If the lands is converted for industrial use, where we shall produce food from plant origin?

Answer 1

The history is that we always pave over the best land.
There is a marked increase in hothouse and hydroponic production over the last 20 years though. It might be how most food gtets grown in the future. Certainly it is becoming important for crops that require a lot of water like tomato, lettuce and other green vegetables.

Answer 2

Yield from the crops is steadily being increased by better management including selection of high yielding variety, pest control, water management etc.

Also, generally non-agricultural land is used for industrial purpose and where agricultural land is needed, other dry land is opened for agriculture.

Answer 3

there you see the problem. everyday valuable cropland is turned to malls, housing projects , and industry. and with the population ban it doesn't matter that we get a bit more yeild from the paltry acres we maintain, we will run out of food.