Mitigate CH4 emission by suppressing methanogen activity in rice paddy soils using ethylenediaminetetraacetic acid (EDTA)

• Methane emission from rice paddy soils could be suppressed by EDTA application.
• 5.0 ppm EDTA application is probably the most rational dose.
• This dose reduced CH4 emission with sustaining soil properties and rice yield.
• Higher doses were less effective to decrease cumulative CH4 emission.
• In higher EDTA dose, plant growth was also adversely affected.

Methane (CH4) is the second most potent greenhouse gases after carbon dioxide. More than 90% of world rice is cultivated under submerged condition, which facilitates CH4 production in soil. In this pot experiment, different doses of EDTA were applied in rice paddy soils to evaluate their effects on CH4 emission and plant growth during rice cultivation. Application of EDTA at small doses (up to 5.0 ppm) significantly (P < 0.05) suppressed CH4 emission without compromising rice grain yield. Higher doses (10.0 ppm) of EDTA application extended vegetative growth stage of rice plants, which not only reduced ripening percent of rice grains but also increased CH4 emission (even more than control). Therefore, based on this pot experiment data it could be concluded that EDTA application at 5.0 ppm was probably the most rational treatment to mitigate CH4 emission from rice paddy soils.