Food, crops, yields, techniques, revolutions, and so

5. What three systems provide the most of the world’s food?

• wheat
• corn
• rice

6. Distinguish among  polyculture and slash-and-burn-agriculture.

• Polyculture- type of interplanting in which many different plants are planted together.
• Slash-and-burn agriculture- when farmers grow as many as 20 different crops together on small cleared plots. In this type of interplanting, crops mature at different times, provide food throughout the year and keep the soul covered to reduce erosion.

7. What is a green revolution? What limits could these have?
Green revolution is a process that has increased the 88% of the increase in global food production by increased yields per unit of area of cropland. The first stage began in 1950, in MEDC and its mainly caused by technological advances, population changes, and evolution of ecological and social ideologies.
It involves 3 steps:

1. develop and plant monocultures of selectively bred or genetically engineered high-yield varieties of key crops like rice, wheat and corn.
2. produce high-yield by using large inputs of fertilizer, pesticides and water
3. increase in the number of crops grown per year on a plot of land

The limits that this revolutions has rely mainly in lack of water, high cost for small farmers, and physical limits to increasing crop yields.