Tiller size/density compensation in grazed Tifton 85 bermudagrass swards

Pesquisa Agropecuária Brasileira

André Fischer Sbrissia¹  Sila Carneiro Da Silva¹  Cory Matthew²  Carlos Augusto Brandão De Carvalho¹  Roberta Aparecida Carnevalli¹  Luiz Felipe De Moura Pinto¹  Jaílson Lara Fagundes¹  Carlos Guilherme Silveira Pedreira¹ 

[1] ,Escola Superior de Agricultura Luiz de Queiróz Departamento de Zootecnia Piracicaba SP

关键词: Cynodon;    leaf area index;    mass;    density;    plant morphology;    Cynodon;    índice de superfície foliar;    massa;    densidade;    morfologia vegetal;   

DOI  :  10.1590/S0100-204X2003001200013

来源: SciELO

【 摘 要 】

The objective of this study was to evaluate the occurrence of the tiller size/density compensation mechanism in Tifton 85 bermudagrass swards grazed by sheep under continuous stocking. Treatments corresponded to four sward steady state conditions (5, 10, 15, and 20 cm of sward surface height), maintained by sheep grazing. The experimental design was a complete randomized block with four replicates. Pasture responses evaluated include: tiller population density, tiller mass, leaf mass and leaf area per tiller, and herbage mass. Tiller volume, leaf area index, tiller leaf/stem ratio, and tiller leaf area/volume ratio were calculated and simple regression analyses between tiller population density and tiller mass were performed. Measurements were made in December, 1998, and January, April, and July, 1999. The swards showed a tiller size/density compensation mechanism in which high tiller population densities were associated with small tillers and vice-versa, except in July, 1999. Regression analyses revealed that linear coefficients were steeper than the theoretical expectation of -3/2. Increments in herbage mass were attributable to increases in tiller mass in December and January. Leaf area/volume ratio values of Tifton 85 tillers were much lower than those commonly found for temperate grass species.

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