Columbia subject headings:
Harvard subject headings:
Fertilizer industry--Central America.
Grain--Diseases and pests--Central America.
Grain--Fertilizers--Central America.
Pesticides industry--Central America.
Princeton subject headings:
Agricultural chemicals--Economic aspects--Central America.
Agriculture and state--Central America.
Farms, Small--Central America.
Fertilizer industry--Central America.
Fertilizers--Central America--Marketing.
Grain trade--Central America.