Uhh what?
http://vignette2.wikia.nocookie.net/fallout/images/9/9c/FO2_Klamath_Canyon.jpg/revision/latest?cb=20150320145357
http://vignette2.wikia.nocookie.net/fallout/images/4/44/FO2-Klamath-GrazingGrounds.png/revision/latest?cb=20141209233106
http://vignette2.wikia.nocookie.net/fallout/images/9/9d/Fo2_Arroyo_Hunting_Grounds.png/revision/latest?cb=20110210003413
http://vignette3.wikia.nocookie.net/fallout/images/8/8e/ModocBrahminPastures.png/revision/latest?cb=20110612190300
http://vignette3.wikia.nocookie.net/fallout/images/6/64/Farrels_garden.png/revision/latest?cb=20140928224939
No it doesn't. Hence why radiation turns people into ghouls, and mutates animals into giant versions of themselves. Which isn't realistic in the slightest.
All science fiction means is that instead of using "magic" to explain everything, you use "techno-babble".
As shown in NV's NCR Sharecropper farm quests, radiation in the Fallout world actually INHIBITS plant growth. Radiation form the nearby Vault was preventing the crops in the NCR sharecropper farms from going as well as they should have.