I'm reseeding a field, grazing to grazing. The potassium level is high (3.1) but the phosphorus level is slightly low (1.7).
I don't want to bump up the potassium any more but needing a little phosphate.
Should I use a compound fert or just phosphate or nothing on the seed bed??

Also, would I be best to apply nitrogen at seeding or wait until the field has greened over?

Thanks. I should know this stuff but I've made a mess of reseeds in the past... needing this to go well.