Effects of silicate application on CH4 and N2O emissions and global warming potentials in paddy soil under enhanced UV‐B radiation

Abstract

AbstractEnhanced ultraviolet‐B (UV‐B) radiation is induced by the depletion of the stratospheric ozone layer. Silicate is beneficial to rice growth and can increase the resistance of rice plant to UV‐B radiation, but so far few reports have been available on whether silicate application can reduce CH4 and N2O emissions from paddy soils under enhanced UV‐B radiation. A field experiment was conducted to investigate the effects of silicate application on CH4 and N2O emissions and global warming potentials (GWPs) under enhanced UV‐B radiation in a paddy soil. The experiment with rice was designed with two UV‐B radiation levels, that is, ambient UV‐B (A, ambient) and enhanced UV‐B radiation (E, enhanced by 20%); and two silicate application levels, that is, control (Si0, 0 kg SiO2·ha−1) and silicate application (Si1, 200 kg SiO2·ha−1). CH4 and N2O fluxes were determined by closed chamber method at one‐week interval during rice growth period. The results show that, compared with ambient UV‐B radiation, enhanced UV‐B radiation clearly decreased the dry matter weights of shoot, root, and whole plant by 13.12%, 53.31%, and 25.85%, respectively, in the treatment without silicate application, and by 1.47%, 34.49%, and 11.12%, respectively, in the treatment with silicate application. Enhanced UV‐B radiation significantly increased the flux and cumulative emission of N2O and stimulated the GWPs of CH4 and N2O. Silicate application significantly reduced flux and cumulative emission of CH4, promoted the flux and cumulative emission of N2O, and reduced the GWPs of CH4 and N2O. This study suggests that silicate application can reduce the contribution of enhanced UV‐B radiation to global warming potentials.