Nitrous oxide emissions after application of cattle-manure-based pellet of different pH levels to an Andosol upland field

• Published in: Nutrient cycling in agroecosystems 2023-05, Vol.126 (1), p.35-49
• Main Authors: Yamamoto, Akinori, Arai, Kana, Sudo, Shigeto, Takemoto, Minoru, Nakamura, Haruka
• Format: Article
• Language: English
• Subjects: Agriculture; Biomedical and Life Sciences; Cattle; Denitrification; Emission; Emissions; Fertilization; Fertilizers; Life Sciences; Manures; Microorganisms; Mineral fertilizers; Nitrification; Nitrous oxide; Pellets; pH effects; Soils; Statistical analysis
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-023-10271-3

The pH of manure pellet fertilizer can affect the nitrous oxide (N 2 O) emission from soil, although its effectiveness and the relative mechanisms are not well understood. This study aims to quantify the effect of cattle-manure-based pellet pH on N 2 O emissions from an Andosol field. The field experiment consisted of four treatments: chemical (mineral) fertilizer (CF), cattle-manure-based pellet fertilizer of pH 5.6 (OP), cattle-manure-based pellet fertilizer of pH 7.1 (NP), and cattle-manure-based pellet fertilizer of pH 10.1 (AP). Cumulative N 2 O emission over the 365 days in the OP and NP treatments was 59.4% and 49.3% lower than that in the AP treatment, respectively, but the cumulative N 2 O emissions were statistically significant only between the OP and AP treatments. Moreover, cumulative N 2 O emission in the pellet fertilizer treatments during the peak period after fertilization in the autumn and spring cropping seasons (total 70 days) increased with increasing pellet pH. In the pellet fertilizer treatments, soil nitrification potential, soil N 2 O production rate, and total denitrification rate of soil also clearly increased with the increase of pellet pH. Therefore, slightly acidic pellet pH (OP treatment) may have inhibited the microbial N 2 O production processes in comparison to the neutral pellet pH (NP treatment), but alkaline pellet pH (AP treatment) could have stimulated the microbial N 2 O production processes than the neutral pellet pH. These results suggested that increased N 2 O emission with an increase in pellet pH may be attributed to a change in the N 2 O production rate via nitrification and denitrification.