Is it possible to read Arifureta Zero without reading Arifureta?
Actually I'm reading the manga already, so I feel a bit lazy to start the novel. Or am I missing something?
An unrelated question (spoiler ahead):
Zero is a prequel, and it doesn't rely on knowledge from Arifureta proper that I remember, so I don't see any reason why you couldn't. You'll miss out on the references, but it's nothing critical. It does spoil some stuff in Arifureta, if you care.
It's much better written IMO, too.
I'm currently reading the main series, based on the reading order Zero should be read after the main story volume 7 to avoid any spoilers: https://www.reddit.com/r/LightNovels/wiki/reading_order
If you plan on reading the main story too, you should probably read it first. Personally I read a bit of the WN and the manga too, but I've been reading the LN lately (I'm up to V3 start) and there are quite a few things that are missing in the manga (just like any adaptation).
Like @flarecde said, you'll only miss out references. But so far, they really aren't that important. Even if you do read the main series, IMO some of the references are actually kinda hard to spot.
It's not necessary, but you sure will miss a lot of good references. I really recommend you to read the main series up to vol. 7, then Arifureta Zero vol.1, then Arifureta vol. 8.