Multi-factorial failure of pressure-compensating emitters in drip fertigation systems: An in-situ sampling investigation

Abstract

Pressure-compensating emitter (PCE) is an important equipment to improve irrigation and fertigation uniformity of drip irrigation system. Due to multiple factors, PCE failure would lead to the whole drip irrigation system failure and consequently affect the crop growth. However, few studies reported the key reason and influential factors of PCE failure yet. Therefore, an in-situ sampling study of PCE, which was collected from 16 different operating locations and all were operated for several years in the apple orchard, was conducted in this paper. The effects of water quality characteristics and climatic conditions on the fouling formation inside PCE and the mechanical properties of the elastic diaphragm were analyzed. The result indicated that the PCE relative average discharge (Dra) decreased by 4.65%− 33.19% after 3–9 years. The phosphorus content, average temperature, suspended particles, and pH showed significant impacts on fouling accumulation inside the PCE flow channel, particularly biofouling. Meanwhile, the stretch rate, elastic modulus, tensile strength, and the hardness of PCE elastic diaphragm were mainly affected by humidity conditions, longitude, SO42- content and pH. Both the fouling accumulation and elastic diaphragm variations synthetically decreased the Dra of the drip irrigation system. This study provides theoretical support to further improve the irrigation uniformity of drip irrigation systems.