Effects of climate scenarios on simulated intake of sheep grazing native pastures in northern New South Wales, Australia
G. M. Lodge A D , I. R. Johnson B and B. R. Cullen CA Industry & Investment NSW, Tamworth Agricultural Institute, 4 Marsden Park Road, Calala, NSW 2340, Australia.
B IMJ Consultants, PO Box 1590, Armidale, NSW 2350, Australia.
C Melbourne School of Land and Environment, University of Melbourne, Vic. 3010, Australia.
D Corresponding author. Email: greg.lodge@industry.nsw.gov.au
Animal Production Science 49(11) 1015-1022 https://doi.org/10.1071/AN09029
Submitted: 25 February 2009 Accepted: 27 June 2009 Published: 14 October 2009
Abstract
Interpolated climate data were used as inputs for simulations in a biophysical model to predict the proportion of the total intake provided by native pasture for wethers and ewes for three climate scenarios on the North-West Slopes of New South Wales (NSW), Australia. These climate scenarios compared the 1961–90 historical baseline climate with two climate projections for 2030 based on (i) the Intergovernmental Panel on Climate Change A1B scenario in 2030 for a site near Barraba, and (ii) a report to the NSW Government indicating that the climate of Tamworth (~85 km south-east of Barraba) could become similar to that of Warialda (~95 km north-west of Barraba). A third scenario compared historical data for the Barraba location for 30-year ‘dry’ and ‘wet’ periods, in the first and second halves of the 1900s, respectively.
Model simulations indicated that the largest differences in the predicted proportion of wether and ewe intake provided by the pasture occurred for the historical ‘dry’ and ‘wet’ periods. For the reference climate normal (1961–90) v. 2030 A1B scenario and the Tamworth–Warialda comparison, there were few substantial differences in the predicted proportion of pasture intake. Additionally, there was only a small effect of a variation (up to 20%) in rainfall distribution and inter-annual variability on pasture intake by sheep. Since the largest predicted differences in sheep intake of pasture occurred for historical ‘wet’ and ‘dry’ periods, it was apparent that climate variability would continue to have a major influence on grazed native pastures on the North-West Slopes of NSW.
Additional keywords: 2030 projections, climate change, climate variability, stocking rate, Sustainable Grazing Systems Pasture Model.
Acknowledgements
Ian Johnson and Brendan Cullen were funded by Dairy Australia, Meat & Livestock Australia, AgResearch New Zealand and the University of Melbourne through the Whole Farm Systems Analysis and Tools for the Grazing Industries Project. We also thank Steven Harden, biometrician, Industry & Investment NSW, Tamworth, for his statistical advice.
Cullen BR,
Johnson IR,
Eckard RJ,
Lodge GM,
Walker R,
Rawnsley RP, McCaskill MR
(2009) Climate change effects on pasture systems in south-eastern Australia. Crop & Pasture Science 60, 933–942.
| Crossref |
[Verified 21 September 2009]
Harle KJ,
Howden SM,
Hunt LP, Dunlop M
(2007) The potential impact of climate change on the Australian wool industry by 2030. Agricultural Systems 93, 61–89.
| Crossref | GoogleScholarGoogle Scholar |
[Verified 21 September 2009]
Lodge GM,
Murphy SR, Harden S
(2003) Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 1. A redgrass-wallaby grass pasture, Barraba, North-West Slopes, New South Wales. Australian Journal of Experimental Agriculture 43, 875–890.
| Crossref | GoogleScholarGoogle Scholar |
[Verified 21 September 2009]
