Fresh & Flavorful: Potassium’s Impact on Crop Quality & Shelf Life

Producing high-quality produce is a key strategy for achieving the best price in any market conditions, and a proven method to improve the quality is to ensure crops receive adequate potassium. Often referred to as the “Quality Element” in crop production, potassium plays an essential role in improving many different quality attributes.

Organoleptic Properties

Quality can refer to many aspects of crop production, but in this article, we will focus on the organoleptic properties of crops. The term organoleptic refers to what our senses can determine, such as how something tastes, smells, looks, or feels. For many crops, ensuring adequate potassium fertilization improves all these characteristics.

When growers choose to use potassium to improve quality, ICL’s high-quality potash fertilizers are an excellent choice. Backed by ICL’s professional agronomic and technical teams, our high-quality potash fertilizers contain 62% K₂O, ensuring they deliver the potassium plants need to thrive.

How Potassium Improves Quality

Potassium has an irreplaceable role in activating enzymes fundamental to plant metabolic processes, especially for protein and sugar production. However, this biochemical function only requires small amounts of potassium. Plants need much larger quantities of potassium to maintain the water content and thus the turgor of cells – a biophysical role. Turgid cells maintain the leaf’s vigor, ensuring photosynthesis proceeds efficiently. The relationship between the water and nutrient content of the cell controls the movement of both through the plant, as well as the transport of sugars produced by photosynthesis to storage organs like grains, beetroots, tubers, and fruits. These physiological functions are crucial for creating the best quality produce.

For example, potassium increases the size and sugar content and improves the flavor and color of fruit and vegetables. It also increases the produce’s attractiveness by promoting uniform and larger fruit with a consistent shape and attractive color. But potassium is not just essential for the quality of produce, it also improves the shelf life of produce and reduces the incidence of blemishes, markings, mechanical injuries, and signs of disease.

Effect of potassium on citrus fruit size. Credit: A.R.O., Volcani Center, Israel

Improving Shelf Life with Potassium

There are many examples that demonstrate how potassium improves the shelf life of fruit and other produce.

• Generally, potassium reduces the rate of senescence and decreases the rate of numerous physiological diseases in crops.
• Potassium increases firmness and strengthens fruit skins, reducing damage during transport and resisting decay, keeping produce fresh for longer.
• Increasing potassium application reduces postharvest moisture loss by increasing the weight of the harvested organs and maintaining tissue integrity.
• Potassium can reduce the incidence of fungal storage diseases that may cause considerable losses, given that fruits, tubers, or roots showing even minor damage must be discarded before marketing.
• During storage, metabolic processes gradually break down sugars, starch, and organic acids into carbon dioxide and water. This rate of decay increases with a shortage of potassium, meaning fruit does not last so long in storage.

Enhancing Produce Quality with Potassium

The importance of potassium for quality can be seen clearly in bananas, tomatoes, potatoes, onions, and many other crops, where potassium enhances the storage and shipping quality of produce and extends its shelf life.

• Poor potassium nutrition of bananas results in thin and fragile bunches with a shorter shelf life.
• The quality of citrus fruits during storage is influenced by the potassium nutrition of the tree. The incidence of stem-end rot and green mold decreases as potassium application increases, reducing fruit loss during transport and increasing supermarket shelf life.
• For the orange cultivar Shamouti, potassium reduces the incidence of superficial rind pitting, a physiological disease that develops in the packing house within 3-5 weeks after harvest and during shipment and storage.
• For potatoes, applying potassium reduces storage losses related to a reduction in the activity of catalase and peroxidase enzymes.
• In carrots, potassium enhances the keeping quality after harvest.
• Increasing potassium application reduces the incidence of endogenous brown rot, one of pineapple’s most significant physiological postharvest disorders.

In papaya, in addition to increasing the fruit yield, trials in India showed how increasing potassium application also improved 3 major papaya quality parameters. Potassium increased the thickness of the edible part of the fruit (the pulp thickness), increased the sweetness of the fruit (measured as the Total Soluble Solids TSS), and reduced the acidity of the fruit.

Effect of K application on papaya fruit yield and quality. Source: IPI (International Potash Institute)

Optimum Potassium Application

Understanding the needs of individual crops and the impact different quality attributes can have on market price is central to determining the optimum potassium application rates. In many cases, the amount of potassium required to achieve the optimal crop yield will also be sufficient to secure good quality. But in situations where the need for enhanced quality is more important than other aspects of yield production, as is often the case with fruit produce, it is vital to pay attention to the potassium needs of the crops. In these situations, increasing the potassium application to improve the produce’s taste, look, size, or shelf life can improve the overall economic return.