Nitrous oxide emission from tea soil under different fertilizer managements in Japan

• Seasonal variation of N2O emission was driven by soil temperature.
• Chemical fertilizer emitted more N2O than did organic fertilizer.
• The ratios of N2O from the soil on row and under canopy were 47.9% and 52.1%.

A field experiment was conducted to assess N2O emissions in response to different fertilizer types and amounts in a heavily fertilized tea field in Japan. Four treatments were implemented: CONT: no fertilizer, CONV: conventional fertilization, 1/2CONV, and CHEM: chemical fertilization. Gas samples were collected 5–8 times after every fertilizer application using the closed chamber method. The results revealed high seasonal variation in N2O emissions driven by soil temperature rather than the fertilizer application time. The soil temperature at a depth of 0–10 cm was significantly correlated with N2O emission (P < 0.01). The highest cumulative N2O emission (73.2 kg N ha− 1 yr− 1) was observed in the CHEM treatment, followed by the CONV treatment (65.0 kg N ha− 1 yr− 1), the 1/2CONV treatment (18.6 kg N ha− 1 yr− 1) and the CONT treatment (1.8 kg N ha− 1 yr− 1). The highest N2O emission factor (7.9%) was found in the CHEM treatment, followed by the CONV treatment (7.0%) and the 1/2CONV treatment (3.7%). There were spatial differences in the soil characteristics across the tea field. Accurate estimates of the ratios of N2O emitted from the four treatments during the two crop seasons were 47.9% and 52.1% from the soil on the rows (108.6 kg N ha− 1) and under the canopies (118.3 kg N ha− 1), respectively.