With the increasing awareness of fertilizer effects on environmental and soil quality, soil tests are being conducted. In-field phosphate sensors have been a topic of heavy research since the early 1980s. It provides sustainable alternatives to more time consuming and costly laboratory analyses. Phosphate sensors can be used in agricultural and site-specific crop management to optimize application of fertilizers and minimize contamination of rainfall runoff. The main limitation in the development of phosphate sensors is selectivity. Another drawback in the development of phosphate sensors is lifetime. Further research is needed to address these problems and make in-field phosphate sensors more widely available.