The Effects of Ethephon Application on Suppressing Methane Emission and Stimulating Rice Productivity in a Rice Paddy Soil: A Pot Experiment

Abstract

Ethephon is one of the chemical stimulator of crop growth that is also considered as a structural analogue ofcoenzyme M (CoM), having a promising potential for methanogenic inhibitor. However, the effect ofethephon application on greenhouse gas (GHG) emissions under rice cultivation has not been studied yet. Inthis pot experiment, different levels of ethephon (0, 2.5, 5 and 10 mg L-1) were applied at the presence orabsence of manure compost as an organic amendment to study its effect on GHGs emissions in particular CH4and rice productivity during the cultivation. Application of ethephon effectively suppressed CH4 emissions inparticular the initial periods (ca. 3 weeks) right after the application as compared with control soil during ricecultivation, but did not significantly affect N2O emissions. In addition, the maximum CH4 reduction (82%reduction over control) was found at 10 mg L-1 ethephon application right after its addition for 3 weeks duringrice cultivation. Rice productivity and yield properties were mainly affected by ethephon application,enhancing ripened grains and number of grains per panicle. Soil properties were not influenced by ethephonapplication except for available phosphate, which is probably due to enhanced root growth in rhizospheresoils. Conclusively, ethephon could be a new and pioneering amendment for reducing CH4 emission inparticular at the initial 3 weeks after the application without increasing other GHG emissions and enhancingrice productivity in paddy soils.