Low soil potash levels contribute to increased cereals lodging risk and growers should prepare to include K with spring nitrogen fertiliser, the Potash Development Association (PDA) has advised.
Potassium strongly affects the thickness of cell walls and any deficiency (below a soil K Index of 2) will reduce straw strength and increase the threat of lodging, said the PDA’s Chris Dawson.
“For cereals on light soils, where the soil K levels are often low and are difficult to raise if clay content is low, then there can be an advantage from including some K with spring nitrogen as an NK top dressing.”
If the soil K Index is satisfactory, then potash can be applied at any convenient time – if not in the seedbed, then during the winter, he noted.
A wheat crop yielding 10t/ha, with the straw removed, will remove almost 120kg K2O per hectare from the field, he said. This compares to 56kg K2O/ha if the straw is not removed but is chopped and incorporated in the field.
“The cost of 95kg K2O/ha would be covered by about a third of a tonne of wheat, so it doesn’t make sense to risk yield and quality by neglecting potash.”
Further information can be found at www.pda.org.uk