A planning strategy for sprinkler-based variable rate irrigation

Automated variable rate irrigation (VRI) is one of the frontiers for sustainable water use in agriculture. In this paper, we describe a planning procedure for self-propelled rain gun sprinklers, a type of equipment largely used in irrigation of open field crops thanks to its relatively low cost and easy deployment in multiple sites. The sprinkler is commanded by an information system which acquires data from remote sensors (satellite), processes vegetation indices and spatial maps describing the water need of the crop, and computes a VRI prescription map for a specific field, i.e. the water quantity to be supplied to each field sub-area. The VRI prescription map is used to compute the motion commands for a rain gun system pulled by a hose reel. The procedure is based on a sprinkler model, has been validated by simulation, and is fully automated. Experiments have shown the precision in water distribution achievable with software-controlled sprinklers and effective planning strategies.