Use 2 parts trace mineral, 1 part di calcium phosphate, 1 part stock salt. You can buy most of this at any feed store. Works better than anything Ive tried over the yards and you can get it under $30 and it makes about 200 lbs so you can make several stations with it. Turno the soil over about 4 feet around, dump about 50 lbs, mix in with soil and thats it. My mineral stations get hit harder than my corn feers. Good luck