A higher concentration of potassium in apples reduces the incidence of sunburn/sunscald. However, potassium needs to be in balance with calcium, as these two nutrients compete with each other and can lead to poor calcium content in fruits, resulting in storage problems and other disorders related to calcium deficiency.
Avoiding Apple Sunscald or Sunburn
Sunscald or sunburn in apples accounts for yellow or flushed areas on the fruit skin due to direct sun damage often following a period of cooler, cloudy weather. In severe instances, the scald damage turns dark while the fruit is still on the tree, with the underlying tissue becoming spongy. It is also associated with poor calcium content in the fruit. A balanced crop nutrition can help avoid sunburns.
Crop Nutrition and Sunscald / Sunburn
Potassium
By improving calcium content in the skin and pulp, cells are less liable to damage and subsequent breakdown, thereby avoiding sunscald damage in apples.
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