Last week, Mr. Colom and other farmers were participating in a general strike called across the region, and the tractorada was lending its mechanized mass in support of independence and to denounce the police violence that had followed the vote. When the local farmers’ union put out the call, hundreds of farmers responded — as did the people cheering them on.
“People who are Catalans are very Catalan here,” said Mr. Colom, a mild-mannered father of two, as he steered his tractor onto a dirt-covered square already full of giant machines.
Mr. Colom’s family owns one of the hundreds of farms scattered across the valley, whose center is the town of Vic. It is a major crossroads for two of the highways that cross Catalonia and bring the goods produced by the region to the rest of Spain and to France.
On any given day, trucks carrying milk, meat and livestock waltz through, and Mr. Colom and the others were headed to that junction. Their plan was to park right in the middle.
There was no struggle to get on the highway: earlier, the police had cordoned off a portion of the road, and they gently waved the tractors on. Crowds stood on both sides, chanting and singing to the sound of grallas, a type of flute that sounds like a bagpipe and is a popular instrument here.
It was not the typical farming scene: A documentary filmmaker moved among the tractors, shooting footage. Overhead, a drone buzzed as it filmed the procession. Once the tractors halted at the highway intersection, a massive traffic jam of trucks ensued. Unable to deliver their goods, a few of the drivers napped in the cabs of their trucks.
The center of the Catalan independence movement is Barcelona, a cosmopolitan metropolis, where urbanites are at the core of the demonstrations — which is why the tractors are a seemingly unlikely symbol. Some tractors cost over 100,000 euros, around $117,000, and feature computers, joysticks, control panels with LED lights and air-conditioned cabins. Others are secondhand clunkers.
Farmers in the rest of Spain and Europe have for decades used tractors in protests about the cost of gas or the wholesale price of produce. But they have rarely attracted as much attention and popular support as they have in recent weeks in Catalonia. And even as the protest schedule is busy, so is the schedule on the farm.
“The cows dictate a rigorous schedule,” said Martin Serralonga, 50 as he drove on the highway at the speed of a snail. “For many people with livestock, this is the first time they’ve come out,” he said, adding that his son, as did about half of the crowd, had to rush home early afternoon to do the milking.
With some pride in his voice he added, “The politicians needed us to come out, like when we help fight wildfires, because we know the ground the best.”
The sudden attention on the farmers comes as many young people are leaving the fields for city life. Jordi Prat, 42, grew up in a family that still trades in livestock, but he opted to study in Barcelona and then become a dentist in Vic. Yet, when the call to protest went out to local farmers, he jumped in the driving seat of his family’s tractor.
When he was younger, he said, he spent entire days perched in the seat, working in the fields. Sometimes, when he climbed down in the evening, his legs were wobbly from exhaustion.
“We are the most hard-working country there is in Spain,” he said. “Here, people wake up to work, not to play the guitar.”
For all their symbolic force, the farmers themselves seemed uncertain about what independence would bring, or if it was even likely to happen as soon as regional politicians predicted.
They preferred to talk about their ancestors’ struggle, referred to in the Catalan anthem that crowds have been singing across the region. “Els Segadors” speaks of a 17th-century revolt by peasants and others against Spanish rule.
“Like in the anthem, we will break the chains with the sickles,” said Miquel Colom, 44, the older brother of Jordi and Imma.
As night fell on the valley and tractors headed home, Miquel was cleaning up the cement barn floor at the Colom family farm under floodlights as a herd of about 60 cows rested in their stalls.
“These days we haven’t worked much,” he said, looking up from the evening routine, dressed in a blue overall. “Everyone is glued to their smartphones, sending WhatsApps.”