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| Registros recuperados: 127 | |
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| Jarquín-Sánchez,Aarón; Salgado-García,Sergio; Palma-López,David J; Camacho-Chiu,Wilder. |
| The objective of this study was to predict the concentration of soil organic matter (SOM) in tropical soils using near-infrared spectroscopy (NIRS) for samples measured within a polyethylene bag and without a bag. One hundred and fifty six soil samples from the humid tropics of Tabasco, Mexico with contrasting chemical characteristics were selected. The samples were dried, ground, and sieved through 2 mm and 5 mm screens, and their SOM contents were determined using the Walkley-Black method. The soil samples were packed in polyethylene bags, and SOM was measured directly with and without a bag using a quartz probe (FOSS 5000 model of NIRsystems, DK-3400 Hillerod,Denmark) for a range from 1100 to 2000 nm to obtain a prediction model of SOM. The model for... |
| Tipo: Journal article |
Palavras-chave: Chemical analysis; Tropical soil; Optical fiber; Model; Organic matter prediction. |
| Ano: 2012 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202012000200015 |
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| Cerdeira,Antonio Luiz; Paraíba,Lourival Costa; Queiroz,Sonia Claudia Nascimento de; Matallo,Marcus Barifouse; Franco,Daniel Andrade de siqueira; Ferracini,Vera Lúcia. |
| Sugarcane is an important crop for sugar and biofuel production in Brazil. Growers depend greatly on herbicides to produce it. This experiment used herbicide physical-chemical and sugarcane plant physiological properties to simulate herbicide uptake and estimate the bioconcentration factor (BCF). The (BCF) was calculated for the steady state chemical equilibrium between the plant herbicide concentration and soil solution. Plant-water partition coefficient (sugarcane bagasse-water partition coefficient), herbicide dilution rate, metabolism and dissipation in the soil-plant system, as well as total plant biomass factors were used. In addition, we added Tebuthiuron at rate of 5.0kg a.i. ha-1 to physically test the model. In conclusion, the model showed the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbicide; Bioconcentration factor; Plant uptake; Model; Bagasse adsorption. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000400591 |
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| Maria,Luciano de Souza; Litter,Felipe Adolfo; Carneiro,Márcia de Almeida; Silva,Fabrícia Rodrigues da; Garcia,Marcos Leandro; Carvalho,Marco Antonio Camillo de. |
| ABSTRACT: Production of Tectona grandis (teak) in integrated systems with livestock or agriculture demonstrates high potential of financial return. However, studies on the development of teak are still scarce, especially in the northern region state of Mato Grosso. In this study we sought to evaluate dendometric variables of a clonal population of teak in a forest-livestock integration system (LFIS), during a period of 53 months in the city of Alta Floresta, Mato Grosso, Brazil. For this purpose, three installments were samples, a total of 360 individuals, and for each the diameter was measured at 1.3 meters from the base so as to calculate the total volume, the current annual increment (CAI) and mean annual increment (MAI), and five adjusted regression... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Growth; Model; LFIS; Teak. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000900301 |
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| Streck,Nereu Augusto. |
| Temperature is a major factor that affects metabolic processes in living organisms. Thermal time has been widely used to account for the effects of temperature on crop growth and development. However, the thermal time approach has been criticized because it assumes a linear relationship between the rate of crop growth or development and temperature. The response of the rate of crop growth and development to temperature is nonlinear. The objective of this study was to develop a generalized nonlinear temperature response function for some growth and developmental parameters in kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson). The nonlinear function has three coefficients (the cardinal temperatures), which were 0ºC, 25ºC, and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Temperature; Model; Growth; Development; Kiwifruit. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782003000200012 |
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| Streck,Nereu Augusto. |
| Developmental models can help growers to decide management practices, and to predict flowering and harvest time. Currently, a double exponential function is proposed as a generalized temperature response function for chrysanthemum. This function is not the most appropriate because its parameters lack biological meaning. The objective of this study was to develop a nonlinear temperature response function of chrysanthemum development that has parameters with biological meaning. The proposed function is a beta function with three parameters, the cardinal temperatures (minimum, optimum, and maximum temperatures for development), which were defined as 0, 22, and 35ºC. Published data of temperature response of development of three cultivars, which are... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Phenology; Flowering; Model. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782004000100008 |
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| Langner,Josana Andreia; Streck,Nereu Augusto; Durigon,Angelica; Silva,Stefanía Dalmolin da; Lago,Isabel; Dalmago,Genei Antonio; Reiniger,Lia Rejane Silveira; Scheffel,Lúcio Gabriel; Poersch,Anderson Haas. |
| ABSTRACT: The objective of this study was to compare the simulations of leaf appearance of landrace and improved maize cultivars using the CSM-CERES-Maize (linear) and the Wang and Engel models (nonlinear). The coefficients of the models were calibrated using a data set of total leaf number collected in the 11/04/2013 sowing date for the landrace varieties ‘Cinquentinha’ and ‘Bico de Ouro’ and the simple hybrid ‘AS 1573PRO’. For the ‘BRS Planalto’ variety, model coefficients were estimated with data from 12/13/2014 sowing date. Evaluation of the models was with independent data sets collected during the growing seasons of 2013/2014 (Experiment 1) and 2014/2015 (Experiment 2) in Santa Maria, RS, Brazil. Total number of leaves for both landrace and improved... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays L.; Vegetative development; Air temperature; Sowing time; Model. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018000100201 |
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| Streck,Nereu Augusto. |
| Response functions used in crop simulation models are usually different for different physiological processes and cultivars, resulting in many unknown coefficients in the response functions. This is the case of African violet (Saintpaulia ionantha Wendl.), where a generalized temperature response for leaf growth and development has not been developed yet. The objective of this study was to develop a generalized nonlinear temperature response function for leaf appearance rate and leaf elongation rate in African violet. The nonlinear function has three coefficients, which are the cardinal temperatures (minimum, optimum, and maximum temperatures). These coefficients were defined as 10, 24, and 33ºC, based on the cardinal temperatures of other tropical... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Temperature; Model; Leaf growth; Leaf development; African violet. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782004000100009 |
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| Registros recuperados: 127 | |
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