A Review of piggery manure management: generally, across western, Asian and African countries

Abstract

The aim of this paper was to review the piggery waste management aspects in several countries of the world. Intensive livestock production produces significant quantities of waste that must be managed to protect water, air, and crop quality. The high demand of modern animal production has been influenced by the rapid growing populations as a result of rapid economic growth and increase in community living standards which is associated with the accelerated generation rate of solid waste causing a seriousworldwide challenge. Piggery waste is said to be one of the most important causative agents of environmental pollution in most parts of the world. A growing pig population is unavoidable because it is a convenient source of protein to the growing human population and at the same time this means increasing piggery waste. Animal manure can provide nutrients for crops and fish production and input for biogas production, but if not managed, then this can also have a negative impact on the environment. Nevertheless, there are few countries who are considering legislation in relation to manure management.IntroductionLivestock is very important in contributing to the sustainability of agricultural systems as an integral part of traditional farming system by using crop residues and other feeds which are not utilized by humans and converting them into milk and meat (Martinez et al, 2009). Manure from different livestock species can replace a good amount of mineral fertilizer as plant nutrients, provided it isrecognized and used accordingly as a valuable resource (Bouwman and Booij, 1998; Chau, 1998). However, at the same time animal manure can be a source of air pollution as well as a threat to aquifers and surface water (Burton and Turner, 2003). Commercialpig production is rapidly growing in most parts of the world with a trend towards larger production units utilizing modern production technologies such as modern housing, improved feeding and better breeding methods. This type of trends influences the riskof water pollution, air pollution as well as soil pollution (Gerber et al. 2005)Pig Production and the FuturePig meat is the most consumed meat in the world (Gentry et al. 2002). It was noted that pork is the highest consumed protein with a total of 110million metric tonnes followed by chicken with 104 million metric tonnes and beef with only 67 million metric tonnes per year (McGlone, 2013). China produced 50 million metric tonnes which is almost half of the world production in 2011(Table 1). Germanywas