This project aims to systematically evaluate and rank biogas slurry and anaerobic digestate substitution strategies for chemical fertilizers in rice-based cropping systems using a field-based network meta-analysis. Eligible systems will include single-season rice, early-, middle-, and late-season rice, ratoon rice, double rice, rice–wheat rotation, rice–rapeseed rotation, and other rice-dominated rotation systems. The main outcomes will include crop yield, soil nutrient status, soil fertility indicators, nutrient-use efficiency, greenhouse gas emissions, nitrogen and phosphorus losses, heavy metals, antibiotics, and antibiotic resistance genes. Different substitution strategies will be classified into treatment nodes according to replacement ratio and co-amendment type, including pure chemical fertilizer, low-, medium-, high-, and full biogas slurry or digestate substitution, biogas slurry/digestate combined with straw return, biochar, or optimized chemical fertilizer. The study will identify which strategies best balance crop productivity, soil nutrient enhancement, and environmental risk mitigation.
Ze Rose (Thu,) studied this question.