SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

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...

Chanter model: nonlinear modeling of the fruit growth of cocoa

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

Silva,Pollyane Vieira da; Savian,Taciana Villela.

ABSTRACT: The growth of plants and animals can be described through a growth curve. This curve is given by the equation of a nonlinear model, such as the Logistic model and the Gompertz model. The objective of this study was to adjust the Chanter model, as well as Logistic and Gompertz, using a set of cocoa (clone Sial-105) fruit whose length and diameter measurements were evaluated from 30 to 180 days after pollination, every 15 days. The Chanter model is a hybrid between the Logistic model and Gompertz model whose parameters can be interpreted similarly. A comparison of the quality of fit between the models was made using the following statistical measures: the Akaike’s information criterion (AIC), the Akaike’s weights criterion, Bayesian information...

Critical points in logistic growth curves and treatment comparisons

Palavras-chave: Nonlinear regression; Chanter model; Nonlinearity and cocoa fruits measures.

Ano: 2019

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019001100407

Passos,José Raimundo de Souza; Pinho,Sheila Zambello de; Carvalho,Lídia Raquel de; Mischan,Martha Maria.

Several biological phenomena have a behavior over time mathematically characterized by a strong increasing function in the early stages of development, then by a less pronounced growth, sometimes showing stability. The separation between these phases is very important to the researcher, since the maintenance of a less productive phase results in uneconomical activity. In this report we present methods of determining critical points in logistic functions that separate the early stages of growth from the asymptotic phase, with the aim of establishing a stopping critical point in the growth and on this basis determine differences in treatments. The logistic growth model is fitted to experimental data of imbibition of araribá seeds (Centrolobium tomentosum)....

Determination of a point sufficiently close to the asymptote in nonlinear growth functions

Palavras-chave: Nonlinear regression; Asymptotic regression; Stopping critical level; Seeds imbibition.

Ano: 2012

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000500004

Mischan,Martha Maria; Pinho,Sheila Zambello de; Carvalho,Lídia Raquel de.

Growth functions with upper horizontal asymptote do not have a maximum point, but we frequently question from which point growth can be considered practically constant, that is, from which point the curve is sufficiently close to its asymptote, so that the difference can be considered non-significant. Several methods have been employed for this purpose, such as one that verifies the significance of the difference between the curve and its asymptote using a t-test, and that of Portz et al. (2000), who used segmented regression. In the present work, we used logistic growth function, which has horizontal asymptote and one inflection point, and applied a new method consisting in the mathematical determination of a point in the curve from which the growth...

Determination of the critical period of weed control in corn using a thermal basis

Palavras-chave: Nonlinear regression; Logistic model; Critical point of growth.

Ano: 2011

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162011000100016

PAB

Bedmar,Francisco; Manetti,Pablo; Monterubbianesi,Gloria.

Field studies were conducted over 3 years in southeast Buenos Aires, Argentina, to determine the critical period of weed control in maize (Zea mays L.). The treatments consisted of two different periods of weed interference, a critical weed-free period, and a critical time of weed removal. The Gompertz and logistic equations were fitted to relative yields representing the critical weed-free and the critical time of weed removal, respectively. Accumulated thermal units were used to describe each period of weed-free or weed removal. The critical weed-free period and the critical time of weed removal ranged from 222 to 416 and 128 to 261 accumulated thermal units respectively, to prevent yield losses of 2.5%. Weed biomass proved to be inverse to the crop...

Drying kinetics of jabuticaba pulp by regression models

Palavras-chave: Weed interference; Weed management; Accumulated thermal units; Nonlinear regression.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X1999000200006

Rev. Bras. Frutic.

Furtado,Thais Destefani Ribeiro; Muniz,Joel Augusto; Silva,Edilson Marcelino; Fernandes,Jaqueline Gonçalves.

