Resumo

OJEDA, J.J.; QUINODOZ, J.E.  e  LEZANA, Lucrecia. Estimación de disponibilidad forrajera de pasturas base alfalfa y verdeos invernales en el sudoeste de Entre Ríos. RIA. Rev. investig. agropecu. [online]. 2021, vol.47, n.1, pp.26-45.  Epub 09-Jun-2021. ISSN 1669-2314.

Forage availability is the most important variable for estimating livestock stock rates in alfalfa-based perennial pastures (PP) and forage winter crops (VI) in the southwest of Entre Rios, Argentina. Despite its importance, there is little information about methods for estimating forage availability under these environments. The objective of this paper was to calibrate and validate mathematical models that allow to estimate forage availability (i.e. accumulated aerial biomass [BA] in a period) from the height of compressed forage (AFC). In general, the estimation of BA on annual (R2.=0.68 and R2.=0.78, PP and VV respectively) and seasonal basis (R2.=0.67-0.74 and R.=0.71-0.83 PP and VV, respectively) was satisfactory (calibration). Likewise, the model’s accuracy was satisfactory when they were tested with an independent dataset (validation, CCC [concordance correlation coefficient]=0.68-0.77). The BA/AFC ratio was greater for the forage stratum >=10 cm. The spatial arrangement of the species generated a lower density of forage in the forage stratum <10 cm between PP and VI. These models could be used to estimate BA in the range of forage height of 5-30 cm, compatible with the usual grazing thresholds in the southwest of Entre Rios.

Palavras-chave : rising plate meter; mixed pastures; ryegrass; oats; mathematical models.

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