multiflorum...
Tipo: Info:eu-repo/semantics/report Palavras-chave: Lolium multiflorum; Isopropylamine salt; Stable isotope.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000100014
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15N-labeled nitrogen from green manure and ammonium sulfate utilization by the sugarcane ratoon Scientia Agricola
Ambrosano,Edmilson José; Trivelin,Paulo Cesar Ocheuze; Cantarella,Heitor; Ambrosano,Gláucia Maria Bovi; Schammass,Eliana Aparecida; Muraoka,Takashi; Rossi,Fabrício.
Legumes as green manure are alternative sources of nitrogen (N) for crops and can supplement or even replace mineral nitrogen fertilization due to their potential for biological nitrogen fixation (BNF). The utilization of nitrogen by sugarcane (Saccharum spp.) fertilized with sunn hemp (Crotalaria juncea L.) and ammonium sulfate (AS) was evaluated using the 15N tracer technique. N was added at the rate of 196 and 70 kg ha-1 as 15Nlabeled sunn hemp green manure (SH) and as ammonium sulfate (AS), respectively. Treatments were: (i) Control; (ii) AS15N; (iii) SH15N + AS; (iv) SH15N; and (v) AS15N + SH. Sugarcane was cultivated for five years and was harvested three times. 15N recovery was evaluated in the two first harvests. In the sum of the three harvests,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Saccharum spp.; Brazil; Sunn hemp; Isotope technique.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000300014
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24-h variation in soil respiration after a long dry season in a Sudano-Sahelian region Scientia Agricola
Yemadje,Pierrot Lionel; Guibert,Hervé; Blavet,Didier; Olina,Jean-Paul; Chevallier,Tiphaine; Deleporte,Philippe; Bernoux,Martial.
Soil respiration is a major component of the global carbon cycle which links ecosystems and the atmosphere. To evaluate the reaction of soil respiration after wetting, during a dry period, soil respiration and associated environmental factors were measured over a 24-h period, during the dry season in North Cameroon after wetting the soil. Over 24-h, soil respiration rates followed a quadratic curve during the day coming close to linear at night, while soil temperature and moisture together explained at least 73 % of the variations during the 24-h observed. These soil respiration rates increased during the morning, peaked between 11h00 and 13h00 and then decreased gradually to the minimum around 06h00. These observations were used to propose a method for...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Diel soil respiration; Soil temperature; Soil moisture.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162015000500452
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A brief review of soil water, solute transport and regionalized variable analysis Scientia Agricola
Nielsen,D.R.; Hopmans,J.W.; Kutílek,M.; Wendroth,O..
We initially review basic concepts of the forces acting on soil water, soil water potential and soil water retention, and equations to describe soil water movement under water-saturated and unsaturated conditions. Processes of infiltration, evaporation and redistribution of water will be presented for simple initial and boundary conditions occurring within homogeneous soil columns. Next we consider the physical, chemical and biological processes within a soil profile that distribute, dilute or concentrate solute species within the liquid phase of a soil The relative concentration of solutes in the liquid phase governs not only the retention and transport of water within soils but also contributes to our understanding of managing the quality of water within...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Solute transport; Regionalized variable.
Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161997000300012
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A comparison between Joint Regression Analysis and the Additive Main and Multiplicative Interaction model: the robustness with increasing amounts of missing data Scientia Agricola
Rodrigues,Paulo Canas; Pereira,Dulce Gamito Santinhos; Mexia,João Tiago.
This paper joins the main properties of joint regression analysis (JRA), a model based on the Finlay-Wilkinson regression to analyse multi-environment trials, and of the additive main effects and multiplicative interaction (AMMI) model. The study compares JRA and AMMI with particular focus on robustness with increasing amounts of randomly selected missing data. The application is made using a data set from a breeding program of durum wheat (Triticum turgidum L., Durum Group) conducted in Portugal. The results of the two models result in similar dominant cultivars (JRA) and winner of mega-environments (AMMI) for the same environments. However, JRA had more stable results with the increase in the incidence rates of missing values.
Tipo: Info:eu-repo/semantics/article Palavras-chave: AMMI models; Genotype by environment interaction; Joint regression analysis; Missing values; Durum wheat.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000600012
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A cost prediction model for machine operation in multi-field production systems Scientia Agricola
Sopegno,Alessandro; Busato,Patrizia; Berruto,Remigio; Romanelli,Thiago Libório.
