Managing spatial and temporal variability in irrigated agriculture through adaptive control

Abstract

Spatial variability in crop production occurs as a result of spatial and temporal variations in soil structure and fertility; soil physical, chemical and hydraulic properties, irrigation applications, pests and diseases, plant genetics and local microclimate. This review paper argues that infield variability can be managed and the efficiency of irrigation water use increased by spatially variable application of irrigation water to meet the specific needs of individual management zones (areas of crop whose properties are relatively homogenous). Key areas identified requiring interdisciplinary research are: the prescription of irrigated crop water requirements; strategies for quantifying and managing spatial variability; and the development of adaptive systems for control of water application at appropriate temporal intervals and spatial scales. Example strategies for the implementation of adaptive control for furrow irrigation and large mobile irrigation machines are described.