Water use characteristics of irrigated crops in the southern MDB: weather-based irrigation scheduling D. Whitfield, M. O’Connell, L. McClymont A. McAllister, M. Abuzar, K. Sheffield
Feb 24, 2016
Water use characteristics of irrigated crops in the southern MDB:
weather-based irrigation scheduling D. Whitfield, M. O’Connell, L. McClymontA. McAllister, M. Abuzar, K. Sheffield
Satellite-based Water Use Applications:
• Field/crop scale irrigation scheduling • Farm/region/industry scale water use benchmarking, planning, reporting
crop type, weather (ETo)
Kc : crop type, condition/status
SUPPLY = CROP DEMAND (± LF)
CROP DEMAND: CWR = Kc ETo
Irrigation Water Use:
SUPPLY: irrigation, rainfall
long-running questions associated with both Kc and ETo in Australia:
Highly structured, discontinuous tree/vine crops (stone/pome fruits, vine, nut and citrus) are major crops in Riverland, Sunraysia, GMID:
CROP DEMAND: CWR = Kc ETo
Meyer, WS (1999):Standard Reference Evapotranspiration calculation for inland SE Australia.CSIRO Land and Water Tech Report 35/98
Allen RG, Walter, IA, Elliott RL, Howell, TA, Itenfisu D; Jensen, ME & Snyder RL (2005):The ASCE Standardized Reference Evapotranspiration Equation
Allen RG, Pereira LS, Raes D & Smith M (1998):Crop evapotranspiration - Guidelines for computing crop water requirementsFAO Irrigation and drainage paper 56
ETo: the most appropriate measure of reference crop evapotranspiration?
DEPI/NWI Water Use Measurement, Monitoring, Reporting project:
applied satellite-based SEBAL-METRIC measures to major crops grown in major irrigation districts of MDB in period, 2007-2010.
Aims:• Characterise water use of irrigated crops in MDB
• implications for improved irrigation water management, reporting, planning.
Methods:Kc approach (FAO56, ASCE-EWRI):
• Quantitative. • Scalable, with consistent application of supply/demand principles across the
range of areal and time scales relevant to irrigation water management and planning at field-farm/regional-industry scales.
Methods (cont.):
• METRIC developed by Allen et al (from SEBAL)• water use characteristics of all major crops in major irrigation areas of
southern MDB • Compare Australian crops with existing Allen Idaho data: Tasumi et al
(2005) related METRIC ET to vegetation cover (NDVI) in Idaho crops
GV dairy pasture
ET/ETr
GV dairy pasture
ET/ETo
3 classes crop water use in southern MDB:
Stone/pome, citrus, grape, nut
Perennial dairy pastures
Rice
• Strong increase in ET/ETr with increase in NDVI• ETmax = ETr
• Strong increase in ET/ETr with increase in NDVI• ETmax = ETo
• ET/ETr = 1 pre-emergence• ET/ETr < 1 post-emergence• ETmax = ETr in full-grown crop
Class 1 well-watered crops (ET/ETr > irr refill line):
Kc depends on canopy cover (NDVI):Kc = ET/ETr
Project: crop-specific relationships between crop water use (ET, CWR), weather(ETr) and vegetation cover (NDVI).
Soil water balance – irrigation scheduling
Can therefore provide satellite-based field-scale irrigation scheduling advice/services based on weather data, satellite ET, and vegetation data (NDVI)
VicDEPI FarmWeb Irrigation scheduling
Soil water balance – irrigation schedule
NDVI + weather Satellite-based irrigation schedule