Influence of nitrogen sources on grain yield of wheat and net global warming potential

ABSTRACT Nitrous oxide (N2O) emission is mainly associated with aerobic crop culture, which is influenced by nitrogen (N) fertilizer sources, rates, placement methods, and water management systems. The influence of N fertilizers on greenhouse gas (GHG) emission patterns are not well documented in Asian region. The present investigation was undertaken to identify GHG emission patterns, net carbon budget, net global warming potential (GWP) and GHG intensity. N fertilizer from prilled urea (PU), urea super granule (USG) and N-phosphorus (P)-potassium (K) briquette (NPKB) were used and compared with control (no fertilizer). Equal nutrient doses were maintained for all the treatments irrespective of fertilizer sources. Static close chamber technique was used for measuring GHG emission. Depending on treatments, total methane (CH4), nitrous oxide and carbon dioxide (CO2) fluxes were 8.16–10.85, 0.57-0.49-0.59 and 1739–2309 kg ha−1 season−1, respectively and net GWPs varied from −1292 to −2438 kg CO2 eq. ha−1 season−1. Wheat grain yields significantly varied from 3.2 to 3.9 t ha−1 because of N sources and rates. Use of USG for wheat cultivation can increase CO2 removal about 22–88% from the atmosphere along with about 2–14% grain yield and 26–48% soil organic carbon (SOC) sequestration improvements compared to other N sources in Bangladesh.