Evaluation of electrochemically precipitated struvite as a fertilizer-phosphorus source in flood-irrigated rice

Phosphorus (P) is a major contaminant in many wastewater sources and has gained interest due to the role P has in eutrophication of receiving waters. Recycling P from wastewater as the mineral struvite (MgNH₄PO₄ · 6H₂O) could be a promising option to reduce P discharge into receiving waters and could potentially provide an alternative fertilizer-P source for crop production. The objective of this study was to evaluate the effects of two struvite materials (i.e., electrochemically precipitated struvite [ECST] and chemically precipitated struvite [CPST]) relative to several other common fertilizer-P sources (i.e., triple super phosphate [TSP], monoammonium phosphate [MAP], diammonium phosphate [DAP], and rock phosphate [RP]) on the response of a pureline rice (Oryza sativa L.) cultivar grown under flood-irrigation in a P-deficient, silt-loam soil (Typic Glossaqualfs) in eastern Arkansas. In 2019, rice grain yield did not differ (P >.05) among fertilizer-P sources, whereas in 2020, rice grain yield was greater from TSP (13.1 Mg ha⁻¹) than that from ESCT (11.0 Mg ha⁻¹) or CPST (12.7 Mg ha⁻¹). Rice aboveground dry matter, aboveground and belowground tissue and grain P and N concentrations, aboveground and grain tissue P uptake, and aboveground tissue N concentration from ECST and CPST did not differ (P >.05) from those from TSP, MAP, DAP, RP, or an unamended control. The similarities in rice responses compared with other commonly used, commercially available fertilizer-P sources suggest that struvite materials have the potential to be an alternative fertilizer-P source option for flood-irrigated rice production.