Improving the efficiency of water use in agriculture is increasingly essential to maintain the

profitability and sustainability of farms. This involves applying only the minimum necessary

irrigation water to maintain or improve the yield of individual plants. Irrigation control strategies can

be used to improve site-specific irrigation. These control strategies generally require weather, plant

and/or soil data to determine irrigation volumes and/or timing that improve crop water use efficiency

while maintaining or improving crop yield. As the plant response and environmental conditions

fluctuate throughout the season, control strategies which accommodate temporal and spatial

vanability in the field and which locally modify the control actions (irrigation amounts) need to be

'adaptive'. Such irrigation control systems may then be implemented on large mobile irrigation

machine, both 'lateral move' and 'centre pivot' configurations, to provide automatic machine

operation

A simulation framework 'VANwise' has been created to aid the development, evaluation and

management of spatialIy and temporalIy varied site-specific irrigation control strategies. The cotton

model OZCOT has been integrated into VANwise to provide feedback data in the control strategy

simulations. VANwise can accommodate sub-field scale variations in allinput parameters using a

one square metre cell size, and permits application of differing control strategies within the field, as

well as differing irrigation amounts down to this scale. An automatic model calibration procedure

was also developed for VARlwise to enable real-time input of field data into the framework. The

model calibration procedure was accurately implemented with measured field data and the calibrated

model was then used to evaluate the effect of using different data inputs in an irrigation control

system.