To encourage the production of a type of crop, the government gives a payment to farmers

An agricultural subsidy (also called an agricultural incentive) is a government incentive paid to agribusinesses, agricultural organizations and farms to supplement their income, manage the supply of agricultural commodities, and influence the cost and supply of such commodities.

Explanation:

supplies had to travel a long distance across water on ships that were often attacked, so they did not reach europe

when a country suffers, for example, a drought period, the market product is affected for a low offer, in this case, potatoes; the government has to tax to the households, which have to give more money for the potatoes which they consume, that situation make them consume substitute goods even through loans, it could increase the financial market movement and the inflationary phenomena, the business has to increase salaries in order to the employees could buy a more expensive food (potatoes) and in order to inflation tha business had to buy expensive supplies in the factor market, while the rest of the world have to gain more money to consume the same amount of potatoes.