Nitrous oxide emissions after struvite application in relation to soil P status

Purpose Although struvite (MgNH4PO4 center dot 6H(2)O) is mostly considered to be a novel phosphorus (P) fertiliser, it does contain a significant amount of nitrogen (N). Yet, relatively little is known about the soil N dynamics in struvite-amended soils. Here, we focus on how struvite application impacts emissions of the greenhouse gas nitrous oxide (N2O), in relation to soil P status. Methods We conducted a 54-day greenhouse pot experiment on two similar soils with different P status (low-P soil; high-P soil) seeded with Lolium perenne L. We applied seven fertiliser treatments (Control; Struvite granules; Struvite powder; Urea; Triple superphosphate (TSP); TSP + Struvite granule; TSP + Urea). Except for the unfertilised Control and the TSP treatments, N application rate was 150 kg N center dot ha(-1). Nitrous oxide (N2O) fluxes, aboveground yield, plant N and P uptake and readily plant-available soil N and P contents were measured. Results In the low-P soil, none of the fertiliser treatments induced a significant increase in N2O emission compared to the control. In the high-P soil, struvite application resulted in lower emissions than urea application, statistically not different from the control treatment. Struvite powder significantly increased both plant N and P uptake compared to granular struvite and the resulting yield was similar to conventional fertilisation (TSP and Urea). Any struvite application also resulted in lower readily plant-available soil nitrate contents than urea. Conclusion Our results suggest that struvite fertilisation can reduce the risk of gaseous N losses without compromising agronomic performance. Pulverizing struvite granules further promotes its dissolution, which could be useful for crops with early nutrient needs.

Automated summary

This study investigated the impact of struvite fertilizer on soil nitrogen dynamics and nitrous oxide (N2O) emissions. The results showed that struvite application did not significantly increase N2O emissions in low-phosphorus soil. In high-phosphorus soil, struvite application resulted in lower N2O emissions compared to urea, with no significant difference from the control treatment. Furthermore, struvite powder increased plant nitrogen and phosphorus uptake and yielded similar results to traditional fertilization. In conclusion, struvite application can reduce the risk of nitrogen loss without compromising agronomic performance.