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Transcript of Idenitifying the fit for perennial forage options in a crop-livestock system: use of a whole-farm...
Identifying the fit for perennial forage options in a crop-livestock system: use of a whole-farm optimization model
Marta Monjardino,
R. Llewellyn and A. Bathgate
5th World Congress of Conservation Agriculture Brisbane, 26-29 September 2011
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
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
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
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
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;
0
10
20
30
40
50
60
70
Rai
nfal
l (m
m) &
tem
pera
ture
('C
)
Rainfall
Temperature
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
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
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
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
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 stand
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
Land management units
LMU Main soil type Description W yield potential
Shrub potential
U/s medic pasture
potential
1234567
Sandy loamSandyCalc, stonyInterm. SoilsDeep sandsLo o/ clay (w/ ssc)Lo o/ clay (no ssc)
Reliable, ↑ yieldsSame, but fert req.↓ yld, wears mach.Med yieldsErosion, ↓ yields↓↓ yld in dry spring↓ yld in dry spring
2.01.80.41.60.80.61.4
100%70%50%90%50%65%90%
100%67%10%67%17%40%
>100%
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
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
0 10 20 30 40 50 60
0
500
1000
1500
2000
LMU 7
LMU 6
LMU 5
LMU 4
LMU 3
LMU 2
LMU 1
Shrub %
Sh
rub
are
a (h
a)
Standard output
Crop area (% of farm)Pasture area (% of farm)Shrub area (% of farm)Stocking rate (DSM/ha of farm)Supplementary grain feed (kg/DSE/yr)Groundwater recharge (mm/ha/yr)Topsoil loss by erosion (m3/ha/yr) Profit ($/ha/yr)
56440
2.465
17490
129
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
Key model parameters
Parameters Std
Saltbush density (plants/ha)Saltbush nutritive value (MJ ME/kg DM)Saltbush biomass production (kg DM/plant)Saltbush anti-nutritional effects on intake (%)Saltbush establishment cost ($/plant)Price of wheat ($/t ASW)Price of wool (c/kg clean WMI)Price of prime lamb ($/kg DW)
1500713
0.4280900
4
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
Key model parameters - SA
Parameters Min Std Max
Saltbush density (plants/ha)Saltbush nutritive value (MJ ME/kg DM)Saltbush biomass production (kg DM/plant)Saltbush anti-nutritional effects on intake (%)Saltbush establishment cost ($/plant)Price of wheat ($/t ASW)Price of wool (c/kg clean WMI)Price of prime lamb ($/kg DW)
00.2180700
3
1500713
0.4280900
4
3000103
4801100
6
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
Change in whole-farm profit with increasing % saltbush shrubs.
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
0 10 20 30 40 50 60
0
200000
400000
600000
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
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
0 10 20 30 40 50 60
0
200000
400000
600000
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
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
0 10 20 30 40 50 60
0
200000
400000
600000
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
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
0 10 20 30 40 50 60
0
200000
400000
600000
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
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
0 10 20 30 40 50 60
0
200000
400000
600000
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
<10% shrub area => small decline in profit; >10% shrub area => sharp decline in profit
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
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
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
0 10 20 30 40 50 60
0
200000
400000
600000
3 kg DM/plant
2 kg DM/plant
1 kg DM/plant
0.5 kg DM/plant
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
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
0 10 20 30 40 50 60
0
200000
400000
600000
3 kg DM/plant
2 kg DM/plant
1 kg DM/plant
0.5 kg DM/plant
Shrub %
Wh
ole
-far
m p
rofi
t ($
/yea
r)
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
0 10 20 30 40 50 60
0
200
400
600
800
Deepflow
Erosion
Shrub %
Un
its/
/ha/
yr
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
0 10 20 30 40 50 60
0
200
400
600
800
Deepflow
Erosion
Shrub %
Un
its/
/ha/
yr
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
0 10 20 30 40 50 60
0
200
400
600
800
Deepflow
Erosion
Shrub %
Un
its/
/ha/
yr
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
0 10 20 30 40 50 60
0
200
400
600
800
Deepflow
Erosion
Shrub %
Un
its/
/ha/
yr
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
0 10 20 30 40 50 60
0
200
400
600
800
Deepflow
Erosion
Shrub %
Un
its/
/ha/
yr
0 10 20 30 40 50
0
200
400
600
800
Shrub %
mm
//h
a/yr
Conclusions
1. 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
Conclusions
1. 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
Conclusions
1. 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
CSIRO. Identifying the fit for forage shrubs in a crop-livestock system: use of a whole-farm optimization model
Photo source: Enrich project
Contact UsPhone: 1300 363 400 or +61 3 9545 2176
Email: [email protected] Web: www.csiro.au
Thank you!
CSIRO Ecosystem SciencesDr. Marta Monjardino
Phone: 61 (0)8 8303 8413Email: [email protected]: www.csiro.au/ces
Acknowledgements Future Farm Industries CRCGRDC