This paper will describe the details of the nutrient flow by a comparative study on bio- gas slurry versus chicken manure to culture fish. The dominant fish species stocked were Tilapia Oreochromis nilotica, silver carp Hypophthalmichthys molitrix and bighead carp Aristichthys nobilis. The secondary species stocked were small amount of common carp Cyprinus carpio, crucian carp Carassius auratus, bream Megalobrama amblycephala and grass carp Ctenopharyngodon idella. The results indicated that the net fish yield reached 12 t/ha by slurry whereas 3.4 t/ha by chicken manure. The economic return of the former was 2.5 times the latter. The nutrient flow analysis will explain the reason why the differences between the two. It proves that fish farming by slurry is an effective approach to raise the utilization rate of waste materials and to promote the development of ecological agriculture.

Mr. Kangmin Li (retired in 1995) graduated as an engineer from the Military College in early 1950s and worked at the General Staff Headquarters (GSH) of the People's Liberation Army (PLA) for 30 years. He finished his post graduate from the Luoyang Foreign Language Institute. From 1983 to 1986, he served as the Deputy Director of Asian Pacific Regional Research & Training Center for Integrated Fish Farming, responsible for International Training Course of Integrated Fish Farming. He has conducted researches on integrated bio-systems (rice fish culture), blue-green algae control, extraction of phycocyanin from Microcystis aeruginosa and surface aquaponics, etc. From 1987 Mr. Li was engaged in researches on IBS (esp. rice fish culture), blue-green algae control in Lake Taihu, extracting Phycocyanin from Microcystis aeruginosa, surface aquaponics and so on. He has written more than 20 papers, most of which were published in overseas.  Mr. Li was a visiting researcher of Chinese National Rice Research Institute (1996-1997) and a ZERI Resources Personnel (1997 to 1999).

Mr. Kangmin Li is currently an Associate Professor (Senior Researcher) of Freshwater Fisheries Research Center (since 1989) and also the Deputy Director of Cell Bio Technology Research Institute.

Ms. Wang Qiuhua
Associate Researcher and Senior Engineer, Nanjing Environmental Protection Research Institute. P.R. China

Ms. Wang Qiuhua is a graduate from Nanjing University. During 1968-1984, she was engaged in research work of nuclear tests as an assistant researcher in 21st Proving Ground under National Defense Science Commission. After 1984 engaged in rural ecological environment protection, rational utilization of agricultural produce and wastes, ecological agriculture, organic farming, with more than 40 papers published and involvement in several international cooperation projects. Earlier works include : 
(a) study on the benign cycle and optimization model of rural ecological economy that received the Silver Award of Science and Technology Progress of NPA. 
(b) involvement in Hehun Village Ecological Demonstration which was named as one of 500 Best Global Environment in 1990 by UNEP. 
(c) services as the technical advisor (1994-1999) of 11 Counties in East China Group of 51 Ecological Counties Project. The paper "Study on ecological agriculture models and techniques in high yielding grain districts in the middle and lower reaches of the Yangtze River" is under review. 
(d) involvement in the "Study on Environment Quality Analysis of Main Natural Resources in Rural Areas" on quantity, distribution, characteristics of straw and stalk, animal wastes and human wastes, status quo as resources and existing problems. It introduced several approaches and techniques of rational utilization and development in depth of bioresources.

Ms Wang is currently developing a series of natural products such as bio-active fertilizer, feed active agents, plant protection liquid, fruit and vegetable preserving agents, which are beneficial to the production increase of crops, fowl and livestock (ready for commercialization).