One night last week we were planting a field several miles from home. The farmer didn't have a jug of graphite in his truck since he forgot to grab one when he got the seed buggy. So we ran without it. That fill-up planted fairly well. But when we filled the planter again, and added graphite, the graphite had to work down through the box just like it did the first time we added it. He adds it on top and does not stir it in.
The difference reflected itself in the yield monitor. Until the graphite worked its way down through the boxes, the population was 4,000 to 5,000 lower in seed drop. Plus, two to three rows were sporadically showing reduced performance, although not enough to signal an error or a need for inspection. After running about 10 acres, the graphite had apparently worked its way through the seed in the box. The population stabilized at about 168 to 169,000 seeds per acre in 15-inch rows, up 4,000 to 5,000 from when the graphite was missing. And the variations in row performance disappeared. Each row continually reported working at 100% capacity.
It's just one more indication that graphite and/or talc helps modern planters perform better. There' is also news circulating that some farmers who thought they need 48-cell plates for beans because bean size was so large were able to get by on standard 60-cell plates by using plenty of graphite or talc.
When there is a large error factor built in to soybean seeding rates, perhaps 5,000 seeds per acre difference in seed count isn't significant. But if conditions aren't perfect, the weather doesn't cooperate or other problems develop, that 5,000 extra seeds could come in handy.
Keep plenty if graphite on hand. If you're tempted to skip applying it on top of seed boxes after a fill-up because you're in a hurry, think it over again. Even missing one application cycle can cause seeding rates to drop at the next fill-up, until the graphite works its way back down through the box. This assumes, of course, that you're not stirring the graphite into the seed when you apply it.