Seizing land is a counterproductive and foolish solution to that problem. Basically the whole world uses a different solution, which works pretty well: property taxes (though land-value taxes would probably be better). You just keep raising the taxes until leaving land idle becomes a money-losing proposition. The only way that doesn't work is if ownership of farmland is truly monopoly-dominated so there is no competition, in which case you might have to resort to trust-busting.
This is exactly why we have property taxes, to ensure that most property is put to productive use.
Yes, mass starvation is worse than land seizure, but land seizure is just about the worst possible solution to the problem, as evidenced by what has happened to Venezuela's economy since then. Seizure and collective ownership is guaranteed to produce horribly inefficient operations which might prevent outright starvation but will leave the populace on the edge of it. Seizure and redistribution to private ownership is slightly less bad, but will redistribute the land mostly to people who don't know how to use it effectively.
What would have worked much, much better would be actions that served to restore competition among farmers, starting with making sure they were all paying fair property taxes that were high enough to disincentivize leaving farmland fallow.