Abstract Jabuticaba tree is native to the Atlantic Forest in Southern Brazil, and its fruit is widely consumed in the fresh form, but it is highly perishable, requiring conservation techniques. The aim of this study was to describe the drying kinetics of jabuticaba pulp at temperatures of 50 and 60°C, comparing the Henderson, Simple Three-Parameter Exponential, Lewis, Thompson, Fick and Wang and Sing regression models and estimating the Absolute Drying Rate (ADR) for the best model. Parameters were estimated using the SAS software. The evaluation of the quality in the adjustment and selection of models was made based on the adjusted determination coefficient, Residual Standard Deviation and Akaike Information Criterion. Models presented good adjustment to...

EVOLUÇÃO DA PRODUÇÃO DE TOMATE DE MESA NO ESTADO DE RONDÔNIA

Palavras-chave: Food preservation; Moisture ratio; Nonlinear regression; Statistical models.

Ano: 2019

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452019000100903

AgEcon

Simao, Rogerio; Rodriguez, Tomas Daniel Menendez.

O tomate é uma das hortaliças mais consumidas no mundo todo, perdendo apenas para a batata. Este trabalho tem por objetivo mostrar a evolução da produção de tomate no Estado de Rondônia. A partir de dados fornecidos pelo IBGE – RO, EMATER – RO e SEAPES da produção de tomate em Rondônia de 1997 a 2006, foram calculadas as médias de crescimento da produção em quatro grandes regiões do Estado. Utilizando-se do método de regressão não linear, calculou-se as taxas de crescimento da área e produtividade bem como as contribuições da área cultivada e da produtividade para o aumento da produção no período de dez anos. Ao final do artigo verifica-se que tanto a área quanto a produtividade tiveram praticamente a mesma taxa percentual de contribuição para o aumento da...

Tipo: Conference Paper or Presentation

Palavras-chave: Tomate; Regressão não linear; Taxa de crescimento; Tomato; Nonlinear regression; Increase rate; Crop Production/Industries.

Ano: 2008

URL: http://purl.umn.edu/108154

Fitting nonlinear autoregressive models to describe coffee seed germination

Sousa,Iábita Fabiana; Kunzle Neto,Johan Eugen; Muniz,Joel Augusto; Guimarães,Renato Mendes; Savian,Taciana Villela; Muniz,Fabiana Rezende.

Cumulative germination of coffee has a longitudinal behavior mathematically characterized by a sigmoidal model. In the seed germination evaluation, the study of the germination curve may contribute to better understanding of this process. The aim of this study was to evaluate the goodness of fit of Logistic and Gompertz models, with independent and first-order autoregressive errors structure, AR (1), in the description of coffee (Coffea arabica L.) line Catuai vermelho IAC 99 germination, at five different potential germination. The data used were from an experiment conducted in 2011 at the Seed Analysis Laboratory of the Federal University of Lavras. The Logistic and Gompertz nonlinear models were appropriately adjusted to the percentage germination data....

Genomic growth curves of an outbred pig population

Palavras-chave: Growth models; Autocorrelated errors; Nonlinear regression; Germination potential; Regression and correlation.

Ano: 2014

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782014001102016

Genet. Mol. Biol.

Silva,Fabyano Fonseca e; Resende,Marcos Deon V. de; Rocha,Gilson Silvério; Duarte,Darlene Ana S.; Lopes,Paulo Sávio; Brustolini,Otávio J.B.; Thus,Sander; Viana,José Marcelo S.; Guimarães,Simone E.F..

In the current post-genomic era, the genetic basis of pig growth can be understood by assessing SNP marker effects and genomic breeding values (GEBV) based on estimates of these growth curve parameters as phenotypes. Although various statistical methods, such as random regression (RR-BLUP) and Bayesian LASSO (BL), have been applied to genomic selection (GS), none of these has yet been used in a growth curve approach. In this work, we compared the accuracies of RR-BLUP and BL using empirical weight-age data from an outbred F2 (Brazilian Piau X commercial) population. The phenotypes were determined by parameter estimates using a nonlinear logistic regression model and the halothane gene was considered as a marker for evaluating the assumptions of the GS...

