variability in a WA example Single year and Inferred (many Complex No data No data – multi-year yield factors influence maps yield) (many factors influence yield which integrates all processes acting on crops) Soil survey Inferred Process-based No data No data (pedotransfer functions may generate indicative K requirement map based on particular soil properties) Radiometrics Composite Simple Data collection Wong and – (directly Process-based method Harper measures total determines (K tot. can be K in topsoil and scale of directly correlated can infer other reliability to K exch in some topsoil situations properties) May not be sensitive enough to establish plant response levels) Measures integrated processes EM Inferred Complex – No data No data Process-based functions may generate indicative K requirement map based on particular soil properties) mid-season Inferred Process Wong, Corner mid-season NDVI and Cook NDVI (2001)
variability in a WA example Single year and multi-year yield maps Inferred (many factors influence yield) Complex – (many factors influence yield which integrates all processes acting on crops) No data No data Soil survey Inferred (pedotransfer functions may generate indicative K requirement map based on particular soil properties) Process-based No data No data Radiometrics Composite (directly measures total K in topsoil and can infer other topsoil properties) Simple – Process-based (K tot. can be directly correlated to K exch in some situations May not be sensitive enough to establish plant response levels) Measures integrated processes Data collection method determines scale of reliability Wong and Harper EM Inferred functions may generate indicative K requirement map based on particular soil properties) Complex – Process-based No data No data mid-season NDVI Inferred Process Wong, Corner and Cook (2001) mid-season NDVI
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