There are many different economic issues that relate to agriculture. The issues are different in different countries.
For example, in many developing countries, the major economic issue relating to agriculture is the need to make it more efficient. Agriculture in such countries is typically not very mechanized or modernized. This means that farmers cannot produce very much output on a given area of land. This makes them poorer. It also means that they have a harder time competing with farmers from the rich world if their countries open their markets to free trade.
An economic issue in the United States with regard to agriculture is how to prevent the sale of too much agricultural land. Farming is not an easy business even in a rich country. There are many farmers in areas near to cities who are willing to sell their farm land to people who want to build houses on the land. This makes economic sense for the farmers because it gives them a lot of money. However, it may be bad for agriculture in the long run as it takes away good farm land forever.