The government is taking measures to augment the country's food supply.

Augment : make (something) greater by adding to it; increase.
Prohibit : formally forbid (something) by law, rule, or other authority.
Decrease : make or become smaller or fewer in size, amount, intensity, or degree.
Surpass ; exceed; be greater than.
Compensate : give (someone) something, typically money, in recognition of loss, suffering, or injury incurred; recompense.

Antonym of Augment is Decrease