http://www.danheller.com/images/FAQ/Tech/Long/img11.html
http://www.lostamerica.com/images/byron/hot.springs.html (look at 35 & 36 specifically)
those are examples of long exposure (and the second link light painting in particular). look at how the ground looks, and remember, these are at dead of night.
take that idea and apply sun instead of moon, sunset/dusk instead of night. see where i am going? you have to know how long exposures effect the exposure of film and know what different lighting conditions will do in combination with long exposures. believe me, if that image is not photoshopped in any way, which i do not believe it is, it is definitly a long exposure at sunset. the grass, its color, and the way the light seems to fall on it (sunset grass with amplified light, the light is NOT directly overhead like some of you seem to think. the way the light on the grass is not light from high-noon.) shadows would be much softer, AND the way the sky looks is what I'd image a sunset would look like with a long exposure.