Effects of irrigation and fertilization on the emission factors and emission intensities of nitrous oxide in alkaline soil

Abstract

Environmental damage attributed to nitrous oxide (N2O) emissions have received widespread attention. Agricultural sources release substantial amounts of N2O into the atmosphere. However, comparative studies on the effects of different irrigation and fertilization methods, namely, drip fertigation (a combination of fertilizing and irrigation), sprinkler fertigation, and traditional furrow irrigation with chemical fertilizer spraying, on N2O emissions in alkaline soil have been limited. Therefore, three-year in situ field observations were conducted to investigate the effect of these three irrigation and fertilization modes on N2O emissions using the static chamber method over the period 2015–2017. There are significant seasonal variations in soil N2O emission fluxes among alkaline soils under different fertilization and irrigation modes, with emissions peaking in July and August, but no significant difference in yearly variations. The N2O emission intensity of drip fertigation soil was 0.20 kg N t-1 year-1, of sprinkler fertigation soil was 0.38 kg N t-1 year-1, respectively, while of furrow irrigation was 0.91 kg N t-1 year-1, respectively. Moisture and temperature of soil were key factors driving the observed nitrous oxide variations. Compared with traditional furrow irrigation, drip and sprinkler fertigation significantly increased potato yield and decreased N2O emissions in alkaline soil, thus satisfying both yield and environmental protection.