Before Robert Mugabe took power in Zimbabwe, it was a net exporter of food and a reasonably prosperous country. But that changed after Mugabe was elected.
Among other things, Mugabe stripped white land owners of their farms and turned them over to blacks, socializing the production of agricultural goods. The whites were not compensated for the seizure of their property; they were just thrown off the land. The lucky ones were arrested if they refused; the unlucky ones were tortured and killed by gangs. (No one has alleged any racist motives for this.)
Since all that started, the productivity of farms in Zimbabwe has plummeted. Zimbabwe now must import its food, and its economy is collapsing.
People who were given land have not fully utilized it. The people who previously owned the land were professional farmers, who knew what they were doing; the people that now occupy the land are unskilled in agriculture. This has limited the productivity of the land that is actually being worked.
But according to other reports, much of the former farmland is going fallow. There is no one working it; the people who were working it productively have been driven off, or tortured and killed. The new tenants don't work it, or work it ineffectively; they don't really care, though, because the land was just given to them.
Now Zimbabwe is forced to spend its hard currency on importing food; this is money which would otherwise have been spent on goods and services the nation cannot make for itself. The end result is discussed in the linked article, above.
The first time I read an article about Zimbabwe under Mugabe--in 1999!--I knew that it was a real-world, real-time example of how socialist government ruins an economy.