Presentation on theme: "Water use characteristics of irrigated crops in the southern MDB: weather-based irrigation scheduling D. Whitfield, M. O’Connell, L. McClymont A. McAllister,"— Presentation transcript:
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
Satellite-based Water Use Applications: Field/crop scale irrigation scheduling Farm/region/industry scale water use benchmarking, planning, reporting
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 requirements FAO 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
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)