The countries importing that food will now have to import from somewhere else. It doesn’t seem to be solving any climate problem, just shifting it elsewhere.
Literally the only reason not to reduce this excessive production is in order to protect established business interests and not rock the boat.
That doesn't meam buying out farms is necessarily the way to go. A lot can be done to reduce nitrate pollution by changing the feed for cattle, letting them roam outside as much as possible (the biggest polluters are factory farms woth thousands of animals), and other measures. But reducing the food production won't cause any problems; it will solve them.
EU farm subsidies shouldn't be rewarding production at any cost, but sustainable production and care for the environment.
Maybe we should export the meat and ship the nitrogen with it and distribute the emissions instead of it all piling up here.