The effect of integrated rice–frog ecosystem on rice morphological traits and methane emission from paddy fields

Integrated Rice–frog Ecosystem (IRFE) has the potential to reduce methane (CH4) emission and maintain yields from paddy fields. However, the quantitative relationship between rice morphological traits and CH4 emission remains to be explored. In this study, a 2-year field experiment was conducted to evaluate the effect of IRFE on rice morphological traits and CH4 emission from paddy fields and the ecological mechanisms. This study was conducted to analyze twelve aboveground and eight underground rice morphological traits, rice yields, and CH4 flux and emission from the paddy fields with six frog densities (0, 3750, 7500, 15,000, 30,000, and 60,000 frogs ha−1). The results showed that IRFE reduced CH4 emission by 24.70%–41.75% and 21.68%–51.21% in the 2018 and 2019 rice growth seasons, respectively. Moreover, CH4 emission decreased with the increase of frogs. Frogs also increased the diameter, biomass, and volume of rice roots, thus promoting rice growth. Root biomass, thousand-grain weight, and harvest index were also closely related to the yield. Root porosity and oxygen secretion capacity were negatively correlated with CH4 flux. Frogs increased root porosity and oxygen secretion, thereby reducing CH4 emission. The present study demonstrated that reducing CH4 emission and improving rice yields could be simultaneously achieved by altering rice morphological traits in IRFE. [Display omitted] •Frogs can reduce CH4 emission by 21.68%–51.21% in rice seasons.•Rice morphological traits are closely related to CH4 emission.•Frogs can increase soil nutrients, thus changing the root morphology.•Root porosity contributes greatly to the CH4 emission reduction.•The IRFE can reduce CH4 emission and maintain yields.