Effects of aerated irrigation on CO2 and N2O emission from protected melon soils under different nitrogen application levels

Abstract

To reveal the effects of coupling nitrogen (N) application and aerated irrigation on soil CO2 and N2O emission, and their relationship with soil temperature and moisture, an experiment was conducted in greenhouse melon fields by using the method of static chamber/gas chromatography to determine the CO2 and N2O emissions of different nitrogen rates under aerated irrigation. There were two irrigation factors (AI: aerated irrigation; CK: conventional irrigation) and three N levels (N1: 0; N2: 150 kg·hm-2, the traditional nitrogen application rate was 2/3; N3: 225 kg·hm-2, traditional nitrogen application rate). The results showed that soil CO2 and N2O emissions in AI treatment were higher than those in CK, but no significant difference was observed between the two irrigation methods. Under the same irrigation method, soil CO2 and N2O emission significantly increased with the increases of N application rate, indicating that N application was the main influencing factor for CO2 and N2O emissions. There were significant positive relationships between soil N2O emissions and soil temperature and water filled pore space (WFPS) under the AI treatment. Soil CO2 emission were positively correlated with soil temperature. When N application reduced to N2 rate under AI treatment, the yield was increased by 6.9% and the greenhouse warming potential was reduced from 9544.82 kg·hm-2 to 9340.72 kg·hm-2. Thus, it is feasible to reduce the amount of N fertilizer under AI treatment to mitigate greenhouse gas emission in agricultural production systems.