Biomass components of Pennisetum purpureum cv. Roxo managed at different growth ages and seasons

Theyson Duarte Maranhão,Francisco Gleyson Da Silveira Alves,Marcos Neves Lopes,Roberto Cláudio Fernandes Franco Pompeu,Maria Socorro De Souza Carneiro,Rafael Rodrigues Da Silva,Magno José Duarte Cândido,Rafael Nogueira Furtado

doi:10.1590/s1519-99402018000100002

Theyson Duarte Maranhão, Francisco Gleyson Da Silveira Alves + Show 6 more

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https://doi.org/10.1590/s1519-99402018000100002

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Abstract

SUMMARY This study was carried out aiming to evaluate the biomass components of elephant grass cv. Roxo at seven growth ages, during rainy, transition and dry seasons. A completely randomized design was adopted with a split plot arrangement over time. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54 and 63) and three seasons (rainy, transition and dry). The variables green forage biomass, dead forage biomass, green stem biomass and green leaf blade biomass showed positive linear responses to age and had their magnitude influenced by the evaluated seasons. The live/dead material ratio showed a decreasing linear response as a function of age. The leaf blade/stem ratio showed a negative linear adjustment in the rainy season, reaching a critical value of 1.0 at 59 days, and it showed a quadratic adjustment in the transition season, with the maximum point at 27.53 days; however, this ratio was not influenced by age in the dry season, revealing an average value of 2.22 ± 0.27. The canopy height and leaf area index showed a positive linear response to age in the three seasons. Tiller population density showed quadratic behaviour for age, with maximum estimated values of 134 and 110 til. m-2 at 31.24 and 37.40 days in the rainy and dry seasons, respectively. Rainfall seasonality influences the magnitude of the daily increase of the distinct biomass components of Pennisetum purpureum cv. Roxo.

Highlights

Elephant grass (Pennisetum purpureum) is widespread in tropical and subtropical regions, and it can be managed under grazing or cutting, due to its good agronomic characteristics, such as adaptation to different soil and climatic conditions, high productivity, perenniality, and responsiveness to management
The morphophysiological characteristics are conditioned by the abiotic factors to which the canopy is submitted, since, the expression of morphogenic characteristics is genetically determined, its magnitude is influenced by extrinsic factors, and morphogenesis is the determining event for the canopy structure
This study aimed to evaluate the biomass components of elephant grass cv

Summary

Introduction

Elephant grass (Pennisetum purpureum) is widespread in tropical and subtropical regions, and it can be managed under grazing or cutting, due to its good agronomic characteristics, such as adaptation to different soil and climatic conditions, high productivity, perenniality, and responsiveness to management. The variability of rainfall is the most inductive abiotic factor of phenotypic plasticity of forage plants managed under waterless conditions. Biomass production is another variable strongly influenced by climatic changes. Alencar et al (2009), working with six grasses of different genera, verified effects of the seasonality on the variable total forage biomass Biomass production is another variable strongly influenced by climatic changes. Alencar et al (2009), working with six grasses of different genera, verified effects of the seasonality on the variable total forage biomass

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