Abstract: Optimising water use in a way that avoids over watering or at least avoids or minimises water mobilisation may be useful. An irrigation control system is described, the system including a sound emitter arranged to emit sound towards a ground surface; a sound receiver arranged to receive sound emitted by the sound emitter and reflected or scattered from the ground surface. A controller then controls one or more irrigation parameters of an irrigator based at least in part on sound received by the sound receiver. In a further aspect, the irrigation control system senses the onset of surface water pooling or free water flow on the ground surface and the controller then controls irrigation parameters to reduce application of water in response to the sensed features. Related methods of controlling irrigation systems are also described.