Methods for drip irrigation clogging detection, analysis and understanding: State of the art and perspectives

Clogging is one of the main ageing factors in drip irrigation. Clogging can be physical, chemical or biological. The adequate maintenance procedures to be applied differ according to the type of clogging involved. It is therefore noteworthy to first determine the nature and amount of clogging in the field before managing maintenance operations. Laboratory-based methods can help to understand the clogging mechanisms. However, these methods require either the extraction of samples and thus the destruction of drippers or a specific installation such as transparent flow cells to observe clogging. In the field, several methods based on hydraulic measurements can estimate the presence of clogging. However they provide an indirect estimation and do not necessarily reflect the early stages of clogging. There is currently no direct method for detecting clogging in the field in the drippers. The difficulty arises both from the variety of clogging materials to be detected and from the small section of the dripper channels of the order of 1 mm². This review analyses the pros and cons of several types of sensors (electrical, mechatronic, acoustic and optical) that offer potential perspectives to meet this need.