Columbia subject headings:
Agriculture--Environmental aspects--Africa, Eastern.
Agriculture--Environmental aspects--Africa, Southern.
Organic farming--Africa, Eastern.
Organic farming--Africa, Southern.
Harvard subject headings:
Organic farming--Africa, East.
Organic farming--Africa, Southern.
Princeton subject headings:
Agricultural ecology--Africa, Eastern.
Agricultural ecology--Africa, Southern.
Agriculture--Africa, Eastern.
Agriculture--Africa, Southern.