Livestock-biogas-fruit systems in South China

Fruit farming and animal husbandry have existed for a long time in Meixian, Guangdong, South China. However, Meixian suffers from shortages of rural energy and organic fertilizer and from environmental pollution. A new eco-agricultural system, the livestock-biogas-fruit system, has been designed successfully in this region by adding biogas production to fight these problems. A study which was conducted in seven households (family farms) in this region in 1994 showed that the three major components of this system functioned in harmony for the mutual benefit of these farmers and their environment. Pomelo (Citrus grandis) farming was the most profitable component of the system. Pomelo litterfall and pig dung were fed into the biogas digester underneath the pigsty. The di domestic fuel and sludge as fertilizer. Chickens were raised in the orchard where they fed on weeds and pests, and deposited excreta as fertilizer. Recycling of wastes improved soil texture, and thereby decreased input of chemical fertilizers. This system helped natural enemies function well in these case studies, and therefore decreased the application of pesticides. Serving as a key link between fruit farming and animal husbandry, biogas production alleviated the scarcity of rural energy in Meixian. (C) 1997 Elsevier Science B.V.