Evolution of power and mass in specialised agricultural tractors: trend analysis

Le résumé fourni par la source

Specialised narrow-profile tractors for vineyards and orchards constitute a critical and technically distinct segment of the agricultural machinery market, operating under strict dimensional constraints that fundamentally differentiate their design logic from that of conventional field tractors. Despite their agronomic importance, the long-term quantitative evolution of their key technical parameters has remained insufficiently characterised. This study investigates the temporal evolution of engine power, machine mass, and derived tyre-to-soil contact pressure across the European and Italian markets over a twenty-three-year period (2001-2023), using a comprehensive database of more than 5,800 commercial models from 22 producers, regularly updated with the support of Edizioni Informatore Agrario srl (Verona, Italy). Temporal trends and inter-variable dependencies were examined through linear regression and descriptive statistics. Results demonstrate that average engine power increased systematically by approximately 31%, from slightly above 50 kW to 65.5 kW, following a strong linear trend (y = 0.849x, R2 = 0.911) at a mean rate of approximately 0.67 kW per year, while market diversity progressively narrowed toward higher-power configurations. Average machine mass increased concurrently by 36%, driven by the combined effect of powertrain growth, four-wheel drive adoption, mandatory safety structure integration, emission aftertreatment hardware requirements, and expanding hydraulic and electronic system complexity. As tyre dimensions cannot increase proportionally within the inter-row constraints of orchard and vineyard environments, the growth in machine mass translated directly into a consistent rise in average tyre-to-soil contact pressure, which increased from approximately 0.72 bar in 2001 to approximately 0.86 bar in 2023, a cumulative increase of nearly 20%, characterised by a strong linear trend (R2 = 0.919). This value is now closely approaching the experimentally identified critical threshold of approximately 0.90 bar, beyond which macroporosity undergoes severe and functionally significant degradation. The findings reveal a structurally driven and market-wide trajectory toward heavier machines with higher ground contact pressures, representing a growing and quantifiable risk of soil compaction in specialised perennial cropping systems. These results highlight the need to formally integrate ground pressure as a primary criterion in the design, selection, and regulation of specialised tractors, and to develop high-power, low-mass machine architectures capable of reconciling operational performance with the imperative of long-term soil health preservation.

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