Agriculture provides food to humans and feed to livestock; livestock provide biomass energy for biogas; manure produced by cattle also provides fertilizer for agriculture; organic waste produced by citizens is used as biogas and fertilizer (see Figure 4.2.1). This web-like relationship is important to both energy and material flows. Here, four self-sufficiency rates are considered simultaneously: food, fertilizer, feed and energy for the city of Furano in northern Japan.