Only 12 percent of the Earth’s ice-free land surface is suitable for growing crops – that is, about 13 billion hectares. The rest is either too wet, too dry, too cold or too steep. Or the soil is too shallow or poor in nutrients.
A much higher proportion of Europe has fertile soil (36 percent) than any other continent. About 31 percent is cultivated.
In North America 22 percent of the land is fertile but only 13 percent is cultivated, partly because much land is lost under concrete. Surprisingly, 16 percent of Africa is potentially fertile, yet only 6 percent is cultivated.
Southern Asia is so crowded that even though less than 20 percent of the land is fertile, over 24 percent is cultivated.
Dairy farms produce milk, butter and cheese from cows in green pastures in fairly moist parts of the world.
Mixed farming involves both crops and livestock as in the USA’s Corn Belt, where farmers grow corn to feed pigs and cattle.
Mediterranean farming is in areas with mild, moist winters and warm, dry summers – like California, parts of South Africa and the Mediterranean. Winter crops include wheat and broccoli. Summer crops include grapes and olives.
Shifting cultivation involves growing crops like corn, rice, manioc, and millet in one place for a short while, then moving on before the soil loses goodness.
Shifting cultivation occurs in forests in Latin America and Africa.
There are now over twice as many farm animals in the world as humans – over 14 billion.