Wastewater-recycled struvite as a phosphorus source in a wheat-soybean double-crop production system in eastern Arkansas

Fertilizer-phosphorus (P) sources are mainly derived from rock phosphate (RP), which is a finite, actively mined resource. With growing human populations globally, alternative P sources are vitally important to ensure future food security. Precipitation of the mineral struvite (MgNH4PO4 center dot 6H(2)O) from wastewater could be a potential alternative fertilizer-P option from crop production. The objective of this study was to evaluate the effects of chemically precipitated struvite (CPST), compared with triple superphosphate (TSP) and an unamended control (UC) treatment, and irrigation (irrigated and non-irrigated/dryland) on above- (dry matter, yield, and tissue-N, -P, and -Mg concentrations and uptake) and belowground (root tissue N, P, and Mg concentrations) soybean [Glycine max (L.) Merr.] and wheat (Triticum aestivum L.) response in a wheat-soybean, double-crop production system on a silt-loam soil (Aquic Fraglossudalfs) in eastern Arkansas. Soybean aboveground and wheat belowground Mg concentrations were 1.1 and 1.2 times, respectively, greater (p < .05) from CPST than from TSP, while soybean belowground Mg and wheat stem P concentrations were similar between CPST and TSP. Wheat stem Mg and belowground N concentrations were 1.1 times greater (p < .05) from TSP than from CPST. Soybean seed P and Mg concentrations were 1.2 and 1.1 times, respectively, greater (p < .05) under irrigated than under dryland management. Results substantiate the use of CPST as a potential alternative fertilizer-P and -Mg source on a silt-loam soil for crop production. Using wastewater-recovered nutrients in a production-scale setting may offset the need for energy-intensive commercial fertilizers to supply essential plant nutrients.