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| Vieira,Renan Costa Beber; Fontoura,Sandra Mara Vieira; Bayer,Cimélio; Moraes,Renato Paulo de; Carniel,Eduardo. |
| ABSTRACT Fertilization programs for annual crops in the state of Paraná, southern Brazil, are based on studies that focused on conventional tillage and were established more than 30 years ago. The primary purpose of this study was to assess potassium (K) fertilization on long-term (>30 years) no-tillage soybean, corn, wheat, and barley crops grown in rotation on Oxisols in the central-southern region of Paraná. A total of 47 experiments were carried out from 2008 to 2013, three of which addressed K calibration and the other 44, crop response to K fertilization. Critical K soil-test value and interpretation classes were established from the ratio between relative crop yield [RY = (yield without K/max yield) × 100] and soil K levels. Winter cereals were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Critical level; Mehlich-1. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100538 |
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| Saretta,Ezequiel; Camargo,Antonio P. de; Botrel,Tarlei A.; Pinto,Marinaldo F.; Katsurayama,Geancarlo T.; Frizone,José A.. |
| ABSTRACT Current meters are equipment widely used for estimating flow velocity in rivers and streams. Periodic calibrations of current meters are important to ensure the quality of measurements, but the required testing facilities are complex and only available in a few institutions. However, advances in electronics and automation may contribute to developing simple and reliable calibration systems. Thus, this study aimed to develop an automated system for testing current meters, which consisted of a trapezoidal channel, a step motor, a tow car and a management system, composed of a supervisory application and microprocessed modules to control the motor and the data acquisition. Evaluations of the displacement velocity showed that it matched the reference... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hydrometry; Electronics; Automation; Calibration. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000200181 |
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| Ercanli,Ilker; Gunlu,Alkan; Başkent,Emin Zeki. |
| Diameter at breast height (DBH) is the simplest, most common and most important tree dimension in forest inventory and is closely correlated with wood volume, height and biomass. In this study, a number of linear and nonlinear models predicting diameter at breast height from stump diameter were developed and evaluated for Oriental beech (Fagus orientalisLipsky) stands located in the forest region of Ayancık, in the northeast of Turkey. A set of 1,501 pairs of diameter at breast height-stump measurements, originating from 70 sample plots of even-aged Oriental beech stands, were used in this study. About 80 % of the otal data (1,160 trees in 55 sample plots) was used to fit a number of linear and nonlinear model parameters; the remaining 341 trees in 15... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: DBH; Prediction; Random parameters; Calibration. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162015000300245 |
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| Rigon, João Paulo Gonsiorkiewicz; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Capuani, Silvia; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Beltrão, Napoleão de Esberard Macêdo; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Brito Neto, José Félix; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista; Sofiatti, Valdinei; Empresa Brasileira de Pesquisa Agropecuária; França, Fabíola Vanessa; Faculdade de Ciências Agronômicas, Universidade Estadual Paulista. |
| The aim of the present work was to determine the relationship between photosynthetic pigments extracted in dimethyl sulfoxide (DMSO) and readings obtained by the portable chlorophyll meter, ClorofiLOG® 1030, to generate mathematical models that are able to report the contents of chlorophyll and carotenoids in the leaves of the castor oil plant. This work was conducted at Embrapa Cotton, located in the city of Campina Grande, state of Paraíba, Brazil, in October 2010. For the indirect analysis, portable equipment was used to read leaf discs of different shades of green. The chlorophyll in these discs was then determined using a classical method: 5 mL of DMSO was added, the samples were incubated in a water bath at 70ºC for 30 minutes, and a 3 mL aliquot was... |
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Palavras-chave: 5.01.00.00-9 chlorophyll meter; Calibration; Chlorophyll 5.01.03.00-8. |
| Ano: 2012 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/13872 |
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| Amirouche, mawhoub. |
| The search for decision-making tools is essential in order to control agricultural practices and plan for sustainable agriculture that respects the environment. To this end, FAO has developed an evaluation model called AquaCrop, which covers most technical routes, including fertilization. In this perspective, this study focuses on the AquaCrop model (v6.1) to calibrate it for the simulation of lettuce crop yields (Lactuca sativa L), under different fertilization levels for the trial periods (2015/2016) and (2016/2017). Four levels of fertilization were examined under rain conditions, namely T1 (0 kg N/ha), T2 (60 kg N/ha), T3 (120 kg N/ha) and T4 (180 kg N/ha). The model performance was evaluated using the coefficient of determination (R2), the square root... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: AquaCrop; Lettuce; Calibration; Validation; Fertility stress; Water productivity. |
| Ano: 2021 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/6195 |
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| SAHACHAIRUNGRUENG, WORANITTA; TEERACHAICHAYUT, SONTISUK. |
| Near infrared hyperspectral imaging (NIR-HSI) is a method that can be used to evaluate quality of fruit nondestructively. The objective of this research was to study the feasibility of NIR-HSI reflectance mode, within the wavelength of 935-1720 nm, for predicting quality of longans. The two important factors chosen were: total soluble solids (TSS) and moisture content (MC). Each longan was assessed by first measuring its spectral data then measuring its TSS and MC to establish calibration models using multiple linear regression (MLR) compared with partial least squares regression (PLSR). Original spectra of longans gave the optimum results by PLSR for developing the models with correlation coefficients (Rp) of 0.76 for TSS and 0.88 for MC as well as root... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spectra; Nondestructive; Calibration; Prediction; Images. |
| Ano: 2022 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7203 |
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| VASCONCELOS,PAULO M.; ONOE,ARTUR T.; KAWASHITA,KOJI; SOARES,ADALBERTO J.; TEIXEIRA,WILSON. |
