So I spread several tons of mixed P & K fertilizer with zinc in it the past week. Any of you that have ever spread and handled much bulk fertilizer knows you will end up breathing in a good bit of dust from it.  I wonder if this qualifies as a zinc treatment and how soon I might need another dose of it. We got over all our ac with the mixed fertilizer but did catch a barrel full when the auger truck choked up. I might need to spread it on the garden with the hand spreader in a few days as I always get a good dusting using it.