As far as i know, applying p when the crop uptake is low just means the soil will just lock it upNitrogen doses - no. It's far too early, cold and there's not enough growth to warrant a tickle.
Phosphate - yes. It won't leach and as long as the run off risk is low, carry on.
Potassium - with higher clay and CEC levels, yes. Hold off if you're on sand.
Magnesium - the sulphur in kieserite is highly leachable. Hold off until there is more rapid growth when the crops can make use of it.