A review and meta‐analysis of the agricultural potential of struvite as a phosphorus fertilizer

Abstract

The low water solubility of struvite is thought to limit its agronomic utility as a phosphorus (P) fertilizer compared with highly soluble P fertilizers. Furthermore, struvite's fertilizer potential is complicated by its hypothesized soil pH‐dependent solubility, crop‐specific interactions, and limited availability of struvite‐derived N, which may explain conflicting reports of crop responses to struvite compared with conventional P fertilizers. A systematic literature review and meta‐analysis was conducted to evaluate the effects of soil pH, soil test P (STP), P rate, struvite particle size, and struvite‐derived N on crop aboveground biomass, P concentration, P uptake, and N uptake. Struvite‐fertilized plants yielded higher biomass, P concentration, and P uptake compared with ammonium phosphates, and superphosphates in soils with pH < 6 and crop responses decreased with increasing pH. Crop responses to struvite were inversely related to experiment duration to soil mass ratios (d kg−1) used in greenhouse studies, opposite to the hypothesized benefit of more roots per unit soil on struvite dissolution. The proportion of total N applied derived from struvite increased with increasing struvite‐P application rate and was inversely related to total N uptake, likely due to the increased crop reliance on slowly available struvite‐N. Crop responses were potentially overestimated by high STP and/or P rates and underestimated due to N limitation from large proportions of total N applied derived from struvite. Evaluations of struvite collectively indicate its efficacy as a P fertilizer is affected by soil pH and its contribution to total N application.

Total extractable phosphorus in flooded soil as affected by struvite and other fertilizer‐phosphorus sources

“…Intentional struvite precipitation has become one popular method of P recovery in recent decades (Hertzberger, Cusick, & Margenot, 2020; Huygens & Saveyn, 2018). Struvite (MgNH 4 PO 4 · 6H 2 O) is a white, crystalline, solid material comprised of equal molar concentrations of magnesium (Mg 2+ ), ammonium (NH 4 + ), and phosphate (PO 4 3– ) (Hertzberger et al., 2020; Schoumans et al., 2015).…”

“…Intentional struvite precipitation has become one popular method of P recovery in recent decades (Hertzberger, Cusick, & Margenot, 2020; Huygens & Saveyn, 2018). Struvite (MgNH 4 PO 4 · 6H 2 O) is a white, crystalline, solid material comprised of equal molar concentrations of magnesium (Mg 2+ ), ammonium (NH 4 + ), and phosphate (PO 4 3– ) (Hertzberger et al., 2020; Schoumans et al., 2015). Struvite recovery has gained popularity because of the ability to simultaneously remove both P and N from solid and liquid wastes, and because of struvite's slow‐release fertilizer properties under aerobic soil conditions (Degryse, Baird, da Silva, & McLaughlin, 2016; Nascimento et al., 2018; Tallboys et al., 2016).…”

Wastewater‐recovered struvite effects on total extractable phosphorus compared with other phosphorus sources

“…Phosphorus recovery from waste materials in the form of struvite precipitation has been an area of research in recent decades (Huygens & Saveyn, 2018; Hertzberger et al., 2020). Struvite (MgNH 4 PO 4 · 6H 2 O) is a crystalline, white, solid material comprised of equal molar concentrations of phosphate (PO 4 3– ), ammonium (NH 4 + ), and magnesium (Mg 2+ ) (Schoumans et al., 2015; Hertzberger et al., 2020).…”

“…Phosphorus recovery from waste materials in the form of struvite precipitation has been an area of research in recent decades (Huygens & Saveyn, 2018; Hertzberger et al., 2020). Struvite (MgNH 4 PO 4 · 6H 2 O) is a crystalline, white, solid material comprised of equal molar concentrations of phosphate (PO 4 3– ), ammonium (NH 4 + ), and magnesium (Mg 2+ ) (Schoumans et al., 2015; Hertzberger et al., 2020). Intentional struvite precipitation has gained popularity due to the potential to remove both P and N from solid and liquid wastes and the struvite's slow‐release‐fertilizer properties (Degryse et al., 2016; Nascimento et al., 2018; Tallboys et al., 2016).…”

Electrochemically precipitated struvite effects on extractable nutrients compared with other fertilizer‐phosphorus sources

“…Recovering P from waste sources has been an area of active research over the last few decades to potentially provide a sustainable alternative to commercial P fertilizers derived from the finite supply of RP (Ahmed et al., 2018; Hertzberger et al., 2020; Huygens & Saveyn, 2018). One such potential alternative source is magnesium ammonium phosphate hexahydrate (MgNH 4 PO 4 · 6H 2 O), which is the mineral struvite.…”