Greenhouse Gas Emissions from Flood-Irrigated Rice as Affected by Phosphorus Fertilizer Source

Research into alternative phosphorus (P) fertilizer sources that may be able to supplement P resources is necessary. Struvite (MgNH 4 PO 4 · 6H 2 O) can be made by removing excess nutrients from waste sources and may reduce greenhouse gas (GHG) emissions from cropping systems. This study sought to quantify GHG [i.e., methane (CH 4 ), nitrous oxide (N 2 O), and carbon dioxide (CO 2 )] fluxes, season-long emissions, and net GHG emissions from chemically precipitated struvite (CPST) and synthetic and real-wastewater-derived electrochemically precipitated struvite (ECST) compared to monoammonium phosphate (MAP) and an unamended control (UC) from flood-irrigated rice ( Oryza sativa ) grown in P-deficient, silt loam soil in a greenhouse. Gas samples were collected weekly over a 140-day period in 2022. Methane and CO 2 emissions differed ( p < 0.05) among P fertilizer sources, while N 2 O emissions were similar among all treatments. Methane, CO 2 , and N 2 O emissions from MAP-fertilized rice were the greatest (98.7, 20,960, and 0.44 kg ha −1 season −1 , respectively), but they were similar to those of CH 4 and CO 2 for CPST and those of N 2 O for all other P fertilizer sources. Season-long CH 4 , CO 2 , and N 2 O emissions and net GHG emissions did not differ between ECST materials. This study’s results emphasized the potential that wastewater-recovered struvite has to reduce GHG emissions in rice production systems.