Yes, FERTILIZATION is a Scrabble word!

Letter values in Scrabble US: F 4, E 1, R 1, T 1, I 1, L 1, I 1, Z 10, A 1, T 1, I 1, O 1, N 1.

Is it a valid word?

FERTILIZATION is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

creation by the physical union of male and female gametes; of sperm and ova in an animal or pollen and ovule in a plant
making fertile as by applying fertilizer or manure

Not playable in Scrabble US: FERTILISATION.