Strategies for Avoiding Potassium Deficiency
1. Examine paddock history.
Long term cropping or a history of high nutrient removal may indicate a potential for potassium deficiency.
2. Take soil tests.
Soil apply potassium fertilisers if levels are below critical.
3. Assess the susceptibility to Premature Senescence (PS).
What variety is being grown? What boll load is present? What is the probability of waterlogging or other stresses such as extended cloudy weather? Has this field displayed PS symptoms in the past?
4. Consider foliar potassium applications of potassium nitrate if PS susceptibility is high.
Preventative foliar sprays of 4kg potassium/ha at four 1-2 week intervals starting soon after first flower can improve yields and provide some protection from PS.