Evaluation of a pasture production model using empirical tests

ARROQUY, J; NASCA, J; FELDKAMP, C. R.; BERONE, G; COLOMBATTO, D

RIA

Instituto Nacional de Tecnología Agropecuaria

Año: 2020 vol. 46 p. 88 - 95

0325-8718

For this work, a pasture growth model developed by McCall and Bishop-Hurley, was used. The objective was to evaluate the model, using empirical tests. A tropical pasture named Chloris gayana, was used. For the empirical evaluation a database from the Animal Research Institute of Semiarid Chaco (INTA), was used, including information of herbage accumulated during the growing season, and cutting trials based on the difference between pre- and post-grazing herbage. The statistics calculated were root mean square error, relative root mean square error, mean error and Theil coefficients. The Theil coefficients for accumulated herbage (Um = 0.35, Us = 0.1, Uc= 0.64) and cutting trials (Um = 0.08, Us = 0.08, Uc = 0, 84), showed that the model did not present systematic errors. The growth pattern of simulated herbage was 7% Oct-Nov, 64% Dec-Jan-Feb, 29% Mar-Apr-May. The work shows the potential of the pasture model to simulate the forage production of Chloris gayana in subtropical environments, capturing variations in the environment. In this sense, it can be useful for studying interactions between management strategies and dynamics responses of pastures in highly variable climates.