Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil
Autor(a) principal: | |
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Data de Publicação: | 1994 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Scientia Agrícola (Online) |
Texto Completo: | https://www.revistas.usp.br/sa/article/view/20195 |
Resumo: | Soil water balance components were measured during two periods (from 1989 to 1991) on a Dark Red Latosol (oxisol) in Piracicaba,SP, Brazil. The change in soil water storage and the soil water fluxes at the lower limit of the rooting zone were calculated for a transect of 25 observation plots. Hydraulic head gradients were determined by tensiometer measurements. Soil water flux densities were estimated through Darcy's equation. The actual evapotranspiration of the crops and weeds and the actual evaporation of bare soil were obtained from the water balance equation and this for two periods under different crop rotations. For the first period the sequence was bare soil-corn-weeds and for the second period it was stubble mulch-weeds-corn. For assessing the crop coefficients the potential evapotranspiration was calculated according to two different methods. The first method was based on the modified Penman equation with grass as a reference crop, to obtain this way reference coefficients, and the second method was based on the pan "A" evaporation data in order to obtain pan coefficients. These coefficients were compared with the tabulated crop coefficients. In general when there was no shortage of water during the corn growth, the crop coefficients k c"A" and k c ref were very close to the k c values. |
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Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil Determinação de coeficientes de cultura para o milho durante um experimento de evapotranspiração em um oxisol do Brasil coeficiente de culturaevapotranspiraçãovariabilidade espacialcrop coefficientevapotranspirationspatial variability Soil water balance components were measured during two periods (from 1989 to 1991) on a Dark Red Latosol (oxisol) in Piracicaba,SP, Brazil. The change in soil water storage and the soil water fluxes at the lower limit of the rooting zone were calculated for a transect of 25 observation plots. Hydraulic head gradients were determined by tensiometer measurements. Soil water flux densities were estimated through Darcy's equation. The actual evapotranspiration of the crops and weeds and the actual evaporation of bare soil were obtained from the water balance equation and this for two periods under different crop rotations. For the first period the sequence was bare soil-corn-weeds and for the second period it was stubble mulch-weeds-corn. For assessing the crop coefficients the potential evapotranspiration was calculated according to two different methods. The first method was based on the modified Penman equation with grass as a reference crop, to obtain this way reference coefficients, and the second method was based on the pan "A" evaporation data in order to obtain pan coefficients. These coefficients were compared with the tabulated crop coefficients. In general when there was no shortage of water during the corn growth, the crop coefficients k c"A" and k c ref were very close to the k c values. Os componentes do balanço hídrico foram medidos durante dois períodos (de 1989 a 1991) em terra roxa estruturada, em Piracicaba,SP, Brasil. As variações de armazenamento de água e os fluxos de água no solo no limite inferior da zona radicular foram calculados para uma transeção de 25 parcelas experimentais. Gradientes hidráulicos foram determinados por meio de medidas tensiométricas. Densidades de fluxo de água foram estimadas através da equação de Darcy. A evapotranspiração atual das culturas e das ervas daninhas e a evaporação atual do solo nú foram obtidas da equação do balanço hídrico, para dois períodos, sob diferentes rotações de cultura. Para o primeiro período a seqüência foi solo nú - milho - ervas daninhas e para o segundo cobertura morta - ervas daninhas - milho. Para determinar os coeficientes de cultura, a evapotranspiração potencial foi calculada por dois métodos. O primeiro foi baseado na equação de Penman modificada, com a grama como cobertura de referência, obtendo assim os coeficientes de referência, e o segundo baseado no tanque de evaporação tipo classe "A", obtendo os coeficientes de tanque. Estes coeficientes foram comparados com os coeficientes de cultura tabulados. De uma forma geral, em períodos sem falta de água para a cultura, os coeficientes de referência e de tanque se assemelharam bastante aos coeficientes de cultura. Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz1994-08-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://www.revistas.usp.br/sa/article/view/2019510.1590/S0103-90161994000200012Scientia Agricola; v. 51 n. 2 (1994); 270-278Scientia Agricola; Vol. 51 No. 2 (1994); 270-278Scientia Agricola; Vol. 51 Núm. 2 (1994); 270-2781678-992X0103-9016reponame:Scientia Agrícola (Online)instname:Universidade de São Paulo (USP)instacron:USPenghttps://www.revistas.usp.br/sa/article/view/20195/22312Copyright (c) 2015 Scientia Agricolainfo:eu-repo/semantics/openAccessVillagra, M.M.Gabriels, D.Verplancke, H.Hartmann, R.Reichardt, K.2015-07-07T11:18:22Zoai:revistas.usp.br:article/20195Revistahttp://revistas.usp.br/sa/indexPUBhttps://old.scielo.br/oai/scielo-oai.phpscientia@usp.br||alleoni@usp.br1678-992X0103-9016opendoar:2015-07-07T11:18:22Scientia Agrícola (Online) - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil Determinação de coeficientes de cultura para o milho durante um experimento de evapotranspiração em um oxisol do Brasil |
title |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil |
spellingShingle |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil Villagra, M.M. coeficiente de cultura evapotranspiração variabilidade espacial crop coefficient evapotranspiration spatial variability |
title_short |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil |
title_full |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil |
title_fullStr |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil |
title_full_unstemmed |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil |
title_sort |
Estimating crop coefficients for corn during an evapotranspiration experiment on an oxisol in Brazil |
author |
Villagra, M.M. |
author_facet |
Villagra, M.M. Gabriels, D. Verplancke, H. Hartmann, R. Reichardt, K. |
author_role |
author |
author2 |
Gabriels, D. Verplancke, H. Hartmann, R. Reichardt, K. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Villagra, M.M. Gabriels, D. Verplancke, H. Hartmann, R. Reichardt, K. |
dc.subject.por.fl_str_mv |
coeficiente de cultura evapotranspiração variabilidade espacial crop coefficient evapotranspiration spatial variability |
topic |
coeficiente de cultura evapotranspiração variabilidade espacial crop coefficient evapotranspiration spatial variability |
description |
Soil water balance components were measured during two periods (from 1989 to 1991) on a Dark Red Latosol (oxisol) in Piracicaba,SP, Brazil. The change in soil water storage and the soil water fluxes at the lower limit of the rooting zone were calculated for a transect of 25 observation plots. Hydraulic head gradients were determined by tensiometer measurements. Soil water flux densities were estimated through Darcy's equation. The actual evapotranspiration of the crops and weeds and the actual evaporation of bare soil were obtained from the water balance equation and this for two periods under different crop rotations. For the first period the sequence was bare soil-corn-weeds and for the second period it was stubble mulch-weeds-corn. For assessing the crop coefficients the potential evapotranspiration was calculated according to two different methods. The first method was based on the modified Penman equation with grass as a reference crop, to obtain this way reference coefficients, and the second method was based on the pan "A" evaporation data in order to obtain pan coefficients. These coefficients were compared with the tabulated crop coefficients. In general when there was no shortage of water during the corn growth, the crop coefficients k c"A" and k c ref were very close to the k c values. |
publishDate |
1994 |
dc.date.none.fl_str_mv |
1994-08-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.revistas.usp.br/sa/article/view/20195 10.1590/S0103-90161994000200012 |
url |
https://www.revistas.usp.br/sa/article/view/20195 |
identifier_str_mv |
10.1590/S0103-90161994000200012 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
https://www.revistas.usp.br/sa/article/view/20195/22312 |
dc.rights.driver.fl_str_mv |
Copyright (c) 2015 Scientia Agricola info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Copyright (c) 2015 Scientia Agricola |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz |
publisher.none.fl_str_mv |
Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz |
dc.source.none.fl_str_mv |
Scientia Agricola; v. 51 n. 2 (1994); 270-278 Scientia Agricola; Vol. 51 No. 2 (1994); 270-278 Scientia Agricola; Vol. 51 Núm. 2 (1994); 270-278 1678-992X 0103-9016 reponame:Scientia Agrícola (Online) instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Scientia Agrícola (Online) |
collection |
Scientia Agrícola (Online) |
repository.name.fl_str_mv |
Scientia Agrícola (Online) - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
scientia@usp.br||alleoni@usp.br |
_version_ |
1787713251517136896 |