Dont know about South America but I’ve seen recently a UN climat change report that says the increase in cultivated land will mainly come from Canada and especially Russia (think Siberia).

No trade barriers please. And we, grain traders, will ensure, the world is adequately fed with notably Black Sea wheat (the cheapest and one of the best quality-wise). Governments will never guarantee this, just let private traders work.

https://www.bloomberg.com/news/articles/2019-05-17/commodity-traders-could-be-a-key-beneficiary-of-climate-change