ABSTRACT

Livestock production increased towards the end of the 2O century, due to increasing demand in developing countries, production is expected to increase further in Asia ,South America arid Africa, especially Nigeria (FAOSTAT, 2006). Globally, the intensification of agricultural systems increases the environmental impact of food production, as high concentrations of livestock increase the risk that uranic waste nutrients arc used for crop production in excess of crop requirement. Livestock waste contains phosphorus (P) and potassium (K), which have fertilizer values equivalent to those of mineral fertilizers, while its nitrogen (N) conflict has a lower and more variable fertilizer value than that of commercial 1rilizcrs. If appeal at a rate higher than plant uptake, there is a great risk of nutrient leaching and runoff that will pollute surface and groundwater (Burton and Turner, 2003). This will lead to an increased need for water purification to provide safe drinking water supplies. Livestock waste is also harmful to the environment when discharged directly into receiving waters (Rattanarajcbarkul et al., 2001; Steinfeld et al., 2006; Petersen et ah, 2007; and Vu et al., 2007). Negative effects from heavy applications of livestock waste may include salinization in semi-arid 4 regions, toxic concentrations of heavy metals, and decreased soil aeration (Bernal et al., 1992, 1993). Larger production units may result in higher local emissions of odor and ammonia gas from housing and stores. Intensive livestock production may also lead to higher energy use for the transport of livestock wastes to be recycled in crop production elsewhere (Sørensen et al., 2003; Sørensen and Møller, 2006), and the risk of spreading disease among livestock will increase.