ABSTRACT Capacity planning in agricultural field operations needs to give consideration to the operational system design which involves the selection and dimensioning of production components, such as machinery and equipment. Capacity planning models currently onstream are generally based on average norm data and not on specific farm data which may vary from year to year. In this paper a model is presented for predicting the cost of in-field and transport operations for multiple-field and multiple-crop production systems. A case study from a real production system is presented in order to demonstrate the model’s functionalities and its sensitivity to parameters known to be somewhat imprecise. It was shown that the proposed model can provide operation cost...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Machinery management; Decision support system; Strategic management; Binary programming.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162016000500397
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A critical survey of optimization methods in industrial forest plantations management Scientia Agricola
Belavenutti,Pedro; Romero,Carlos; Diaz-Balteiro,Luis.
ABSTRACT: The application of optimization methods to forest management has given rise to a successful line of investigation in recent decades. However, there have been few publications associated with the application of these techniques to the management of industrial forest plantations (those with short or medium rotations, always less than 50 years), which consider the important role played by these forest systems in the supply of diverse goods and services. This study presents an overview of this literature which, by analyzing 67 articles published in journals contained in the ISI Web of Science, highlight, among other aspects, the techniques employed, their evolution, their planning type (strategic, tactical or operational), the functional objectives...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Mathematical programming; Forest management; Industrial plantations; Timber harvest scheduling.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000300239
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A crop model-based approach for sunflower yields Scientia Agricola
Leite,João Guilherme Dal Belo; Silva,João Vasco; Justino,Flávio Barbosa; Ittersum,Martin K. van.
Pushed by the Brazilian biodiesel policy, sunflower (Helianthus annuus L.) production is becoming increasingly regarded as an option to boost farmers' income, particularly under semi-arid conditions. Biodiesel related opportunities increase the demand for decision-making information at different levels, which could be met by simulation models. This study aimed to evaluate the performance of the crop model OILCROP-SUN to simulate sunflower development and growth under Brazilian conditions and to explore sunflower water- and nitrogen-limited, water-limited and potential yield and yield variability over an array of sowing dates in the northern region of the state of Minas Gerais, Brazil. For model calibration, an experiment was conducted in which two...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Production systems; Family farms; Biodiesel crops; Climate classification.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162014000500001
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A decision-tree-based model for evaluating the thermal comfort of horses Scientia Agricola
Maia,Ana Paula de Assis; Oliveira,Stanley Robson de Medeiros; Moura,Daniella Jorge de; Sarubbi,Juliana; Vercellino,Rimena do Amaral; Medeiros,Brenda Batista Lemos; Griska,Paulo Roberto.
Thermal comfort is of great importance in preserving body temperature homeostasis during thermal stress conditions. Although the thermal comfort of horses has been widely studied, there is no report of its relationship with surface temperature (T S). This study aimed to assess the potential of data mining techniques as a tool to associate surface temperature with thermal comfort of horses. T S was obtained using infrared thermography image processing. Physiological and environmental variables were used to define the predicted class, which classified thermal comfort as "comfort" and "discomfort". The variables of armpit, croup, breast and groin T S of horses and the predicted classes were then subjected to a machine learning process. All variables in the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Feature selection methods; Data mining; Surface temperature; Infrared thermography; Thermoregulation.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162013000600001
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A hydropedological approach to a mountainous Clayey Humic Dystrudept in the Mantiqueira Range, southeastern Brazil Scientia Agricola
Pinto,Leandro Campos; Mello,Carlos Rogério de; Norton,Lloyd Darrell; Poggere,Giovana Clarice; Owens,Phillip Ray; Curi,Nilton.
ABSTRACT: The Mantiqueira Range region is one of the most important headwaters in southeastern Brazil. In this context, the relationship between pedology and hydrology has been debated and analyzed in recent years, contributing to the creation of a multidisciplinary science call hydropedology. Therefore, the aim of this study was to evaluate the hydropedological properties of a mountainous Clayey Humic Dystrudept in the Mantiqueira Range region, in the state of Minas Gerais, Brazil, comparing two land-uses, native forest and pasture. The hydraulic conductivity results demonstrated that native forest (MFO) has a strong influence on this parameter, offering conditions for movement of water in the soil that are more adequate in this profile than in pasture....
Tipo: Info:eu-repo/semantics/article Palavras-chave: S index; Saturated hydraulic conductivity; Soil pore size distribution; Soil erosion; Water quality.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000100060
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A leaf bud technique for rapid propagation of cassava (Manihot esculenta Crantz) Scientia Agricola
Neves,Reizaluamar de Jesus; Souza,Leonardo Silva; Oliveira,Eder Jorge de.
