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Idenitifying the fit for perennial forage options in a crop-livestock system: use of a whole-farm optimization model. Marta Monjardino
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Idenitifying the fit for perennial forage options in a crop-livestock system: use of a whole-farm optimization model. Marta Monjardino

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A presentation from the WCCA 2011 event held in Brisbane, Australia.

A presentation from the WCCA 2011 event held in Brisbane, Australia.

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  • 1. Identifying the fit for perennial forage optionsin a crop-livestock system: use of a whole-farm optimization modelMarta Monjardino,R. Llewellyn and A. Bathgate5th World Congress of Conservation AgricultureBrisbane, 26-29 September 2011
  • 2. Background• Major economic and environmental challenges in low rainfall zones of southern Australia;• Forage shrubs may help fill the long feed gap in the Mallee and provide other benefits;• But are they profitable?• Use of a bio-economic tool to help identify where in the landscape and at what level of production/quality they might be profitable.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 3. Background• Major economic and environmental challenges in low rainfall zones of southern Australia;• Forage shrubs may help fill the long feed gap in the Mallee and provide other benefits;• But are they profitable?• Use of a bio-economic tool to help identify where in the landscape and at what level of production/quality they might be profitable.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 4. Forage shrubs in the Mallee• Old Man Saltbush (Atriplex nummularia) the most widely available commercial shrub species;• Low % of farmers adopting shrubs and only <1% of farm area with shrub plantings due to relatively low quality/production;• Opportunities to identify/develop new OMS and other shrub types, arrangements and mixes for higher performance;• Whole-farm model needed as perennials will always be a niche land area, but have whole-farm impact via livestock, etc;• Whole-farm considerations to help shape R&D strategies.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 5. MIDAS• Model of an Integrated Dryland Agricultural System;• Whole-farm optimization model;• Based on LP technique;• Deterministic model;• Annual equilibrium structure;• Interactions between enterprises;• Thousands of input parameters;• Detailed model output;• Software: EXCEL spreadsheets + LINDO algorithm;• Good coverage of southern Australia agro-ecological regions with several model versions in 4 states.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 6. Mallee MIDAS overview• Typical 3000 ha crop/livestock farm;• Average annual rainfall: 250-350 mm (80% in winter);• Average summer max daily temp. >30ºC;• 7 LMUs with ≠ prod. potential in typical dune-swale land system;• Crops: wheat, barley, triticale, canola, lupins, range of legumes;• Options for fallow and cereal grazing;• Merino/crossbred sheep dominant livestock for wool and meat;• Grazing on annual (medic), perennial (lucerne), vol. pastures;• Woody perennial options: forage shrubs, tree alleys; 70 Rainfall Rainfall (mm) & temperature (C) 60 50 Temperature 40 30 20 10 0 v n n l c g p r ar b ct ay Ju Ap No Ja Ju Au Se De Fe O M MCSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 7. Mallee MIDAS overview• Over 200 crop-pasture rotations + inter-rotational effects;• Ten pasture growing periods/year;• Ten major feeding periods/year;• Five supplementary feeding options;• Over 80 sheep classes;• Different management options/class;• Different energy and intake volume/class;• Deferment of pasture grazing between growing periods, and degeneration of feed over summer;CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 8. Mallee MIDAS overview• Several grain, stubble and wool quality classes;• Soil N balance and fertilization options;• Chemical control of diseases, pests and weeds;• Groundwater recharge and surface water run-off;• Loss of top soil by erosion;• Machinery specifications;• Labour requirements;• Farm finance.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 9. Validation• Difficult validation of optimization models;• Extensive process of verification;• Expert assessment of input parameters and k.p.i. (e.g. whole- farm profit, crop/pasture %, SR, rotations/LMU);• Comparison with actual farming practice;• Many issues analyzed with MIDAS/MUDAS over 3 decades, e.g.: • New crops in rotation, e.g. lupins, canola; • Saltland pastures; • Trees and shrubs; • Soil management, e.g. deep ripping; • Impact of agric. policies, e.g. salinity tax, C price; • Livestock breeds, e.g. Awassi, Dorper; • Livestock management, e.g. time of lambing; • Impact of grain quality; • Machinery changes; • Conservation strategies, e.g. stubble retention.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 10. Modelling shrub-based systems• Biological traits • Productive life of the stand • Shrub density • Shrub growth rate/biomass production • Re-establishment period • Nutritive value and anti-nutritional effects • Proportion of understorey pasture• Animal impact • Liveweight gains due to permanent feed on offer • Increased lambing rate from extra shade and shelter• Environmental impact • Groundwater recharge • Top soil loss by erosion• Costs • Establishment /maintenance of shrub standCSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 11. Land management unitsLMU Main soil type Description W yield Shrub U/s medic potential potential pasture potential 1 Sandy loam Reliable, ↑ yields 2.0 100% 100% 2 Sandy Same, but fert req. 1.8 70% 67% 3 Calc, stony ↓ yld, wears mach. 0.4 50% 10% 4 Interm. Soils Med yields 1.6 90% 67% 5 Deep sands Erosion, ↓ yields 0.8 50% 17% 6 Lo o/ clay (w/ ssc) ↓↓ yld in dry spring 0.6 65% 40% 7 Lo o/ clay (no ssc) ↓ yld in dry spring 1.4 90% >100%CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 12. 2000 1500 Shrub area (ha) LMU 7 LMU 6 1000 LMU 5 LMU 4 LMU 3 LMU 2 500 LMU 1 0 0 10 20 30 40 50 60 Shrub % Area of shrubs allocated to each LMU as they increase on the farm.