Tiller size/population density compensation in grazed Coastcross bermudagrass swards

Scientia Agricola

André Fischer Sbrissia²  Sila Carneiro Da Silva¹  Carlos Augusto Brandão De Carvalho²  Roberta Aparecida Carnevalli²  Luiz Felipe De Moura Pinto²  Jaílson Lara Fagundes²  Carlos Guilherme Silveira Pedreira¹ 

[1] ,Unversidade de São Paulo Escola Superior de Agricultura Luiz de Queiroz

关键词: Cynodon;    LAI;    tiller;    morphology;    Cynodon;    IAF;    perfilho;    morfologia;   

DOI  :  10.1590/S0103-90162001000400002

来源: SciELO

【 摘 要 】

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.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License