Effects of fertigation on corrosion in galvanized steel used in center pivot systems

Abstract

One of the main causes of agricultural equipment deterioration is corrosion. In center pivot irrigation systems, deterioration mainly occurs in galvanized steel pipelines. Fertigation can increase corrosion because fertilizers become corrosive when exposed to water or moisture; this corrosion reduces the service lifetime of the equipment. In this study, fertigation-induced corrosion was evaluated in specimens of galvanized steel (similar to that used in center pivot systems), simulating 10 years of operation comprising 5 fertigations per year with a duration of 7 hours each. Immersion tests were performed in solutions containing 0, 5 and 10 g/L fertilizer concentrations to obtain the mass loss per unit area of the metallic material, which increased in response to increases in both the exposure time in the corrosive environment and the fertilizer concentration. The results showed that fertigation increases corrosion in galvanized steel and the higher fertilizer concentration leads to a higher corrosion, since, for the same exposure time, the mass loss for the 10 g/L solution was 43% greater than the 5 g/L.