Tiller size/population density compensation in grazed Coastcross bermudagrass swards
Autor(a) principal: | |
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Data de Publicação: | 2001 |
Outros Autores: | , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Scientia Agrícola (Online) |
Texto Completo: | https://www.revistas.usp.br/sa/article/view/21657 |
Resumo: | Several compensatory mechanisms in pastures do not allow optimisation of responses from the processes of herbage production and utilisation. Compensation due to tiller size/density relationships is one of these mechanisms. This experiment evaluated this process for Coastcross bermudagrass and compared the responses to those reported for temperate forages. Treatments were "steady state" sward surface heights of 5, 10, 15, and 20 cm that were maintained from August, 1998, through July, 1999 by sheep grazing. The experimental design was a randomised complete block, replicated four times. Pasture responses were evaluated on four separate dates (15/12/1998, 25/01/1999, 07/04/1999 and 04/07/1999) with respect to: tiller population density, tiller weight, leaf mass and leaf area per tiller and herbage mass (biomass). Tiller volume, leaf area index (LAI), tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were calculated. Simple regression analyses between tiller population density and tiller weight were also performed. Coastcross swards showed a tiller size/density compensation mechanism where high tiller population densities were associated with small tillers and vice-versa; except on the last evaluation. However, regression analysis revealed linear coefficients of -3.83 to -2.05, which are lower than the theoretical expectation of -3/2. The lower R values observed, when compared to those reported for perennial ryegrass, suggest that Coastcross swards optimised their LAI via clonal integration among tillers in contrast with tillers of cool-season grasses that respond more as individuals. However, this hypothesis has yet to be experimentally verified. |
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Tiller size/population density compensation in grazed Coastcross bermudagrass swards Compensação tamanho/densidade populacional de perfilhos em pastagens de capim Coastcross CynodonLAItillermorphologyCynodonIAFperfilhomorfologia Several compensatory mechanisms in pastures do not allow optimisation of responses from the processes of herbage production and utilisation. Compensation due to tiller size/density relationships is one of these mechanisms. This experiment evaluated this process for Coastcross bermudagrass and compared the responses to those reported for temperate forages. Treatments were "steady state" sward surface heights of 5, 10, 15, and 20 cm that were maintained from August, 1998, through July, 1999 by sheep grazing. The experimental design was a randomised complete block, replicated four times. Pasture responses were evaluated on four separate dates (15/12/1998, 25/01/1999, 07/04/1999 and 04/07/1999) with respect to: tiller population density, tiller weight, leaf mass and leaf area per tiller and herbage mass (biomass). Tiller volume, leaf area index (LAI), tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were calculated. Simple regression analyses between tiller population density and tiller weight were also performed. Coastcross swards showed a tiller size/density compensation mechanism where high tiller population densities were associated with small tillers and vice-versa; except on the last evaluation. However, regression analysis revealed linear coefficients of -3.83 to -2.05, which are lower than the theoretical expectation of -3/2. The lower R values observed, when compared to those reported for perennial ryegrass, suggest that Coastcross swards optimised their LAI via clonal integration among tillers in contrast with tillers of cool-season grasses that respond more as individuals. However, this hypothesis has yet to be experimentally verified. Vários mecanismos compensatórios em pastagens não permitem a otimização de respostas dos processos determinantes da produção e da utilização de forragem. O mecanismo de compensação tamanho/densidade é um desses mecanismos. Este experimento avaliou esse processo originalmente descrito para plantas forrageiras de clima temperado. Os tratamentos corresponderam às alturas de pasto de 5, 10, 15 e 20 cm mantidas em steady state por ovinos em lotação contínua de Agosto de 1998 a Julho de 1999. O delineamento experimental utilizado foi o de blocos completos ao acaso, com quatro repetições. As respostas avaliadas foram: densidade populacional de perfilhos, massa por perfilho, massa de folhas e área foliar por perfilho e biomassa total. Cálculos de volume por perfilho, índice de área foliar (IAF), relação folha:haste por perfilho e área foliar:volume do perfilho (R) foram executados. Análises de regressão simples entre densidade populacional de perfilhos e peso por perfilho foram também realizadas. As avaliações foram realizadas em dezembro/98, janeiro, abril e julho/99. Pastos de Coastcross apresentaram um mecanismo de compensação tamanho/densidade onde altas densidades populacionais estiveram associadas com perfilhos pequenos e vice-versa, exceto na última avaliação. Contudo, a análise de regressão revelou inclinações de reta que variaram de -3,83 a -2,05, superiores à expectativa teórica de -3/2. Em dezembro e janeiro os aumentos em biomassa foram resultado de aumentos em massa por perfilho. Os baixos valores de R observados, quando comparados àqueles determinados para azevém perene, sugerem que pastos de Coastcross otimizem seu IAF via integração clonal entre perfilhos, diferentemente de azevém que operaria através de perfilhos individuais. No entanto, esta hipótese necessita ser comprovada experimentalmente. Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz2001-12-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://www.revistas.usp.br/sa/article/view/2165710.1590/S0103-90162001000400002Scientia Agricola; v. 58 n. 4 (2001); 655-665Scientia Agricola; Vol. 58 No. 4 (2001); 655-665Scientia Agricola; Vol. 58 Núm. 4 (2001); 655-6651678-992X0103-9016reponame:Scientia Agrícola (Online)instname:Universidade de São Paulo (USP)instacron:USPenghttps://www.revistas.usp.br/sa/article/view/21657/23681Copyright (c) 2015 Scientia Agricolainfo:eu-repo/semantics/openAccessSbrissia, André FischerSilva, Sila Carneiro daCarvalho, Carlos Augusto Brandão deCarnevalli, Roberta AparecidaPinto, Luiz Felipe de MouraFagundes, Jaílson LaraPedreira, Carlos Guilherme Silveira2015-07-07T11:37:39Zoai:revistas.usp.br:article/21657Revistahttp://revistas.usp.br/sa/indexPUBhttps://old.scielo.br/oai/scielo-oai.phpscientia@usp.br||alleoni@usp.br1678-992X0103-9016opendoar:2015-07-07T11:37:39Scientia Agrícola (Online) - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards Compensação tamanho/densidade populacional de perfilhos em pastagens de capim Coastcross |
title |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards |
spellingShingle |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards Sbrissia, André Fischer Cynodon LAI tiller morphology Cynodon IAF perfilho morfologia |
title_short |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards |
title_full |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards |
title_fullStr |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards |
title_full_unstemmed |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards |
title_sort |
Tiller size/population density compensation in grazed Coastcross bermudagrass swards |
author |
Sbrissia, André Fischer |
author_facet |
Sbrissia, André Fischer Silva, Sila Carneiro da Carvalho, Carlos Augusto Brandão de Carnevalli, Roberta Aparecida Pinto, Luiz Felipe de Moura Fagundes, Jaílson Lara Pedreira, Carlos Guilherme Silveira |
author_role |
author |
author2 |
Silva, Sila Carneiro da Carvalho, Carlos Augusto Brandão de Carnevalli, Roberta Aparecida Pinto, Luiz Felipe de Moura Fagundes, Jaílson Lara Pedreira, Carlos Guilherme Silveira |
author2_role |
author author author author author author |
dc.contributor.author.fl_str_mv |
Sbrissia, André Fischer Silva, Sila Carneiro da Carvalho, Carlos Augusto Brandão de Carnevalli, Roberta Aparecida Pinto, Luiz Felipe de Moura Fagundes, Jaílson Lara Pedreira, Carlos Guilherme Silveira |
dc.subject.por.fl_str_mv |
Cynodon LAI tiller morphology Cynodon IAF perfilho morfologia |
topic |
Cynodon LAI tiller morphology Cynodon IAF perfilho morfologia |
description |
Several compensatory mechanisms in pastures do not allow optimisation of responses from the processes of herbage production and utilisation. Compensation due to tiller size/density relationships is one of these mechanisms. This experiment evaluated this process for Coastcross bermudagrass and compared the responses to those reported for temperate forages. Treatments were "steady state" sward surface heights of 5, 10, 15, and 20 cm that were maintained from August, 1998, through July, 1999 by sheep grazing. The experimental design was a randomised complete block, replicated four times. Pasture responses were evaluated on four separate dates (15/12/1998, 25/01/1999, 07/04/1999 and 04/07/1999) with respect to: tiller population density, tiller weight, leaf mass and leaf area per tiller and herbage mass (biomass). Tiller volume, leaf area index (LAI), tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were calculated. Simple regression analyses between tiller population density and tiller weight were also performed. Coastcross swards showed a tiller size/density compensation mechanism where high tiller population densities were associated with small tillers and vice-versa; except on the last evaluation. However, regression analysis revealed linear coefficients of -3.83 to -2.05, which are lower than the theoretical expectation of -3/2. The lower R values observed, when compared to those reported for perennial ryegrass, suggest that Coastcross swards optimised their LAI via clonal integration among tillers in contrast with tillers of cool-season grasses that respond more as individuals. However, this hypothesis has yet to be experimentally verified. |
publishDate |
2001 |
dc.date.none.fl_str_mv |
2001-12-01 |
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/21657 10.1590/S0103-90162001000400002 |
url |
https://www.revistas.usp.br/sa/article/view/21657 |
identifier_str_mv |
10.1590/S0103-90162001000400002 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
https://www.revistas.usp.br/sa/article/view/21657/23681 |
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. 58 n. 4 (2001); 655-665 Scientia Agricola; Vol. 58 No. 4 (2001); 655-665 Scientia Agricola; Vol. 58 Núm. 4 (2001); 655-665 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_ |
1787713252640161792 |