Effects of Paddy Field Environmental Factors on Greenhouse Gas Emissions Under Intermittent Irrigation

Greenhouse gas emissions are closely related to field environmental factors. In this paper, the intermittent irrigation model was used to study the environmental impact mechanism of greenhouse gases (CH ₄ , CO ₂ and N ₂ O) emission in rice fields through an open-circuit vorticity system. It was found that the change trends of rice field temperature, soil temperature and rice canopy temperature were basically the same, and they all reached the maximum at the end of tillering. The dynamic changes of gross primary production(GPP) and net ecosystem production(NEP) are consistent, and the total accumulation of GPP and NEP in the whole growth period is 850.51 g C/m2 and 294.36 g C/m ² , respectively. GPP and NEP are related to photosynthetically active radiation (PAR) has a linear positive correlation and a quadratic function relationship with saturated vapor pressure difference (VPD). Methane emission reached its peak at tillering stage, with daily emission of 0.02 ~ 1.19 g/m ² /d and cumulative emission of 27.05 g/m ² during growth period. CH4 emission has a linear positive correlation with temperature and VPD changes, which explain the variation of CH ₄ by 15.12%~17.37% and 10.14% respectively.