How Do Interactions among Earth's Spheres Vary Regionally?
ES0108  Farm Fields from Space

These images were taken by a camera on board a space shuttle. The camera was looking down at Earth from approximately 200 km above its surface. Each image shows large farm fields.

  !   Click each image to examine a larger version.

NASA EarthKAM
Farm fields cover the countryside in Argentina, South America. Argentina is one of the world's leading producers of food. Dark areas in the image are bodies of water, and white patches are cities.
NASA EarthKAM
Circular fields are visible among sand dunes in the desert of Saudi Arabia. These pivot-irrigated fields have a well at the center that pumps groundwater to the surface. A sprinkler arm extends from the center, and rotates around the field like a hand on a clock, watering the circular area beneath it.

Differences in how crops are distributed across the land can reveal how Earth's spheres are interacting. In places where vegetation (biosphere) is healthy and abundant, ample amounts of rain (hydrosphere) must be available. Places where vegetation is scarce can be inferred to have limited supplies of water (hydrosphere) at the surface.

1. For each location, tell how you think the crops get their water. What Earth system processes can be inferred at each location?

2. Which of the two images more closely represents how crops receive water near your home? Is the hydrosphere abundant or scarce at your location?


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