Managing the Sugar/Acid Ratio in Top Fruit

Top fruit flavor and taste are related to the level of soluble solids in the fruit, which are mainly sugars. Total Soluble Solids (TSS) is therefore of extreme importance to measure the quality of top fruit. Referred to as oBrix, TSS is assessed by refractometry or near-infrared spectroscopy and can be used to check fruit maturity and ripeness, important to determine harvest timing. A balanced crop nutrition can influence TSS content of fruit.

Crop Nutrition and Top Fruit TSS Content

Nitrogen and Potassium

Nitrogen has a positive effect on the soluble solids content of apples and pears. Potassium also plays an important role on sweetness, measured by oBrix, as shown in trials in India. °Brix is used to approximate the TSS content because the soluble sugars usually represent more than 75 - 85% of the soluble solids.
Nitrogen and Soluble Solids
Potassium and TSS Content

Magnesium

Magnesium and Fruit Acidity

Apple acidity is a relevant characteristic for both fresh and processing markets. It is one of the main group compounds determining flavour. The higher the level of acidity, the more tart the flavour and the better the thirst-quenching properties of processed soft drinks. 

Magnesium has a slight effect on fruit acidity.

Recommended Yara Fertilizers for Top Fruit

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YaraMila COMPLEX

12-4.8-14.9 + 8% S - Prilled NPK fertilizer which also contains magnesium and sulphur as well as micronutrients ideal for use on a wide range of arable and horticultural crops.

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YaraLiva TROPICOTE

15.5% N + 19% Ca - Granular calcium nitrate fertilizer for field application to a wide range of crops.

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YaraVita ZINTRAC 700

A fully formulated flowable liquid micronutrient fertilizer containing 700 g/l zinc for foliar application to prevent and treat zinc deficiency on a wide range of crops.

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YaraVita BORTRAC 150

A liquid micronutrient fertilizer containing 150 g/l boron for foliar application to provide additional boron or to treat boron deficiencies in a wide range of crops.

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YaraVita SENIPHOS

A liquid micronutrient fertilizer containing high concentrations of phosphate and calcium for foliar application to improve yield and quality in fruit and potatoes.

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YaraVita STOPIT

A liquid micronutrient fertilizer containing 160 g/l calcium for foliar application to control and reduce calcium related disorders in top fruit and other crops.

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YaraVita BUD BUILDER FL

A flowable liquid suspension fertilizer with nutrients and micronutrients including magnesium, zinc, nitrogen, boron and phosphate for foliar application to improve the flowering of top and soft fruit.