02021naa a2200229 a 450000100080000000500110000800800410001902400490006010000180010924501010012726000090022830000140023752013520025165300260160365300210162970000180165070000180166870000240168670000230171070000160173377300420174919421842024-10-14       2013    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.2134/agronj2012.02452DOI1 aARAUJO, L. C.  aSimulating Guinea Grass productionbempirical and mechanistic approaches.h[electronic resource]  c2013  ap. 61-69.  aTropical grasses are economically important for cattle production in Brazil and accurate simulation models for tropical pastures can benefit forage researchers and farm managers improve tropical forage production systems. This research calibrated and validated four modeling approaches of contrasting complexity to simulate mass production of Guineagrass (Panicum maximum Jacq. cv. ?Mombaça?). The models included three empirical agro-climatic models [i.e. a cumulative degree-day (DDi), a photo-thermal-units (PUi), and a climatic growth index (CGIi)]; and a bio-physical simulation model i.e. APSIM-Growth. Data sets for calibration and independent validation included records of frequent above-ground dry matter production over the 2005-2006 and 2010-2011 growing seasons from three trials. All models performed well during calibration (R2 = 0.78 - 0.86; and coefficient of variation = 26 - 32.1%). During model validation the R2 varied between 0.69 and 0.78; the agreement index was between 0.88 and 0.93; the coefficient of variation between 37.6 and 50.2%; and the mean bias error between 6 and 470 kg ha-1. Even though all models were in agreement between simulated and observed results, APSIM-Growth was able to simulate Guineagrass production across a broader climate range, soils and management (i.e. nitrogen fertilization) conditions.  aGuinegrass production  aTropical pasture1 aSANTOS, P. M.1 aRODRIGUEZ, D.1 aPEZZOPANE, J. R. M.1 aOLIVEIRA, P. P. A.1 aCRUZ, P. G.  tAgronomy Journalgv. 105, n. 1, 2013.