Slurry acidification outperformed injection as an ammonia emission-reducing technique in boreal grass cultivation

Abstract

Ammonia (NH3) constitutes the single largest loss of manure nitrogen (N), making measures targeted at reducing its emissions meaningful for the environment and the overall efficiency of manure N use. In this study, the performance of two emission-reducing techniques, acidification and injection, were studied in a field experiment with grass ley over two growing seasons. Emissions of NH3, crop growth, and N use efficiency were determined from plots fertilized with cattle slurry either band spread, injected or band spread after acidification. The approximate cumulative NH3 losses from the plots with band-spread untreated slurry amounted to about 22 kg NH3-N ha−1 over the observation periods in 2017 and 10 kg NH3-N ha−1 in 2018. The injection and acidification reduced the estimated cumulative NH3 emissions by 43 and 95% respectively in 2018, and both by 97% in 2017. In 2017, the emission-reducing techniques had no impacts on crop growth, but in 2018, acidification increased dry matter yield by 29% and apparent N recovery by 65% compared with band-spread untreated slurry. According to the current results, acidification consistently produced the lowest NH3 emissions and a discernible positive yield effect. It can therefore be recommended instead of injection for reducing NH3 emissions in boreal grass cultivation.

Long‐term changes in soil phosphorus in response to fertilizer application and negative phosphorus balance under grass rotation in mineral soils in Nordic conditions

“…Hence, a N deficiency, rather than a lack of P, caused the yield decrease observed in the PS treatment. Moreover, a loss because of ammonia volatilization in the surface application of slurry reduced N utilization in the PS treatment compared with mineral N (Keskinen et al., 2022).…”

Effect of slurry application techniques on nitrous oxide emission from temperate grassland under varying soil and climatic conditions

“…Slurry acidification is an efficient technique to reduce NH 3 volatilization (Keskinen et al, 2022); however, its effect on N 2 O emission is not consensual as enhancing effects (Gómez‐Muñoz et al, 2016), no effects (Malique et al, 2021), and mitigating effects (Owusu‐Twum et al, 2017; Park et al, 2018) have been observed. Furthermore, the results of slurry acidification on soil microbial structure and function, Mineral Fertilizer Replacement Value (MFRV) and herbage yields, particularly in permanent grasslands, are unclear due to limited research (Fangueiro et al, 2015).…”