The foreign agricultural workers who seek seasonal agricultural work in US can enter the States and work there through H2A visa. This visa program is only for nationals of that country which have been designated as eligible by the United States. The US employer has to sponsor the worker to work in the agricultural land.
The H2A visa to issued to foreign nationals of Argentina, Australia, Barbados, Belize, Brazil, Bulgaria, Canada, Chile, Costa Rica, Croatia, Dominican Republic, Ecuador, El Salvador, Estonia, Ethiopia, Fiji, Guatemala, Haiti, Honduras, Hungary, Iceland, Ireland, Israel, Jamaica, Japan, Kiribati, Latvia, Lithuania, Macedonia, Mexico, Moldova, Montenegro, Nauru, Nicaragua, New Zealand, Norway, Papua New Guinea, Peru, The Philippines, Poland, Romania, Samoa, Serbia, Slovakia, Slovenia, Solomon Islands, South Africa, South Korea, Spain and Switzerland.