Validation of the Botanal method in a Phalaris aquatica and Trifolium subterraneum pasture. IV. Time required and precisipn in the estimation of dry matter availability and botanical composition

Mario Silva G.1, Fernando Squella N.2, Alberto Mansilla M.1 y Carolina Márquez G.3

The present study had the objective to evaluate the time required and the precision of the cutting and the comparative yield methods to estimate dry matter availability, and of the hand separation and weight rank methods, to estimate botanical composition, in a Phalaris aquatica (hardínggrass) and Trifolium subterraneum (subclover) pasture. This research was conducted at the Hidango Field Station (INIA) (34º07' S lat., and 71º44' W long), from July 1983 to February 1984, in pastures grazed by cattle or sheep or deferred for hay. The coefficient of variation was used to analyze the precision and the time required. Results indicated that increasing the number of samples from 5 to 10 strongly increased precision. In general, the comparative yield method was better than the cutting method in the estimation of dry matter availability. Botanical composition was satisfactorily estimated by the dry weight rank method; but under many situations, the hand separation method seems to be superior.

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1 Facultad de Ciencias Agrarias y Forestales, Universidad de Chile, Casilla 1004, Santiago, Chile,
2 Estación Experimental La Platina (INlA), Casilla 439, Correo 3, Santiago, Chile,
3 Pericles 1213, Depto, 203, Santiago, Chile,

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