This verse intrigued me because I have no idea what the salt covenant was. I found this
The author mentions that the salt covenant is is a symbol of incorruptibility and permanence. The act of eating together is a bonding commitment. So adding salt to the offering showed the covenant as permanent and indestructible.
K: Lord I pray I add enough salt to my spiritual life to show that my covenant with you is permanent and indestructible. I do not want to take your word lightly. Amen.