The discussion centers on the types of phosphates used in fertilizers, primarily focusing on orthophosphate and its prevalence. While some participants assert that orthophosphate is the main form used, others highlight the complexity of phosphate types in fertilizers. Historically, "superphosphate," a combination of gypsum and monocalcium phosphate, was common, but the industry has largely transitioned to "triple superphosphate," produced by treating insoluble calcium phosphate with phosphoric acid. Both superphosphate and triple superphosphate yield chemically similar products, specifically Ca(H2PO4)2. Additionally, ammonium phosphate is mentioned as another variant. A participant notes a correlation between the shift to triple superphosphate and lawn issues in San Antonio, suggesting a potential link to the phosphate type, although this claim remains debated. The conversation emphasizes the diversity of phosphate sources in fertilizers and the implications for agricultural practices.
