The need for Canada to populate the land with people loyal to them and to have them send western resources east.
Rosa parks arrest on the montgomery alabama bus december 1955 sparked the boycott over 1955 to 1956 to make a mass protest to the supreme court to end the segregation rule on public buses
Samuel Slater invented the cotton gin which cleaned the cotton faster.
Government Debt.
Corruption.
Extreme weather.
Lack of control in local food.
Lack of access to education.
Mental illness - lack of proper psychiatric care.
World hunger.
Epidemic diseases.
Honestly, none. The union didn't really have any agricultural advantages over the Confederacy, in fact, it can be argued that agriculture was one of the biggest disadvantages of the union.