Gestione interaziendale dei reflui zootecnici: casi studio in Piemonte

ABSTRACT The application of European Regulations about environmental management and, particularly, those aimed to prevent the water pollution from manure management caused by agriculture nitrates is provoking serious problems to the Italian breeding farms. Nitrogen fertilization has the major influence on the environment health, because it is responsible of the augmentation of the nitrogen concentration in soil and water. Considering that there are many farms without cattle breeding, but with large surfaces, a possible solution to the problem of nitrogen could be a better management of the manure at a local scale. In the last few years the European Government has appointed many laws about this problem; the most important are the Nitrate Directive 91/676/CEE and the Regional DPGR 10/R in Piedmont. The data acquisition for this work has been accomplished by phone and direct interview with farmers, and by local surveys in the farms. In this work we have examined two case studies with these characteristics:  Farm with cattle breeding with land that after new ZVN can find in a nitrogen excess so they must recurrent to assignment or subjection of the manure  Farm with cattle breeding supplied of an anaerobic digestion plant feed with animal manure, part of the crops produced by the farm and those bough from other farms. The analysis performed in both cases followed the same scheme of data acquisition; this in order to obtain information for the description of the farms, of the agronomic and breeding features, manure peculiarity and the nutrient balance calculation. The first case study has been about the analysis of a farm in the municipality of Carmagnola (TO), which has a cattle breeding of 146 Holstein bovines, and a total surface of 43 ha, partially included in nitrate vulnerable zone. Farm lands are cultivated only for animal feeding. The crops are maize, lucerne, meadows and Italian Ryegrass, cultivated in rotation whit maize. The calculation of nutrient balance has shown a good balance between input and output; however manure distribution could be managed in different way maximizing fertilisation efficiency. The second case study has been concentrated on a cooperative of five farms ¿ born to increase the remuneration selling meat directly to consumers. This farm is located in the municipality of Candiolo (TO) and breeds 1174 Holstein bovines. Total surface is 260 ha, partially included in nitrate vulnerable zones. During 2008, the cooperative has supported an important power plant from anaerobic digestion. The power plant is feeded with animal manure and energy crops partially produced by the farm and partially bough from other farms. Digested slurry are employed as fertilizer on farm crops, and the calculation of the nutrient balances has demonstrated that a good equilibrium between input and output. The anaerobic digestion plant has provoked many changes in the management of crops and in the rotation of farms, because the intercrops proportions are considerably grown up; moreover, the cooperative has invested large surfaces with Triticale crop that represents a promising crop for methane production. The evolution of sustainable agriculture must take into account sustainability of the utilization of manure that must be managed as an important resource and not as a waste to be spread.