Post-experimental modelling of grazing systems to improve profit and environmental outcomes using AusFarm
K. M. Broadfoot A B , W. B. Badgery A and G. D. Millar AA NSW Department of Primary Industries, Orange Agricultural Institute, 1447 Forest Road, Orange, NSW 2800, Australia.
B Corresponding author. Email: kim.broadfoot@dpi.nsw.gov.au
Animal Production Science 57(9) 1849-1858 https://doi.org/10.1071/AN16129
Submitted: 1 March 2016 Accepted: 2 January 2017 Published: 13 June 2017
Abstract
Assessments of grazing systems are often constrained by the decisions regarding the management of the grazing systems, including stocking rate, and also the seasonal conditions that occur during the assessment period. These constraints have led to sometimes conflicting results about comparisons of grazing management systems. This paper examines 1-, 4- and 20-paddock (1P, 4P and 20P) grazing management systems to determine how the intensity of grazing management on native pastures influences the financial performance of sheep production systems. The performance of the grazing systems, as part of the Orange EverGraze research experiment, was initially examined using the biophysical data over the 4 years of the experiment and then a more detailed analysis over a longer timeframe was undertaken using the AusFarm simulation modelling software. Flexible management strategies to optimise ewe numbers, sale time of lambs, and adjust ewe numbers based on season, were also assessed to determine which management systems are the most profitable and sustainable. There was higher profit for the 20P grazing system than the 1P system during the experiment. However, when stocking rates were held constant at optimum levels and systems were simulated over 40 years, there was no difference between grazing systems. Modelling strategies used to vary stocking rates showed that flexible management options are better based on optimising ewe numbers and the sale time of lambs rather than changing ewe numbers between years. The sustainability of modelled systems was also assessed using frequency of events where the average herbage mass (0.8 t DM/ha) or ground cover (80%) in autumn dropped below levels that are associated with degradation. Degradation events occurred more so with increasing ewe number than lamb sale time. Overall, the most sustainable systems, when considering profitability and environmental issues, had a stocking rate of 4.2 ewes per ha, with lambs sold in February (2 or 18). Higher stocking rates (5.3 ewes/ha) would need to be run for more intensive grazing management to have higher profitability.
Additional keywords: AusFarm, flexible management, grazing management, modelling.
References
Amidy MR, Behrendt K, Badgery WB (2017) Assessing the profitability of native pasture grazing systems: a stochastic whole-farm modelling approach. Animal Production Science 57, 1859–1868.| Assessing the profitability of native pasture grazing systems: a stochastic whole-farm modelling approach.Crossref | GoogleScholarGoogle Scholar |
Badgery WB, Kemp DR, Michalk DL, King WM (2008) Studies of competition between Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock) and native pastures. 2. Seedling responses. Australian Journal of Agricultural Research 59, 237–246.
| Studies of competition between Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock) and native pastures. 2. Seedling responses.Crossref | GoogleScholarGoogle Scholar |
Badgery WB, Millar GD, Mitchell D, Cranney P, Priest SM (2010) Predicting pasture production from November temperatures. In ‘25th conference of The Grassland Society of NSW’, Dubbo. (Eds C Waters, D Garden) pp. 108–111. (The Grassland Society of NSW Inc.: Orange, NSW)
Badgery W, Michalk D, Kemp D (2015) Sustainable management of temperate grasslands in Australia. In ‘Grassland: a global resource perspective’. (Eds PK Gosh, SK Mahanta, JB Singh, PS Pathak) pp. 141–192. (Range Management Society of India: Jhansi, India)
Badgery WB, Millar GD, Michalk DL, Cranney P, Broadfoot K (2017a) The intensity of grazing management influences lamb production from native grassland. Animal Production Science 57, 1837–1848.
| The intensity of grazing management influences lamb production from native grassland.Crossref | GoogleScholarGoogle Scholar |
Badgery WB, Mitchell D, Millar GD, Broadfoot K, Michalk DL, Cranney P, Brown W (2017b) Designing a grazing-system experiment for variable native pastures and flexible lamb-production systems. Animal Production Science 57, 1785–1798.
