A high-quality farm tractor is taller than an African elephant. And full of grain, the combined harvester weighs 36 tons — the equivalent of a small flock of pachyderm. As these mammals cut down fields, their excessive height can gradually erode the soil and make it difficult for plant roots to grow. Such results, a new study suggests, could reduce yields on all 20% of the world’s plants in decades to come.”Heavy machinery is something we should not ignore,” said Rattan Lal, a soil scientist at Ohio State University, Columbus. “It can really cause damage.”
Extra weight comes at a cost
Tractors have been growing since the 1960s, and larger ones now weigh 10 times more than they did at the time. That survival is more than any other sauropod dinosaur, the largest living creature ever to walk the earth. While the size of the machines makes them more efficient, all that extra weight comes at a cost.To find out how agricultural vehicles have changed — and how they may affect the soil — Thomas Keller of the Swedish University of Agricultural Sciences and Dani Or of the Desert Research Institute compiled industry data published back in 1958. Then, they measure the energy used. with tires in the ground at various depths.
In mechanized farming, congestion has long occurred in the topsoil, in layers less than 50 inches [50 cm] deep. On many farms, the topsoil is plowed or plowed each season to prepare the planting area, making such pressure less likely to matter. The problem is now deepened, say researchers, because overcrowding of less than 50 inches [50 cm] often crosses safe boundaries.This compaction can break down small gaps between soil particles, allowing less water and air to reach deeper ground. Overall, these changes can reduce crop yields by 10% to 20%. And the effects can be long-lasting: It could take decades for worms and other organisms to loosen the deep soil.
It is not just a gathering of harvest workers. Other farm implements, which are used for farming and fertilizing, are also becoming more and more difficult, as are the vehicles used for logging. About 20 percent of the world’s agricultural land is at risk of low yields resulting from deep soil compaction, reports the authors today in Proceedings of the National Academy of Sciences. These places, such as the savanna of Brazil and southeastern Australia, have a dangerous soil and heavy machinery — and are the bread baskets in the world.
New research suggests
Thomas Way, an agricultural engineer at the U.S. Department of Agriculture, says there are ways to reduce soil compaction. Another is not driving in the fields when it is wet, which puts the soil in danger. And in dry weather, GPS can help farmers drive the same routes each time to reduce the total area under pressure.New research also suggests what paper writers call “prehistoric paradoxes.” If modern farming equipment puts pressure on crop production to such an extent, what happens when sauropod dinosaurs roam the Earth? Perhaps they are clinging to old roads, researchers speculating, or perhaps diving into coastal waters. Whatever the answer, it is clear that modern farm machinery must be built with an eye toward the soil; otherwise they risk taking the dinosaur path.
Source Journal Reference:Erik Stokstad, Big tractors, now heavier than many dinosaurs, can damage deep soil, Science (2022) News, doi: 10.1126/science.add0336, https://www.science.org/content/article/big-tractors-now-heavier-many-dinosaurs-can-damage-deep-soil
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