First, let's address the question of what would happen in such a case:
Lowered tariffs would allow cheaper agricultural products, perhaps of worse quality or produced by cheap or even slave labour, to enter the country. This would have 2 effects:
1) food could become cheaper and many people would be able to afford more food, but perhaps of lower quality
2) local farmers could be driven out of business by the foreign competition and by the lack of subsidies.