Author(s)

Tatum Simms¹, Kristofor R. Brye^1*, Trenton L. Roberts¹, Lauren F. Greenlee²

¹Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR, USA.
²Department of Chemical Engineering, Pennsylvania State University, University Park, PA, USA.

Studies have shown that phosphorus (P) recovered from wastewater as the mineral struvite [MgNH₄PO₄·6(H₂O)] may be a viable alternative fertilizer-P source. This study aimed to compare the effectiveness of electrochemically precipitated struvite (ECST), reclaimed from synthetic wastewater, to other commercial fertilizer-P sources in cultivated soils from Arkansas [AR; silt loam (SiL) and loam (L)], Missouri (MO; SiL), and Nebraska [NE; SiL and sandy loam (SL)]. A plant-less, moist-soil incubation experiment, including ECST, chemically precipitated struvite (CPST), monoammonium phosphate (MAP), triple superphosphate (TSP), and an unamended control (UC), was conducted to quantify soil pH, nitrate (NO₃-N), ammonium (NH₄-N), and Mehlich-3 (M3)-P, -Ca, -Mg, and -Fe concentrations at 0.5, 1, 2, 4, and 6 months. All measured soil properties differed (P < 0.05) among fertilizer-P sources within soils over time. Soil-fertilizer combinations generally had an acidifying effect over time, with pH change from the initial lower at 6 than at 0.5 months and lower than the initial soil pH. Soil NO₃-N generally increased among fertilizer-P sources, ranging from an increase of 10.1 to 221 mg·kg^-1 for AR-L-TSP after 1 month and NE-SiL-MAP after 6 months, respectively. Soil M3-P ranged from -29.6 mg·kg^-1 in the AR-L-UC after 1 month to 429 mg·kg^-1 AR-SiL-TSP after 0.5 months. Results showed that, over time, ECST had comparable pH and soil NO₃-N, NH₄-N, and M3-P, -Ca, -Mg, and -Fe behavior compared to CPST, MAP, and TSP across various soil textures.

Electrochemically Precipitated Struvite, Chemically Precipitated Struvite, Soil Incubation, Soil Texture

Simms, T. , Brye, K. , Roberts, T. and Greenlee, L. (2023) Soil Chemical Property Changes over Time from Struvite Compared to Other Fertilizer-Phosphorus Sources in Multiple Soils. Agricultural Sciences, 14, 1465-1500. doi: 10.4236/as.2023.1410096.