Synergistic effects of biodegradable film mulch and controlled-release fertilizer on economic and environmental performances of sweet maize multi-cropping systems in South China

Sweet maize production in South China faces significant challenges from high weed pressure and inefficient, labor-intensive fertilization practices, which threaten its sustainability. While individual advanced practices like film mulching and controlled-release fertilizers are known to improve crop performance, their interactive effects in a sweet maize multi-cropping system remains poorly understood. Therefore, the objective of this study was to develop a simplified, efficient, and environmentally friendly cultivation practice for continuous sweet maize multi-cropping system in South China. To address this objective, a two-year field experiment was employed to analyze the interactive effects of different mulching practices (conventional plastic film vs. biodegradable film) and fertilization strategies (conventional fertilizers vs. controlled-release fertilizer) on crop yield, economic benefit, soil quality, weed control, and environmental footprints in a sweet maize multi-cropping system in South China. To integrate these multi-dimensional indicators into an overall assessment of system performance, a comprehensive evaluation index (CEI) was developed using the entropy–TOPSIS method. The results showed that the combination of biodegradable film mulching with controlled-release fertilizer achieved the highest fresh ear yield (29.82% higher than CK) and net income (67.33% higher than CK). It also significantly improved soil quality index by 213.76%, weed status index by 258.40% compared to CK. Meanwhile, the yield-scaled and economic-scaled carbon and nitrogen footprints decreased significantly by 20.80%-39.66%, respectively. The CEI score for treatment was 1193.95% higher than CK, ranking as the top-performing and well-balanced practice. Overall, the combination of biodegradable film mulching and controlled-release fertilizer was highly recommended for the sweet maize multi-cropping system in South China. It synergistically enhanced crop productivity, economic profitability and soil quality as well as reduced weed stress and environmental costs. The findings provide a replicable technical reference for achieving sustainable intensification in similar multi-cropping regions globally.