Bridging the gap between reliable data collection and the environmental impact for mechanised field operations

Mechanisation is related to an important proportion of the environmental impacts associated with agriculture, mainly due to engine fuel consumption and exhaust gas emissions, and materials production, use and disposal. Despite standardised and extensively accepted methods for environmental impact assessment have been developed, their application to mechanical field operations is still limited. In absence of reliable data, the reductions in environmental impact that are achievable cannot be easily evaluated by studying machinery already available on the market and more suitable machinery or by selecting the proper coupling between the implement and the tractor. This study carries out a comparative Life cycle assessment (LCA) of a rotary harrowing operation using different data sources. Data was gathered from: (i) Ecoinvent database, (ii) ENVIAM, a tool developed to support the completion of inventories for agricultural machinery varying the local pedo-climatic, operating and mechanical features, and (iii) primary data directly collected during experimental tests with CAN-bus, GPS and exhaust gases analyser. The analysis showed that using database average data, the resulting environmental load is not always reliable and, in this particular study, it consistently overestimated most outcomes. Moreover, by processing primary data collected using modern technology, the operation could be split in different working phases (effective work, turns, stationary-idling). Thus, specific mechanical features were quantified and this permitted the environmental impact to be evaluated with more detail.