Fig. 2: Yield advantages of plastic-mulched crops versus non-mulched systems.

a Forest plots showing percent yield differences analyzed by crop species, mulch thickness, percent film coverage (range 50, 75, and 100% of soil surface covered), mulching type and method, nitrogen fertilization, and soil properties. Ridge–straw mulching: ridges covered with plastic, while furrows covered with crop straw. b Yield responses under varying environmental conditions (altitude, temperature, precipitation, growing season rainfall, geographic region). Regional differences highlight key agricultural areas in China. In both (a) and (b), the number in parentheses beside each error bar represents the sample size of the observed pairs of the two systems (i.e., mulched and non-mulched). The bar length represents the effect size at 95% confidence intervals (CIs). An error bar not overlapping the 0 value on the X-axis (the vertical line) indicates a significant effect between the two systems (P < 0.05). Effect sizes were calculated and analyzed using log response ratios, which were back-transformed and converted to percentage differences. Source data are provided in the Source Data file.