| Abstrakt: |
Integrated rice–crayfish systems are expanding rapidly and are the most widely applied planting–breeding modes in Jianghan Plain in China. We conducted nutrient use efficiency, economic, and emergy analysis of three rice production modes, namely, rice monoculture (RM), rice–crayfish rotation (RCR), and rice–crayfish coculture (RCC), in Jingzhou City, which is located in the Jianghan Plain. Compared with RM mode, rice–crayfish systems using the RCR and RCC modes increased rice yield by 5–7%, showed more than 8% higher chemical nutrient use efficiency, and increased the value-to-cost ratio from 1.5-fold to 2.7-fold and the benefit–cost ratio from 2.5-fold to 3.8-fold, while decreasing irrigation water consumption and land occupation by 31% and 82–86%, respectively. RCC resulted in 10% higher crayfish yield, 12% higher phosphorus use efficiency, and 38% higher feed use efficiency than RCR. However, compared with RM, rice–crayfish systems decreased renewable fraction by 10–14%, emergy yield ratio by 9%, and emergy sustainability index by 23–26%, and they increased environmental loading ratio to 18–23%. Labor and service, fertilizer utilization, and machine and tools play important roles in these negative environmental effects. Scenario analysis showed that the rice–crayfish systems increased sustainability index by 38–45%. The technical training of new planting–breeding technology should be adopted by farmers for the efficient use of fertilizers and improvement of food yield. This study suggests that rice‑crayfish systems are not a panacea to sustain cleaner food production. [ABSTRACT FROM AUTHOR] |
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