Energy, carbon and water footprints on agricultural machinery

Abstract

Agricultural machinery is crucial to agriculture because it enables field activities and production in large scale. Through mechanisation, agriculture requires inputs such as fuel and indirectly demands materials. Its impact can be assessed through energy, water and carbon footprints. Some studies have updated indices for agricultural machinery, showing different results from those of the 1970s and 1980s. This study presents environmental indices based on energy, carbon and water footprints for the life cycle of six types of agricultural machinery. The machines studied were tractors, sugarcane harvesters, coffee harvesters, sprayers, planters and combiners. Inputs used directly (assembly phase) and for the maintenance phase have been taken into account. The total energy, carbon and water footprints were by multiplying the material flows by their respective energy embodiments, consumed water and carbon footprints indices. Carbon steel accounted for the highest share (30–70%) of energy demand, 45–79% of carbon footprint and 19–59% of water footprint. However, the coffee harvester was an exception since it used nylon making it the machinery with the largest water footprint. Repair and maintenance accounted for a smaller share of all footprints, except for the sugarcane harvester. The water footprint was from 21 to 55 m³ for tractors and between 35 and 391 m3 for other machines. Energy demand varied between 259 and 685 GJ to tractors and between 400 and 3500 GJ for other machines. The carbon footprint varied between 11 and 30 t CO2e for tractors and between 27 and 176 tonne [CO2e] for other machines.