NGN - Determining optimal potassium levels and management options for the West Midlands regions

Growers in the West Midlands region have identified potassium (K) deficiency as an ongoing constraint limiting yield potential in sandy soils. While growers agree that replacement potassium was likely being underapplied over the years, the majority also thought potassium needed further research, mainly around ‘response by soil types’ and ‘application rates’ and ' the ability of some plants to recycle K from depth'. They especially wanted to know when additional K may profitably benefit the crop in terms of ‘timing and method of application’. There is concern that diagnostic methods, surface tested Colwell K, was not providing an accurate picture of the level of potassium unavailability.

Fertiliser supplier trials typically indicate low levels of K in many of our soil profiles 0-30cm, with responses to K application. Top of mind for growers: What is the potential yield loss that is not evident due to a nutrient throttle on production?