Resumo

LOPEZ-GUERRERO, Isaías; FONTENOT, Joseph P.  e  GARCIA-PENICHE, Teresa Beatriz. Comparison of four biomass estimation methods in Tall Fescue pastures. Rev. mex. de cienc. pecuarias [online]. 2011, vol.2, n.2, pp.209-220. ISSN 2448-6698.

In grazing experiments, forage mass is a necessary measurement for estimating other grassland attributes such as growth, utilization, and decomposition. The predicament is that forage biomass cannot be measured in large scale grazing trials; it can only be estimated through some sampling technique. When subsampling, the herbage cutting method (HCM) has been accepted as the most reliable, provided an adequate number of samples are taken. There are, however, some indirect methods that may be easier, less expensive, and faster than clipping. For that reason, the purpose of the present study was to compare HCM with three indirect methods for estimating the forage mass: pasture capacitance meter (PCM), pasture plate meter (PPM) and visual estimation (VE). The experiment was carried out on six tall fescue paddocks during the 2002 and 2003 growing seasons. Calibration equations were put together for each indirect method for every sampling date using the simple linear regression technique. Coefficients of determination, for the pooled calibration equations, were 0.686, 0.751, and 0.862 for PCM, PMP, and VE, respectively. Significant differences (P<0.01) were found due to sampling method, date, and their interaction. Contrasts showed that forage mass obtained by HCM was overestimated (P<0.01) by the three indirect methods.

Palavras-chave : Tall Fescue; Biomass; Pasture plate meter; Visual estimation; Capacitance.

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