Controlling light quality and intensity can reduce N2O and CO2 emissions of mature aging rice

Abstract

AbstractN2O, CO2, and CH4 are important greenhouse gases (GHGs) in paddy fields, and rice plants play an important role in GHG emissions in paddy fields. However, the relationship between light and rice plant GHG emissions is unclear. In this study, we monitored N2O, CO2, and CH4 emissions of mature aging rice under different light qualities and intensities. The results showed that (i) under natural sunlight, the rice phyllosphere N2O emission rate was 22.94 μg pot–1 h–1, accounting for 60% of the whole rice plant total N2O‐N evaporation loss. The CO2 emission rates from the phyllosphere and the root system were 27.82 mg pot–1 h–1 and 8.02 mg pot–1 h–1, respectively. However, no CH4 net emission effects were observed. (ii) Under a constant LED monocolor light intensity (1600 Lux), red, blue, and white light can inhibit N2O and CO2 emissions from the rice phyllosphere, resulting in lower emissions than yellow light. White light can also inhibit N2O and CO2 emissions from rice roots. (iii) Within the range of 0‒6000 Lux, increases in light intensity can reduce rice phyllosphere CO2 emissions, but such increases also promote N2O emissions from the rice phyllosphere and the roots. In contrast, natural sunlight can promote rice phyllosphere N2O and CO2 emissions and can inhibit root N2O emissions. The measure of light control may be the key to low‐carbon technology for GHG emission reductions in mature paddy ecosystems. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd