An approach of organic amendments: Manure and compost

Organic additions enhance soil structure, increase microbial populations, and supply organic matter and crucial nutrients to agricultural soil. When using organic amendments of animal and/or human origin, it is crucial to consider the potential for contamination with organic and/or inorganic compounds, as well as the risk of spreading potential human illnesses and antibiotic resistance genes. Seven organic agricultural additives were discussed in order to evaluate how their use would impact the aggro-environment. The following amendments were tested for the presence of chemical (metals, aromatics, halogenated hydrocarbons, pesticides, phthalates, and total petroleum hydrocarbons) and biological (Escherichia coli, Salmonella) contaminants: vermicompost, bokashi, municipal solid waste, compost in pellet form, composted cow manure from intensive farms, composted cow manure from organic farms, and composted sheep manure from organic farms.No amendment included any appreciable levels of organic contaminants. Only one variation, the bokashi, contained salmonella. The class 1 integration-linkedintegrate intl1 gene was also shown to be very abundant in bokashi. The composted organic sheep dung included the highest concentrations of total nitrogen, extractable humic acids, and organic matter. Cow dung that has been extensively composted showed the highest levels of microbial activity (potentially mineralizable N) and biomass (microbial biomass C, total bacteria).