Slow-moving convoys of some 2,700 tractors blocked roads in Brussels on Friday as farmers from the Flanders region protested at moves to cut nitrogen emissions.
Central thoroughfares were closed as the agricultural vehicles trundled through the Belgian capital carrying signs and beeping their horns.
“No future without farmers,” read one of the banners.
Flemish farmers are up in arms over a green push by the government of their Dutch-speaking region aimed at slashing nitrogen emissions from fertilisers and livestock.
The production and use of nitrogen fertilisers generates climate-warming greenhouse gas emissions, as does livestock waste.
The agricultural industry insists it would be too hard hit by the moves which could see some farms deemed too polluting forced to close.
The debate has threatened to split the ruling coalition in the northern Flanders region.
The farmers are also pushing for the regional government to unlock European Union subsidies to their industry that have been held up.