Potassium deficiency causes injuries to Picea pungens glauca in nurseries

For many years a widespread disorder has occured with Picea pungens glauca in nurseries near Hamburg, with chlorotic and sometimes necrotic needles at the tip of current shoots. From a survey investigation, a pot trial and a field trial it was concluded that K deficiency was the cause of the disorder, and that it was probably aggravated by oversupply of N.