Karl-Johan

On my reading of your results (and I am by no means an expert) your potassium is moving from the old to the young so you have a shortage coming in to the plant.

This is not necessarily the problem. To me the big problem is the low Calcium and Boron. The Calcium cannot be drawn into the plant without Boron. I would be starting with a Boron application. This will bring in the Calcium (assuming it is there). The Calcium will then slow the uptake of the Sodium. This will aid with your Potassium. The increased Calcium should also help with the uptake of the traces.