Benefit analysis and comprehensive evaluation of rice-fish-duck symbiotic mode1

Three years’study demonstrated that rice-fish-duck symbiotic model can improve rice production by over 10%，meanwhile produce more than 1036．5kg／hm² of fish and 238．9～489．3kg／hm² of adult duck．Total N,P,K and soil organic matter contents of paddy field are increased by 27．9%，44．3%,6．5% and 28．2% respectively．The number of insect pests is decreased ．The symbiotic system largely increased the output and economic benefit．An ecological index (EI)of 0．8155 suggested that it was a high efficient and comprehensive eco-agriculture mode1．