Waste Management Issues, including Recovery, and Sustainable Food and Agriculture

The use of different agricultural or industrial wastes is an important component of sustainable agriculture in order to close nutrient cycles on a global, regional and local scale. Farmyard manure or slurry are established as fertilizers in agricultural or horticultural production and substitute mineral fertilizers. Due to the lower nutrient use efficiency compared with mineral fertilizers, especially in the case of nitrogen substantial losses to the environment may occur and cause ground water contamination or eutrophication. Therefore all technical means to reduce such losses on the local and regional level have to be considered. Feedlots are of special concern in this context because there stocking rates are extremely high and only a limited area of arable land or pasture is available for the use of organic fertilizers. In such cases regional solutions have to be encouraged. The use of wastes from food as well as paper production is another option to close nutrient cycles but special care has to be taken in order not to transfer heavy metals or infectious material in the food chain. For those reasons the application of either agricultural or industrial wastes is in most countries strictly regulated by legislation.