ABSTRACT The slow rate of multiplication is one of the main constraints on the production of cassava (Manihot esculenta Crantz). This work aimed to evaluate the use of leaf buds for rapid propagation of cassava varieties. Leaf buds were excised from three cassava varieties (BRS Kiriris, 98150-06 and 9624-09) for plantlet generation. The experiment was completely randomized with a 5 (age of mother plant) × 3 (position of the leaf buds on the stems) × 2 (agrochemical treatments) factorial design. Data were collected on leaf sprouting percentage (Spro.Per), plantlet height (Plant.Hei) and total dry mass of plantlets (Dry.Mass.Plant). There was a difference between the three traits for most of the varieties, demonstrating significant effects on the agronomic...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Sprouting; Cuttings; Alternative multiplication; Asexual propagation.
Ano: 2020 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000200600
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A lima bean core collection based on molecular markers Scientia Agricola
Gomes,Regina Lucia Ferreira; Costa,Marcones Ferreira; Alves-Pereira,Alessandro; Bajay,Miklos Maximiliano; Viana,João Paulo Gomes; Valente,Sérgio Emílio dos Santos; Lopes,Ângela Celis de Almeida; Zucchi,Maria Imaculada; Pinheiro,José Baldin.
ABSTRACT Some germplasm collections have a high number of accessions, which makes it difficult to explore the genetic variability present in the germplasm bank due to the redundancy and the difficulty of detailed analysis of all conserved accessions. Therefore, our study aimed to analyze the genetic diversity of 153 lima bean (Phaseolus lunatus) accessions for the purpose of constructing a core collection. Eleven SSRs were used for this purpose. The 153 lima bean accessions can be represented by low redundancy using a minimum of 34 accessions, thus representing 22 % of the size of the entire germplasm bank. The core collection had a higher Shannon diversity index and expected heterozygosity (1.906 and 0.811, respectively) than those presented by the entire...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Germplasm; Genetic diversity; Genetic structure; Microsatellite markers.
Ano: 2020 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000201100
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A methodology to determine size and shape of plots for sugarcane plantation Scientia Agricola
Cherri,Adriana Cristina; Vianna,Andrea Carla Gonçalves; Ramos,Rômulo Pimentel; Florentino,Helenice de Oliveira.
ABSTRACT: Brazil is the largest sugarcane producer in the world and the leader in the production of sugar and ethanol. Although sugarcane has become an important factor in the Brazilian economy, cultivation has presented many issues, for example, the problems due to burning before the manual harvest. The Brazilian authorities have approved a law that prohibits this practice and mechanized harvesting has thus become the most fitting approach. Given this development, areas for sugarcane plantation must be properly rebuilt to accommodate the new way of harvesting. The main characteristic demanded of sugarcane plots to use harvesting machines is that they must be rectangular. In the present paper, we propose a methodology for dividing the plantation area into...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Planting planning; Sugarcane culture; Mechanized harvesting; AND/OR graph approach.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162019001400266
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A model to explain high values of pH in an alkali sodic soil Scientia Agricola
Guerrero-Alves,José; Pla-Sentís,Ildefonso; Camacho,Rafael.
For alkali sodic soils (pH>8.5), the "hydrolysis of exchangeable sodium" has been used as a possible explanation for the alkalinity production and rise in pH of these soils. As an alternative to this hypothesis, a model was developed to simulate and to explain that the alkalinity production and rise in pH is possible in a soil that accumulates alkaline sodium salts and CaCO3. Several simulations were performed by using different combinations of CO2 partial pressures (P), presence or absence of MgCO3, along with experimental values of exchangeable sodium percentage (ESP) and ion concentrations in saturation extracts from an alkali sodic soil (named Pantanal). A hypothetical system with similar conditions to the Pantanal soil but with a Gapon selectivity...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Gapon selectivity coefficients; Calcium carbonate; Sodium bicarbonate; Alkaline hydrolysis.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000400021
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A prática pedagógica do professor de Engenharia Agronômica Scientia Agricola
Tullio,A. A..
Esta pesquisa procurou identificar a prática pedagógica do professor de Engenharia Agronômica, quais as concepções do processo de aprendizagem e em que medida o conceito teórico do professor é coerente com a sua prática. A prática pedagógica foi aqui delimitada como sendo o cotidiano do professor na execução de seu ensino. O público alvo foram os docentes e discentes do Curso de Engenharia Agronômica da Escola Superior de Agricultura "Luiz de Queiroz"- Campus de Piracicaba da USP. O método expositivo foi predominante, apoiado no uso do quadro negro e retroprojetor. O professor nesse método é a figura central do processo ensino-aprendizagem. A freqüência bastante acentuada em Congressos tem trazido uma atualização constante em termos de conteúdo.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Agronomia; Ensino; Pedagogia.
