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Simulating pasture growth rates in Australian and New Zealand grazing systems


Cullen, BR and Eckard, RJ and Callow, MN and Johnson, IR and Chapman, DF and Rawnsley, RP and Garcia, SC and White, T and Snow, VO, Simulating pasture growth rates in Australian and New Zealand grazing systems, Australian Journal of Agricultural Research, 59, (8) pp. 761-768. ISSN 0004-9409 (2008) [Refereed Article]

DOI: doi:10.1071/AR7371


DairyMod, EcoMod, and the SGS Pasture Model are mechanistic biophysical models developed to explore scenarios in grazing systems. The aim of this manuscript was to test the ability of the models to simulate net herbage accumulation rates of ryegrass-based pastures across a range of environments and pasture management systems in Australia and New Zealand. Measured monthly net herbage accumulation rate and accumulated yield data were collated from ten grazing system experiments at eight sites ranging from cool temperate to subtropical environments. The local climate, soil, pasture species, and management (N fertiliser, irrigation, and grazing or cutting pattern) were described in the model for each site, and net herbage accumulation rates modelled. The model adequately simulated the monthly net herbage accumulation rates across the range of environments, based on the summary statistics and observed patterns of seasonal growth, particularly when the variability in measured herbage accumulation rates was taken into account. Agreement between modelled and observed growth rates was more accurate and precise in temperate than in subtropical environments, and in winter and summer than in autumn and spring. Similarly, agreement between predicted and observed accumulated yields was more accurate than monthly net herbage accumulation. Different temperature parameters were used to describe the growth of perennial ryegrass cultivars and annual ryegrass; these differences were in line with observed growth patterns and breeding objectives. Results are discussed in the context of the difficulties in measuring pasture growth rates and model limitations. © CSIRO 2008.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Crop and pasture production
Research Field:Crop and pasture production not elsewhere classified
Objective Division:Animal Production and Animal Primary Products
Objective Group:Pasture, browse and fodder crops
Objective Field:Sown pastures (excl. lucerne)
UTAS Author:Rawnsley, RP (Dr Richard Rawnsley)
ID Code:53380
Year Published:2008
Web of Science® Times Cited:86
Deposited By:Agricultural Science
Deposited On:2008-12-03
Last Modified:2009-04-06

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