The environmental impact of buffalo manure in areas specialized in mozzarella production, southern Italy.

Buffalo livestock plays a central role in the regional economy in some areas of southern Italy, through the production of mozzarella cheese. With about 250,000 heads per utilizable agricultural area (equal to 107,400 ha), livestock husbandry is intensive. An important issue with regard to high animal density is manure management, an activity determined by cost optimization and the laws governing environmental sustainability. According to community, national and international rules (European Directive 91/676, Italian rules 152/99 and 258/00), nitrate leakage is considered a pollution indicator related to breeding activities and must be kept within limits. Simulation studies were carried out in the Italian province of Caserta to evaluate the impact of leakage on groundwater. Manure was also collected from 35 livestock farms and the nitrogen content measured in the laboratory. The results showed an average content of 2 kg/m3 of nitrogen, corresponding to 50 kg per animal and year, while the nitrate concentrations in the groundwater were found to be lower than those predicted by simulation. The nitrogen content found in buffalo manure <60% of the standard content produced by the bovine species (on average 83 kg nitrogen per adult animal per year). The fact that the bovine species is used as the standard reference for legislation on nitrogen production explains the inconsistency observed between the impact of buffalo livestock on the environment predicted by simulation and the nitrate concentration measured in the groundwater. Although it would be out of line with current regulations, it would theoretically be possible to increase the buffalo load on the territory without environmentally negative effects. Therefore, in this context, the common referral points, i.e. the American Midwest Point Service and others usually consulted for the assessment of livestock impact in terms of nutritional excretion and the risk of pollution for the environment, should be revisited.