| Designing a grazing-system experiment for variable native pastures and flexible lamb-production systems.Crossref | GoogleScholarGoogle Scholar |
Badgery WB, Millar GD, Broadfoot K, Michalk DL, Cranney P, Mitchell D, van de Ven R (2017c) Increased production and cover in a variable native pasture following intensive grazing management. Animal Production Science 57, 1812–1823.
| Increased production and cover in a variable native pasture following intensive grazing management.Crossref | GoogleScholarGoogle Scholar |
Bell LW, Harrison MT, Kirkegaard JA (2015) Dual-purpose cropping – capitalising on potential grain crop grazing to enhance mixed-farming profitability. Crop & Pasture Science 66, i–iv.
| Dual-purpose cropping – capitalising on potential grain crop grazing to enhance mixed-farming profitability.Crossref | GoogleScholarGoogle Scholar |
Chapman DF, McCaskill MR, Quigley PE, Thompson AN, Graham JF, Borg D, Lamb J, Kearney G, Saul GR, Clark SG (2003) Effects of grazing method and fertiliser inputs on the productivity and sustainability of phalaris-based pastures in Western Victoria. Australian Journal of Experimental Agriculture 43, 785–798.
| Effects of grazing method and fertiliser inputs on the productivity and sustainability of phalaris-based pastures in Western Victoria.Crossref | GoogleScholarGoogle Scholar |
Chapman DF, Rawnsley RP, Cullen BR, Clark DA (2013) Inter-annual variability in pasture herbage accumulation in temperate dairy regions: causes, consequences, and management tools. In ‘Proceedings of the 22nd international grassland congress’, Sydney. (Eds D Michalk, G Millar, W Badgery, K Broadfoot) Volume 1. pp. 798–805. (NSW DPI: Orange, NSW) Available at http://www.internationalgrasslands.org/files/igc/publications/2013/proceedings-22nd-igc.pdf [Verified 1 June 2016]
Cox F (2012) Understanding sheep grazing in native pastures to better manage production and natural resource outcomes. PhD Thesis, Charles Sturt University, Orange, NSW.
Freer M, Moore AD, Donnelly JR (1997) GRAZPLAN: decision support systems for Australian grazing enterprises. 2. The animal biology model for feed intake, production and reproduction and the GrazFeed DSS. Agricultural Systems 54, 77–126.
| GRAZPLAN: decision support systems for Australian grazing enterprises. 2. The animal biology model for feed intake, production and reproduction and the GrazFeed DSS.Crossref | GoogleScholarGoogle Scholar |
Hacker RB, Robertson MJ, Price RJ, Bowman AM (2009) Evolution of mixed farming systems for the delivery of triple bottom line outcomes: a synthesis of the Grain & Graze program. Animal Production Science 49, 966–974.
| Evolution of mixed farming systems for the delivery of triple bottom line outcomes: a synthesis of the Grain & Graze program.Crossref | GoogleScholarGoogle Scholar |
Hinch GN, Hoad J, Lollback M, Hatcher S, Marchan R, Colvin A, Scott JM, Mackay D (2013) Livestock weights in response to three whole-farmlet management systems. Animal Production Science 53, 727–739.
| Livestock weights in response to three whole-farmlet management systems.Crossref | GoogleScholarGoogle Scholar |
Hughes JD, Packer IJ, Michalk DL, Dowling PM, King WM, Brisbane S, Millar GD, Priest SM, Kemp DR, Koen TB (2006) Sustainable grazing systems for the Central Tablelands of New South Wales. 4. Soil water dynamics and runoff events for differently-managed pasture types. Australian Journal of Experimental Agriculture 46, 483–494.
| Sustainable grazing systems for the Central Tablelands of New South Wales. 4. Soil water dynamics and runoff events for differently-managed pasture types.Crossref | GoogleScholarGoogle Scholar |
Jeffrey SJ, Carter JO, Moodie KB, Beswick AR (2001) Using spatial interpolation to construct a comprehensive archive of Australian climate. Environmental Modelling & Software 16, 309–330.
