The regression tests for the funnel plot asymmetry of CH4 emissions, N2O emissions, GWP, rice yield, and the GHGI were z = −1.33, −0.47, −0.60, and − 1.87, respectively, and p > 0.05. Publication biases were not detected. The Rosenthal's fail-safe numbers (N) were 8485, 7078, 366, 4617, and 1978, respectively. As they were greater than 5n + 10 (n = 70, 41, 39, 37, and 37, respectively), the results for these indices were likely not affected by non-significant, unpublished studies. Overall, the CH
