Get to know potassium nitrate in apple nutrient management



Research shows that the use of KNO3-based fertilizers leads to better color, taste (sugar content) and firmness. Like in many other crops, proper K nutrition also leads to better peal quality, with impact on storability and shelf lite.


KNO3-based fertilizers outperform KCI and K2SO4-based programs- providing faster, more balanced and more efficient nutrient uptake- making them an ideal source for split applications as a tool to manage the fruit size towards the most economical optimum classes. Research indicates that fruit tree nutrient reserve benefit from split and well-balanced nutrition based on KNO3, leading to a better number of flowers, improving yield in the subsequent season.

Research clearly indicates a benefit of using KNO3­based nutrition (NH4+/NO3- ratio 0,2) as opposed to KCI or K2SO4 (both NH4+/NO3- ratio 3,7) in supplying apple fruit trees with potassium.

S.A. Oosthuyse, D.R. Napier and H. T. Holwerda, 2013-2014, Effect of the potassium source, either KNO3, K2SO4 or KCI, in nutrient solutions on the growth of sand­potted peach or apple nursery trees, SA Fruit Journal 13(4): 49-52.

Experience with SQM nutrition programs based on KNO3 in low yielding apple orchards in southern Kazachstan demonstrated significant impact on number of fruits and apple size by the introduction of a KNO3 based program compared to the local program based on urea and K2SO4 based NPK's.

Reference: Observations made by SQM during a Kazach demo trial, 2018.

Research in high yielding apple orchards in Poland additionally shows the possibility to manage fruit size with KNO3 based fertilizers. Extended split application of KNO3 -based fertilizers in apple.

Experience showed that split application management with KNO3 based fertilizers allows to adapt the fertilizers schedule after unpredictable circumstances like drought, diseases or spring frost, leading to better control of the economical size of apples.

1: Control / 2: SOP based / 3-4: KNO3-based / 5: KNO3 based extended split

SQM research commisioned by Fertico Research Agency, 2018.

KNO3 based programs show better color, sugar content and firmness in research trial in Polish high yielding apple orchards

Use of KNO3 as a preferred potassium source results in a more efficient uptake of potassium leading to better sugar transport to the fruit, and anthocyanin synthesis improving fruit coloration. lncreased firmness can probably be related to the synergetic uptake of nitrate with both potassium as calcium.

1: Control / 2: SOP based / 3-4: KNO3-based / 5: KNO3 based extended split

SQM research commisioned by Fertico Research Agency, 2018.

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