Wastewater-recovered struvite evaluation as a fertilizer-phosphorus source for corn in eastern Arkansas

The perception of wastewater as a resource rather than a pollutant has not been well emphasized. Phosphorus (P) can be precipitated from wastewaters as the mineral struvite (MgNH₄PO₄·6H₂O), which can be a potential sustainable alternative to the limited, rock phosphate (RP)-dependent, traditional fertilizer-P sources for agricultural production. This field study evaluated the effects of electrochemically precipitated struvite (ECST) and chemically precipitated struvite (CPST) compared with other conventional fertilizer-P materials (monoammonium phosphate [MAP], diammonium phosphate [DAP], triple superphosphate [TSP], and RP) on corn (Zea mays L.) response in two consecutive growing seasons in a P-deficient, silt-loam soil (Aquic Fraglossudalf) in eastern Arkansas. Averaged across years, corn yield was numerically largest from ECST (12.9 Mg ha^–1), which differed (P <.05) from all other treatments and was numerically smallest from DAP (10.1 Mg ha^–1), which was similar to MAP (10.7 Mg ha^–1), CPST (10.3 Mg ha^–1), and RP (10.3 Mg ha^–1). Corn yield and kernel P uptake from ECST were at least 1.2 times greater (P <.05) than from CPST, TSP, DAP, and RP. Yield from ECST was 1.2 times greater (P <.05) than from MAP. A partial budget analysis showed that, across both years, fertilizer-P treatment net revenues for ECST were greater than those associated with the other fertilizer-P sources. Results demonstrated that wastewater-recovered struvite materials have the potential to be a sustainable source of P for corn production in P-deficient, silt-loam soil from both a technical and economic perspective.