Safety stock not show in one of my erpnext

I have 3 erp next in one server on different port , on one of that when i open any item in purchase setting there is not field of safety stock , but in other two erp i have this open , some one knows what’s problem why in one erpnext i don’t have this feature ?
all in same version of 10.1.35 master

See if it is hidden in Customize Form?

yes , thanks so much , it’s solved .