Nonlinear quantile regression to describe the dry matter accumulation of garlic plants

Palavras-chave: Bayesian LASSO; Nonlinear regression; SNP effects.

Ano: 2013

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572013000400010

Puiatti,Guilherme Alves; Cecon,Paulo Roberto; Nascimento,Moysés; Nascimento,Ana Carolina Campana; Carneiro,Antônio Policarpo Souza; Silva,Fabyano Fonseca e; Puiatti,Mário; Cruz,Cosme Damião.

ABSTRACT: The objective of this study was to adjust nonlinear quantile regression models for the study of dry matter accumulation in garlic plants over time, and to compare them to models fitted by the ordinary least squares method. The total dry matter of nine garlic accessions belonging to the Vegetable Germplasm Bank of Universidade Federal de Viçosa (BGH/UFV) was measured in four stages (60, 90, 120 and 150 days after planting), and those values were used for the nonlinear regression models fitting. For each accession, there was an adjustment of one model of quantile regression (τ=0.5) and one based on the least squares method. The nonlinear regression model fitted was the Logistic. The Akaike Information Criterion was used to evaluate the goodness of...

Quantile regression of nonlinear models to describe different levels of dry matter accumulation in garlic plants

Palavras-chave: Quantile regression; Nonlinear regression; Allium sativum L.; Growth rate; Cluster analysis..

Ano: 2020

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782020000100203

Puiatti,Guilherme Alves; Cecon,Paulo Roberto; Nascimento,Moysés; Nascimento,Ana Carolina Campana; Carneiro,Antônio Policarpo Souza; Silva,Fabyano Fonseca e; Puiatti,Mário; Oliveira,Ana Carolina Ribeiro de.

ABSTRACT: Plant growth analyses are important because they generate information on the demand and necessary care for each development stage of a plant. Nonlinear regression models are appropriate for the description of curves of growth, since they include parameters with practical biological interpretation. However, these models present information in terms of the conditional mean, and they are subject to problems in the adjustment caused by possible outliers or asymmetry in the distribution of the data. Quantile regression can solve these problems, and it allows the estimation of different quantiles, generating more complete and robust results. The objective of this research was to adjust a nonlinear quantile regression model for the study of dry matter...

VARIATION IN MARGINAL RESPONSE TO NITROGEN FERTILIZER BETWEEN LOCATIONS

Palavras-chave: Quantile regression; Nonlinear regression; Dry matter; Allium sativum L.

Ano: 2018

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018000100203

AgEcon

Graybeal, Dale K..

A logistic growth equation with time and location varying parameters was used to model corn response to applied nitrogen. A nonlinear dummy-variable regression model provided a parsimonious representation of site and time effects on parameter values. The model was used to test for the equality of the mean marginal product of nitrogen fertilizer between locations on the coastal plain of North Carolina. Monte Carlo simulation and bootstrap simulation were used to construct finite sample covariance estimates. Results support rejection of the hypothesis that mean marginal products are equal when nitrogen is applied at 168 kg/ac. A comparison of bootstrapped errors and asymptotic errors suggests that results based on asymptotic theory are fairly reliable in...

Tipo: Journal Article

Palavras-chave: Bootstrap; Corn yield; Marginal product; Nitrogen fertilizer; Nonlinear regression; Crop Production/Industries; C200; C150; Q100.

Ano: 2000

URL: http://purl.umn.edu/15502

Water retention and penetration resistance equations for the least limiting water range

Leão,Tairone Paiva.

ABSTRACT: The least limiting water range is a soil physical quality indicator, which is useful to predict the optimum water range for plant growth in a given soil and to study the effects of soil use and management over this optimum water range by integrating the effects of available water, penetration resistance and air filled porosity. This study tested six equations to fit water retention and penetration resistance surface responses used to determine the least limiting water range and present a simple algorithm written in the open source software R for fitting, calculation and visualization of the least limiting water range. Five soils from Brazil and Canada, under different use and management conditions were used to test the functions. The results show...