Effect of fertilization history on short-term emission of CO₂ and N₂O after the application of different N fertilizers – a laboratory study

Abstract

Increasing organic carbon (OC) stocks in soils reduce atmospheric CO₂, but may also cause enhanced N₂O emissions. The objective of this study was to determine whether there are any differences in N₂O and CO₂ emissions from sandy arable soils with different soil OC and total nitrogen stocks due to the annual application of either farmyard manure (S-FYM) or mineral fertilizer (S-MIN) over 27 years. A laboratory incubation was performed to test the short-term effects of the application of different fertilizers [farmyard manure (FYM), KNO₃ (MIN) and biogas waste (BW)] on N₂O and CO₂ emissions. The CO₂ emission rates indicated that OC availability in the soil was higher after BW application than after FYM application. N₂O emission for 53 days following fertilizer application amounted to 0.01% (MIN), 0.21% (FYM) and 24% (BW) of the total amount of N applied. The high emissions induced by BW were attributed to the combination of a high availability of OC and ammonium in the fermented waste. Fertilization history, which caused higher soil OC stocks in S-FYM, did not influence N₂O emissions. The results suggest that characterization of C and N pools in organic fertilizers is required to assess their impact on N₂O emissions.

Keywords:

• biogas waste
• nitrous oxide
• soil organic matter
• carbon dioxide
• fertilization