Comment by Ekaros

Because agriculture is hard industry. The producer prices that is what the farmer gets are often laughable cut from final product. And this is due to farmers having little or no power in the system. Their products are made at certain time. And then they start declining in quality and finally rotting away. Most of the value ends up in other parts of the chain.

You could increase prices relatively little and farmers would earn lot more. But no one else is willing to allow that to happen. As such directly subsidizing them is more efficient.