What does a modern combine harvester and a Diplodocus have in common? One answer, it seems, may be their big footprints on the soil. A new study led by researchers from Sweden and Switzerland has found that the weight of farming machinery today is approaching that of the largest animals to have ever roamed the Earth – the sauropods.
Depicted as the giant, friendly “veggiesaurus” in the movie Jurassic Park, sauropods were the biggest of the dinosaurs. The heaviest were thought to weigh in at around 60 tonnes – similar to the weight of a fully laden combine harvester. Tractors and other machinery used on farms have grown enormously heavier over the past 60 years as intensive, large-scale agriculture has become widespread. A combine harvester is almost ten times heavier today than it was in the 1960s.
The weight of animals or machines matters because soils can only withstand so much pressure before they become chronically compacted. They may not look it, but soils are ecosystems containing fragile structures – pores and pathways which allow air to circulate and water to reach plant roots and other organisms. Tyres, animal hooves and human feet all apply pressure, squashing the pores, not just at the surface but deeper down too.