Emergy Analysis of Circular Agriculture Mode of "Dairy Cattle-Biogas-Forage"

To study and compare the circular agriculture system of "dairy cattle-biogas-forage"(Mode Ⅰ) with the conventional dairy farm system (Mode Ⅱ) in ecological and economic benefit,emergy analysis method is used.Results show that the net energy yield ratio in Mode Ⅰ was 4.06,lower than that (4.13) in Mode Ⅱ.The emergy sustainable development index was 10.27 in Mode Ⅰ and 9.57 in Mode Ⅱ,suggesting Mode Ⅰ is more capable of sustaining development than Mode Ⅱ.The environmental loading ratio of Mode Ι was 0.11,lower than that (0.12) of Mode Ⅱ,and the emergy waste ratio was 21.72% in Mode Ⅱ but 0 in Mode Ⅰ,suggesting that Mode Ⅰ creates less pressure on the environment than Mode Ⅱ does.The feedback ratio of yielded emergy was 30.63% in Mode Ι but 0 in Mode Ⅱ,suggesting that Mode Ⅰ is higher in self-organizing ability.The net income of ModeⅠwas 1.13 times that of Mode Ⅱ,but the output-input ratio of Mode Ⅰ was 97.64% of Mode Ⅱ.Analysis of the eco-economic benefit of Mode Ⅰ based on the emergy-monetary value showed it was close to the actual economic benefit.Therefore,Mode Ⅰ can be characterized by less environmental pressure,higher self-organizing ability and high sustainable development capability,but it still needs to further optimize its system internal structure and improve its productivity.