title: [Emergy value evaluation on rice-duck organic farming mode].
abstract: Employing emergy value evaluation method, this paper compared the ecological and economic benefits of rice-duck organic farming system (mode I) and conventional rice-wheat rotation system (mode II) in Shanghai suburb. The results showed that mode I had better emergy benefits, higher self-organizing ability and sustainability, and higher product safety. The net emergy yield ratio (EYR), feedback ratio of yield emergy (FYE), and emergy sustainable index (ESI) of mode I were respectively 1.57, 14.1, and 8.71 times as much as those of mode II, and the emergy index of product safety (EIPS) was 0 in mode I but -0.66 in mode II. The emergy investment ratio (EIR) and environmental loading ratio (ELR) of mode I were 40.1% and 18.3% of mode II, respectively, suggesting that mode I had less environmental pressure than mode II. Mode I had lower economic benefits than mode II. The economic output, gross income, and net income of mode I were 15.7%, 9.6%, and 29.6% less than those of mode II , respectively. As for Em dollars, the output, gross income, and net income of mode I were respectively 50%, 102.6%, and 136.4% higher than those of mode II. With the system optimization and the development of organic food market, mode I had the potential to improve its economic benefits.
authors.affiliation: School of Life Science, Nanjing University, Nanjing 210093, China. xi158@yahoo.com.cn
authors.forename: Yunguan
authors.initials: Y
authors.lastname: Xi
authors.forename: Pei
authors.initials: P
authors.lastname: Qin
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources; D004372:Ducks / Q000254:growth & development*; D017753:Ecosystem; D018803:Models, Economic; D012275:Oryza / Q000254:growth & development*; D014908:Triticum / Q000254:growth & development*