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 13. Standard outputCrop area (% of farm) 56Pasture area (% of farm) 44Shrub area (% of farm) 0Stocking rate (DSM/ha of farm) 2.4Supplementary grain feed (kg/DSE/yr) 65Groundwater recharge (mm/ha/yr) 174Topsoil loss by erosion (m3/ha/yr) 90Profit ($/ha/yr) 129CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 14. Key model parametersParameters StdSaltbush density (plants/ha) 1500Saltbush nutritive value (MJ ME/kg DM) 7Saltbush biomass production (kg DM/plant) 1Saltbush anti-nutritional effects on intake (%) 3Saltbush establishment cost ($/plant) 0.4Price of wheat ($/t ASW) 280Price of wool (c/kg clean WMI) 900Price of prime lamb ($/kg DW) 4CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 15. Key model parameters - SAParameters Min Std MaxSaltbush density (plants/ha) 1500 3000Saltbush nutritive value (MJ ME/kg DM) 7 10Saltbush biomass production (kg DM/plant) 1 3Saltbush anti-nutritional effects on intake (%) 0 3Saltbush establishment cost ($/plant) 0.2 0.4Price of wheat ($/t ASW) 180 280 480Price of wool (c/kg clean WMI) 700 900 1100Price of prime lamb ($/kg DW) 3 4 6CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 16. 600000 Whole-farm profit ($/year) 400000 200000 0 0 10 20 30 40 50 60 Shrub % Change in whole-farm profit with increasing % saltbush shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 17. 600000 Whole-farm profit ($/year) 400000 200000 0 0 10 20 30 40 50 60 Shrub % Change in whole-farm profit with increasing % saltbush shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 18. 600000 Whole-farm profit ($/year) 400000 200000 0 0 10 20 30 40 50 60 Shrub % Change in whole-farm profit with increasing % saltbush shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 19. 600000 Whole-farm profit ($/year) 400000 200000 0 0 10 20 30 40 50 60 Shrub % Change in whole-farm profit with increasing % saltbush shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 20. 600000 Whole-farm profit ($/year) 400000 <10% shrub area => 200000 small decline in profit; >10% shrub area => sharp decline in profit 0 0 10 20 30 40 50 60 Shrub % Change in whole-farm profit with increasing % saltbush shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 21. Impact of different saltbush plant density levels and establishment costs on whole-farm profit with higher % shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 22. Impact of different saltbush plant density levels and establishment costs on whole-farm profit with higher % shrubs.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 23. 600000 Whole-farm profit ($/year) 400000 3 kg DM/plant 2 kg DM/plant 1 kg DM/plant 200000 0.5 kg DM/plant 0 0 10 20 30 40 50 60 Shrub % Impact of different saltbush biomass production and nutritive value levels on whole-farm profit as % shrubs increases on the farm.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 24. 600000 Whole-farm profit ($/year) 400000 3 kg DM/plant 2 kg DM/plant 1 kg DM/plant 200000 0.5 kg DM/plant 0 0 10 20 30 40 50 60 Shrub % Impact of different saltbush biomass production and nutritive value levels on whole-farm profit as % shrubs increases on the farm.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 25. 800 600 Units//ha/yr 400 Deepflow Erosion 200 0 0 10 20 30 40 50 60 Shrub % Impact of prime lamb price change on whole-farm profit for a range of shrub areas.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 26. 800 600 Units//ha/yr 400 Deepflow Erosion 200 0 0 10 20 30 40 50 60 Shrub % Impact of prime lamb price change on whole-farm profit for a range of shrub areas.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 27. 800 600 Units//ha/yr 400 Deepflow Erosion 200 0 0 10 20 30 40 50 60 Shrub % Impact of wheat price change on whole-farm profit for a range of shrub areas.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 28. 800 600 Units//ha/yr 400 Deepflow Erosion 200 0 0 10 20 30 40 50 60 Shrub % Impact of wheat price change on whole-farm profit for a range of shrub areas.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 29. 800 800 600 600 Units//ha/yr mm//ha/yr 400 400 Deepflow Erosion 200 200 0 0 0 0 10 10 20 30 20 40 30 50 60 40 50 Shrub %Shrub % Changes in ground water recharge (mm/ha/yr) with an increasing shrub area on the farm.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 30. Conclusions1. At current production/quality levels, shrubs are marginally profitable at up to 10% of farm, i.e. shrubs in the Mallee can be introduced on small farm areas (≤ 10%) with minimal loss in profit.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 31. Conclusions1. At current production/quality levels, shrubs are marginally profitable at up to 10% of farm, i.e. shrubs in the Mallee can be introduced on small farm areas (≤ 10%) with minimal loss in profit.2. Profitability of forage shrubs depends on opportunity cost of giving up other farm enterprises in the poorer farm soils;CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 32. Conclusions1. At current production/quality levels, shrubs are marginally profitable at up to 10% of farm, i.e. shrubs in the Mallee can be introduced on small farm areas (≤ 10%) with minimal loss in profit.2. Profitability of forage shrubs depends on opportunity cost of giving up other farm enterprises in the poorer farm soils;3. The current profit shortfall may well be made up through: • R&D to improve increases in shrub quality/production, as well as more effective shrub mixes/arrangements; • Lower shrub establishment costs; • Capturing of other benefits such as GHG emissions reduction (C seq. and lower CH4 via bioactive compounds), animal health/performance, improved soil condition, biodiversity, labour management, and spread of farm risk. • A change in market prices, e.g. lower grain and higher animal prod. prices.CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 33. Photo source: Enrich projectCSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
  • 34. CSIRO Ecosystem Sciences AcknowledgementsDr. Marta Monjardino Future Farm Industries CRC GRDCPhone: 61 (0)8 8303 8413Email: marta.monjardino@csiro.auWeb: www.csiro.au/cesThank you! Contact Us Phone: 1300 363 400 or +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au