| Using spatial interpolation to construct a comprehensive archive of Australian climate.Crossref | GoogleScholarGoogle Scholar |
Kemp DR, Michalk DL, Virgona JM (2000) Towards more sustainable pastures: lessons learnt. Australian Journal of Experimental Agriculture 40, 343–356.
| Towards more sustainable pastures: lessons learnt.Crossref | GoogleScholarGoogle Scholar |
Lang D, McDonald W (2005) Maintaining groundcover to reduce erosion and sustain production. NSW Department of Primary Industries. Available at http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0018/162306/groundcover-for-pastures.pdf [Verified 1 June 2016]
Lodge GM, Johnson IR (2008) Agricultural drought analyses for temperate Australia using a biophysical pasture model. 1. Identifying and characterising drought periods. Australian Journal of Agricultural Research 59, 1049–1060.
| Agricultural drought analyses for temperate Australia using a biophysical pasture model. 1. Identifying and characterising drought periods.Crossref | GoogleScholarGoogle Scholar |
Millar GD, Jones RE, Michalk DL, Brady S (2009) An exploratory tool for analysis of forage and livestock production options. Animal Production Science 49, 788–796.
| An exploratory tool for analysis of forage and livestock production options.Crossref | GoogleScholarGoogle Scholar |
Mitchell DC, Badgery WB, Cranney P, Broadfoot K, Priest S, Pickering D (2017) In a native pasture, landscape properties influence soil moisture more than grazing management. Animal Production Science 57, 1799–1811.
| In a native pasture, landscape properties influence soil moisture more than grazing management.Crossref | GoogleScholarGoogle Scholar |
Moore AD, Ghahramani A (2014) Climate change and broadacre livestock production across southern Australia. 3. Adaptation options via livestock genetic improvement. Animal Production Science 54, 111–124.
| Climate change and broadacre livestock production across southern Australia. 3. Adaptation options via livestock genetic improvement.Crossref | GoogleScholarGoogle Scholar |
Moore AD, Donnelly JR, Freer M (1997) GRAZPLAN: decision support systems for Australian grazing enterprises. 3. Pasture growth and soil moisture submodels, and the GrassGro DSS. Agricultural Systems 55, 535–582.
| GRAZPLAN: decision support systems for Australian grazing enterprises. 3. Pasture growth and soil moisture submodels, and the GrassGro DSS.Crossref | GoogleScholarGoogle Scholar |
Moore AD, Bell LW, Revell DK (2009) Feedgaps in mixed-farming systems: insights from the Grain & Graze program. Animal Production Science 49, 736–748.
| Feedgaps in mixed-farming systems: insights from the Grain & Graze program.Crossref | GoogleScholarGoogle Scholar |
NSW Department of Primary Industries (DPI) (2011) Merino ewes (20 micron) – terminal rams: farm enterprise budget series – April 2011. Industry and Investment NSW. Available at http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0003/175854/merino-ewes-20-micron-terminal-rams.pdf [Verified 1 June 2016]
Payne R, Murray D, Harding S, Baird D, Soutar D (2013) ‘Introduction to GenStat® for WindowsTM.’ 16th edn. (VSN International: Hemel Hempstead, Hertfordshire)
Scott JM, Hutchinson KJ, King K, Chen W, McLeod M, Blair GJ, White A, Wilkinson D, Lefroy RDB, Cresswell H, Daniel H, Harris C, MacLeod DA, Blair N, Chamberlain G (2000) Quantifying the sustainability of grazed pastures on the Northern Tablelands of New South Wales. Australian Journal of Experimental Agriculture 40, 257–265.
| Quantifying the sustainability of grazed pastures on the Northern Tablelands of New South Wales.Crossref | GoogleScholarGoogle Scholar |
Sollenberger LE (2015) Challenges, opportunities and applications of grazing research. Crop Science 55, 2540–2549.
| Challenges, opportunities and applications of grazing research.Crossref | GoogleScholarGoogle Scholar |
Warn LK, Frame HR, McLarty GR (2002) Effects of grazing method and soil fertility on stocking rate and wool production. Wool Technology and Sheep Breeding 50, 510–517.
Watt BR, Bird TL (1998) Economic comparison of centre plus merino and first-cross ewes as prime lamb dams. Animal Production in Australia 22, 241–244.