Ano: 1995 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161995000300029
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A rapid method for measuring soil water content in the field with a areometer Scientia Agricola
Calbo,Adonai Gimenez.
The availability of a rapid method to evaluate the soil water content (U) can be an important tool to determine the moment to irrigate. The soil areometer consists of an elongated hydrostatic balance with a weighing pan, a graduated neck, a float and a pynometric flask. In this work an areometer was adapted to rapidly measure soil water content without the need of drying the soil. The expression U = (M A - M AD)/(M M -M A) was used to calculate the soil water content. In this equation M M is the mass to level the areometer with the pycnometric flask filled with water, M A the mass to level the areometer with a mass M M of soil in the pycnometer, the volume being completed with water, and similarly M AD the mass added to the pan to level the areometer with...
Tipo: Info:eu-repo/semantics/report Palavras-chave: Hydrostatic balance; Irrigation moment; Pycnometer; Soil humidity.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000400029
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A simple method for DNA isolation from Xanthomonas spp. Scientia Agricola
Gomes,Luiz Humberto; Duarte,Keila Maria Roncato; Andrino,Felipe Gabriel; Tavares,Flavio Cesar Almeida.
A simple DNA isolation method was developed with routine chemicals that yields high quality and integrity preparations when compared to some of the most well known protocols. The method described does not require the use of lysing enzymes, water bath and the DNA was obtained within 40 minutes The amount of nucleic acid extracted (measured in terms of absorbancy at 260 nm) from strains of Xanthomonas spp., Pseudomonas spp. and Erwinia spp. was two to five times higher than that of the most commonly used method.
Tipo: Info:eu-repo/semantics/report Palavras-chave: DNA; Xanthomonas; RAPD.
Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162000000300028
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A simplified Excel® algorithm for estimating the least limiting water range of soils Scientia Agricola
Leão,Tairone Paiva; Silva,Alvaro Pires da.
The least limiting water range (LLWR) of soils has been employed as a methodological approach for evaluation of soil physical quality in different agricultural systems, including forestry, grasslands and major crops. However, the absence of a simplified methodology for the quantification of LLWR has hampered the popularization of its use among researchers and soil managers. Taking this into account this work has the objective of proposing and describing a simplified algorithm developed in Excel® software for quantification of the LLWR, including the calculation of the critical bulk density, at which the LLWR becomes zero. Despite the simplicity of the procedures and numerical techniques of optimization used, the nonlinear regression produced reliable...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nonlinear regression; Spreadsheet software; Optimization; Soil physics; Soil quality.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000600013
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A smartphone-based apple yield estimation application using imaging features and the ANN method in mature period Scientia Agricola
Qian,Jianping; Xing,Bin; Wu,Xiaoming; Chen,Meixiang; Wang,Yan'an.
ABSTRACT: Apple yield estimation using a smartphone with image processing technology offers advantages such as low cost, quick access and simple operation. This article proposes distribution framework consisting of the acquisition of fruit tree images, yield prediction in smarphone client, data processing and model calculation in server client for estimating the potential fruit yield. An image processing method was designed including the core steps of image segmentation with R/B value combined with V value and circle-fitting using curvature analysis. This method enabled four parameters to be obtained, namely, total identified pixel area (TP), fitting circle amount (FC), average radius of the fitting circle (RC) and small polygon pixel area (SP). A...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Potential yield prediction model; Image processing; Mobile phone application development; Orchard precision management.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162018000400273
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A statistical basis for selecting parameters for the evaluation of soil penetration resistance Scientia Agricola
Leão,Tairone Paiva; Silva,Álvaro Pires da.
Measurements of soil penetration resistance (SR) have been frequently used for the evaluation of soil structural quality for plant growth. However, different data analysis approaches have been used, without a previous evaluation of their statistical quality. In this study we tested the hypothesis that the mean is the parameter with best statistical properties to evaluate alterations in soil penetration resistance in response to soil use and management, as compared to other SR statistical parameters. Undisturbed (5 × 5 cm) soil cores were collected from three sampling sites with different degrees of compaction: an undisturbed site under native scierophylous forest (NC); a site under short-duration grazing with post-grazing residue maintained at 2.0 to 2.5...
Tipo: Info:eu-repo/semantics/article Palavras-chave: LSD; Probit analysis; Means comparison test; Soil physical quality assessment.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000600007
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