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A presentation from the WCCA 2011 event held in Brisbane, Australia.
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Department of Employment, Economic Development and Innovation
The expected value of seasonal stream-flow forecasts to a grain-cotton irrigator in the Condamine-Balonne catchment.
Brendan Power, Daniel Rodriguez, Jeff Perkins and Claire Hawksworth
2© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
• Seasonal stream flow forecasts • Whole-farm economic modelling of
irrigated grain/cotton farms with APSIM
• Case study results
Overview
3© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
www.bom.gov.au/water/ssf
Seasonal streamflow forecasts
4© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Forecast skill
5© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
What is APSIM?
A farming systems model created …• to model the farming system performance over
time• with equal emphasis on crop and soil
dimensions of agricultural systems• with a capability to deal comprehensively with
management – e.g. planting times, N, irrigation
• wide scope of application, from genetics (breeding) through farming systems to policy.
6© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
APSIM
Soilwat
SoilN
SurfaceOM
ChickpeaMaize
Wheat
SoilPH
SoilWat
SWIM
SoilP
Erosion
Manager
Paddock
7© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Pump cap.
Economics
Met
Manager
paddock7Soil
Weeds
Residue
Crops
paddock6 Soil
Weeds
Residue
Crops
Farm
paddock2 paddock3
SoilwatSoil
Residue
paddock8
Crops
paddock5Soil
SoilN
Residue
paddock4
Soil
Weeds
Crops
Crops
Weeds
Residue
Soil
Weeds
Crops
Residue
Soil
Weeds
Residue
Crops
paddock1Soil
Weeds
Crops
Residue
Water sources
Waters storages
Weeds
Irrigated APSIM farms
8© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Planting window: Sep 15 – Oct 15Stored water > 4ML/ha
Existing farm area planted to maize or sorghum less than 50%
Planting window: Oct 16 – Jan 15Rain over 4 days > 25mm
ESW > 150mmmaize or sorghum area < 50% Oct 15 – Nov15
Stored water > 4ML/hacotton area < 50%
Case studies
9© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Validation
10© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Validation
11© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Dalby case study farm
Dalby
12© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Dalby case study farm
• Total cropping area - 615ha• Furrow irrigation• 3 Storages - 2400 ML at 70ML/day• Sources of water
– On-farm runoff– Off-farm overland flow ~tr(0,200,400) ML/yr– Bores (172ML/yr at 12ML/day)– River flow
13© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
IQQM modelled Condamine river flow
14© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
• Streamflow forecasts not currently available in QLD (available from July 2012)
• The NINO3 index with a 2 month lag has the best skill at predicting summer (DJF) rainfall at Dalby (Schepen et al., 2011) .
• NINO3 index used as a proxy forecast for Condamine River flows.
Proxy streamflow forecasts
15© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Summer (DJF) rainfall
Positive forecastNegative forecastNo forecast
Rainfall (mm)
Pro
babi
lity
Summer (DJF) river flows
Positive forecastNegative forecastNo forecast
River flow (ML)
Pro
babi
lity
Oct NINO3 index
16© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Change in management• Vary cotton area based on the streamflow prediction• Assumed monoculture cotton for simplicity• Cotton area depends on the amount of stored water at
sowing• Optimised the cotton sowing rule based on NINO3
values w.r.t. required stored water (ML/ha) at sowing.• Results:
– Positive NINO3 predictions - 0 ML/ha (ie plant entire farm to cotton)
– Negative NINO3 – no change in management (ie 4 ML/ha)
– 20 out of 51 years predicted high river flows.
17© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Results
Current managementAdaptive management
High flow seasons
AU$31,000/year
Current managementAdaptive management
All seasons
18© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
What next?
• Realistic crop rotations• Implication for risk• Different farms and rivers • Out-of-sample tests• Environmental trade-offs
19© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
Summary:• Seasonal stream flow forecasts • Whole-farm economic modelling of
irrigated grain/cotton farms with APSIM
• Case study results
20© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011
References• Australian Bureau of Meteorology (2010) Information sheet 9 Streamflow
forecasting: Days to seasons, Australian Government, retrieved from www.bom.gov.au/water/about/publications/document/InfoSheet_9.pdf
• Hammer GL, Nicholls N, Mitchell C (2000) Applications of Seasonal Climate Forecasting in Agricultural and Natural Ecosystems: The Australian Experience. Kluwer Academic,
• Power B, Rodriguez D, deVoil P, Harris G, Payero J (2011) A multi-field bio-economic model of irrigated grain-cotton farming systems. Field Crop Res.
• Schepen A, Wang QJ, Robertson D, (2011) Evidence for using climate indices to forecast Australian seasonal rainfall, J. Climate.
• The State of Queensland (DERM) (2010). Integrated Quantity and Quality Model (IQQM) output data for the Condamine Balonne ROP www.derm.qld.gov.au
Thanks.