NASA's Earth Observatory has an image of the day feature:
Image courtesy earthobservatory.nasa.gov
From the website:
"Around the world, agricultural practices have developed as a function of topography, soil type, crop type, annual rainfall, and tradition. This montage of six images...shows differences in field geometry and size in different parts of the world.
In Minnesota (first), the very regular grid pattern reflects early nineteenth-century surveying; the size of the fields was determined by the need to have a big enough area to make the use of machinery efficient. Dirt roads separate the fields..."