| Laser heating 40Ar/39Ar geochronology provides high analytical precision and accuracy, mum-scale spatial resolution, and statistically significant data sets for the study of geological and planetary processes. A newly commissioned 40Ar/39Ar laboratory at CPGeo/USP, São Paulo, Brazil, equips the Brazilian scientific community with a new powerful tool applicable to the study of geological and cosmochemical processes. Detailed information about laboratory layout, environmental conditions, and instrumentation provides the necessary parameters for the evaluation of the CPGeo/USP 40Ar/39Ar suitability to a diverse range of applications. Details about analytical procedures, including mineral separation, irradiation at the IPEN/CNEN reactor at USP, and mass... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geochronology; 40Ar/39Ar method; Irradiation; Calibration. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000200008 |
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| SILVA JÚNIOR,RENATO O. DA; SOUZA,EVERALDO B. DE; TAVARES,ALEXANDRA L.; MOTA,JOSÉ A.; FERREIRA,DOUGLAS B.S.; SOUZA-FILHO,PEDRO W.M.; ROCHA,EDSON J.P. DA. |
| ABSTRACT This study estimated the reference evapotranspiration rate (ETo) for the Itacaiúnas River Watershed (IRW), Eastern Amazonia, and measured the accuracy of eight empirical equations: Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves and Samani (HS), Camargo (CAM), Thornthwaite (TH), Hamon (HM), Kharrufa (KF) and Turc (TC) using monthly data from 1980 to 2013. In addition, it verifies the regional applicability to the IRW using a for the Marabá-PA station. The methods TC and PM (FAO56) presented the best results, which demonstrate that radiation and higher temperatures are the dominant drivers in the Evapotranspiration process, while relative humidity and wind speed have a much smaller impact. The temporal and spatial variability of ETo for IRW... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Decades; Eastern Amazon; Evapotranspiration; Methods; Watershed. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652017000501985 |
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| Machado,Nicácia P.; Fachinello,José C.; Galarça,Simone P.; Betemps,Débora L.; Pasa,Mateus S.; Schmitz,Juliano D.. |
| Recently, non-destructive techniques such as the Vis / NIR spectroscopy have been used to evaluate the characteristics of maturation and quality of pears. The study aims to validate the readings by the Vis / NIR spectroscopy as a non-destructive way to assess the qualitative characteristics of pear cultivars 'Williams', 'Packams' and 'Carrick', produced according to Brazilian conditions. The experiment was conducted at the Pelotas Federal University, UFPel, in Pelotas / RS, and the instrument used to measure the fruit quality in a non-destructive way was the NIR- Case spectrophotometer (SACMI, Imola, Italy). To determine pears' soluble solids (SS) and pulp firmness (PF), it was established calibration equations for each variety studied, done from the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Firmness; Pear; Soluble solids; Validation. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000300027 |
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| Rodríguez,N.M.; Campos,W.E.; Lachica,M.L.; Borges,I.; Gonçalves,L.C.; Borges,A.L.C.C.; Saliba,E.O.S.. |
| An indirect calorimetry system for rapid determination of CO2 and CH4 production and O2 consumption to estimate heat production of animals was built at Escola de Veterinária da Universidade Federal de Minas Gerais, Brazil. Procedures for determination of correction and calibration factors for gas analyzers and the whole system, using standard test gases were described. In addition, a metabolic trial was performed to evaluate heat production of lambs fed ad libitum. It is concluded that the system is suitable for heat production determinations in small and medium size animals. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Open circuit; Respirometry. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352007000200033 |
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| Rodrigues,Rafael de Ávila; Pedrini,João Eduardo; Fraisse,Clyde William; Fernandes,José Maurício Cunha; Justino,Flávio Barbosa; Heinemann,Alexandre Bryan; Costa,Luiz Cláudio; Vale,Francisco Xavier Ribeiro do. |
| In recent years, crop models have increasingly been used to simulate agricultural features. The DSSAT (Decision Support System for Agrotechnology Transfer) is an important tool in modeling growth; however, one of its limitations is related to the unaccounted-for effect of diseases. Therefore, the goals of this study were to calibrate and validate the CSM CROPGRO-Soybean for the soybean cultivars M-SOY 6101 and MG/BR 46 (Conquista), analyze the performance and the effect of Asian soybean rust on these cultivars under the environmental conditions of Viçosa, Minas Gerais, Brazil. The experimental data for the evaluation, testing, and adjustment of the genetic coefficients for the cultivars, M-SOY 6101 and MG/BR 46 (Conquista), were obtained during the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: DSSAT; Calibration; Validation; Modeling; Rust epidemics. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052012000200021 |
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| Heinemann,Alexandre Bryan; van Oort,Pepijn A.J.; Fernandes,Diogo Simões; Maia,Aline de Holanda Nunes. |
| Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs) data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI) and total accumulated solar radiation (SRA) during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation),... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Crop model; Calibration; Upland rice. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052012000400016 |
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| Lazzaretti,Bruno Pedro; Silva,Leandro Souza da; Drescher,Gerson Laerson; Dotto,André Carnieletto; Britzke,Darines; Nörnberg,José Laerte. |
| ABSTRACT: Among the soil constituents, special attention is given to soil organic matter (SOM) and clay contents, since, among other aspects, they are key factors to nutrient retention and soil aggregates formation, which directly affect the crop production potential. The methods commonly used for the quantification of these constituents have some disadvantages, such as the use of chemical reactants and waste generation. An alternative to these methods is the near-infrared spectroscopy (NIRS) technique. The aim of this research is to evaluate models for SOM and clay quantification in soil samples using spectral data by NIRS. A set (n = 400) of soil samples previously analyzed by traditional methods were used to generate a NIRS calibration curve. The clay... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Validation; Mathematical models; Spectral pretreatment.. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782020000100251 |
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| Registros recuperados: 60 | |
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