My cousin and I used to shoot arrows into a field (next to his house) to see how far they would fly. When we were done we'd run through the field, or send his sisters out to fetch them. We never found all of them.
Forty years later my uncle, upon preparing to sell this piece of land, found six or seven arrows lying on the ground, some partly buried in the soil. Three of them were in almost perfect condition, which amazed us kids (now middle-aged adults.) They were wooden arrows with metal tips (probably aluminum) and real feathers, bought at K-Mart in the late 1960's.
So yeah, some arrows might be okay; others rotted through. All depends.
(I live in New England, hot summers; cold, snowy winters; a good amount of rain; temperate forest. The area I am talking about was once a pine and maple forest with open meadows here and there. So the ground is often wet, the soil slightly acidic.)