What is the role of potassium in apple production?
Potassium promotes strong vigorous tree growth, boosts fruit size and cell strength. It also encourages good tolerance to pests and diseases
Positive effect of potassium
When soil reserves are low, yield responses have been recorded following potassium applications of up to 600-700 g / K / tree in low density orchards.
Negative effect of potassium on yield
Potassium applications must take into account its level in the soil; when it is high, too much fertiliser can lead to lower yields.
Potassium and Sun Scorch
A high potassium concentration in fruits reduces the frequency of solar scalds. But a high concentration of potassium promotes the appearance of bitter pit. A correct balance K / Ca is therefore important to preserve the quality of the fruits.
Potassium and colouring of the fruits
By playing an important role on the increase of the rate of anthocyanin, the potassium improves the colouration of the fruit. This effect has been demonstrated on several varieties.
Potassium and Bitter Pit
The commonly accepted optimum value of the K / Ca ratio is around 15 for 40-60 g fruits and should not exceed 30 at harvest to minimize the risk of biting pit. This index can be measured on young fruits and used to prescribe the additional sprays needed to correct any imbalances.
Potassium and soluble sugar content
Potassium, through its action in the transport of sugars, plays an important role in increasing the content of SST (or ° Brix).
Related articles
Apple and pear nutritional summary
Most nutrients are stored and retained as reserves in tree buds, bark and roots. These are then remobilized after winter to fuel leaf growth, flower bloom, fruit formation and growth.
Apple agronomic principles
The aim of every apple grower is a high yield of top quality fruit and there are a large number of agronomic factors which can influence this, many of which are within their control given their specific growing systems and climatic/soil conditions.
Apple nutrient requirements
Apple nutrient requirements vary depending on the crop growth stage. Find out which nutrients are most important at different growth stages.
Apple crop nutrition programme
Yara's apple fertiliser recommendations and crop nutrition programmes can help you to achieve excellent growth and maximise the yield and quality of apples.
Identify and diagnose apple nutrient deficiencies
Identify and diagnose if your apple trees are suffering from nutrient deficiencies and learn more about the symptoms and causes and how to control or correct the deficiency
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