Nutrient supply potato
In recent times, the range of uses for potatoes has steadily increased. Besides the traditional use as a food, the importance in the area of non-food products is ever-increasing. For example, the extracted potato starch is used as a raw material in paper manufacture, building materials, adhesives, cleaning materials, pharmaceutical products and also in both the biotechnology and cosmetic industries.
The economic viability of the potato crop is determined by yield and quality. The foundation for success includes not only the selection of suitable varieties tailored to the target market, but also an advanced crop management program. Adequate fertilisation, as well as crop protection is vital for potato crops as the requirement for nutrients by this crop is considerable. Fertilisation which is tailored to the yield potential also positively affects many quality characteristics. In addition, the resistance of plants and the shelf life of tubers are enhanced.
Potassium has a significant effect on yield and quality because of all the nutrients, potassium is taken up in the greatest quantity, indeed the potato crop takes up approx. 60kg K2O per 10t tuber yield.
Potassium has a positive effect on:
The desired quality of potato crops depends on the targeted endproduct (table, processed, starch or seed potato). For example, processed products such as crisps and chips require a medium to high starch content while starch production requires a high starch content.
The starch content is less important for cooking potatoes, however here cooking quality of potatoes is very important. This means that potatoes should not disintegrate when cooked and should not discolour.
To meet these diverse demands on the quality of potatoes, the selection of suitable varieties as well as adequate fertilisation are important.
In particular, the nutrient potassium influences many quality characteristics which in turn positively affect the proportion of marketable product:
Potatoes are frequently grown on lighter soils where the supply of magnesium must be guaranteed using fertilizers.
Magnesium is essential for the assimilation of the plant and affects not only protein and carbohydrate synthesis but also their transport and storage in the tuber.
Magnesium as well as manganese increases the concentration of valuable components such as citric acid and vitamin C. In addition, they enhance the resistance of tubers against discoloration during processing. The increased concentration of organic acids is responsible for this because they lower the pH value of the tuber and, therefore inhibit enzyme dependant reactions.
Boron is important for cell development, stabilization of cell walls and for the synthesis of energy rich components such as sugar and starch. The positive effect of magnesium (and the trace minerals manganese and boron) on the reduction of black spot of potatoes has been confirmed in field trials with EPSO Top® and EPSO Microtop®
Fertiliser is applied in order to maintain the fertility of the soil so that its natural yield potential can be protected over the long term. This requires the maintenance of an optimal nutrient content in the soil. Nutrients removed with the harvest have to be replaced through an adequate application of fertiliser. Together with the replacement of removed nutrients adjustments have to be added for site specific losses (for example: leaching or erosion).
The total removal of a plant results from the nutrient uptake of the main crop (e.g. grain, tubers or beets) and the uptake of harvest residues (e.g. straw, leaves). If the harvest residues remain on the field, only the removed nutrients by the main crops have to be replaced.
The nutrient potassium (as potash) is best applied exclusively in the sulphate form since potatoes are susceptible to chloride toxicity. The best time for application of potash is generally just before planting.
The table shows fertiliser recommendations calculated on the nutrient uptake of the main crops on base of an optimal soil nutrient content. Adjustments for site-specific losses due to leaching, fixation or erosion are not taken into consideration.
| Total removal (incl. harvest residues) | Removal through main crop | Fertiliser recommendation due to nutrient uptake with optimal nutrient soil content class (per hectare) |
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|---|---|---|---|---|---|
| Total removal of | Through main crop | ||||
| (kg ha-1) K2O / MgO / SO3 |
(kg ha-1) K2O / MgO / SO3 |
Potassium | Magnesium | Potassium | Magnesium |
| Tuber yield 40 t | |||||
| 270 / 22 / 25 | 240 / 16 / 22 | 900kg Patentkali® | 90kg ESTA® Kieserit | 800kg Patentkali® | 65kg ESTA® Kieserit |
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20-25kg EPSO Top® ha-1 in a 5% solution (5kg per 100l) for magnesium- or sulphur deficiencies
20-25kg EPSO Microtop® ha-1 in a 5% solution (5kg per 100l) for high periods of high demand as well as control of latent deficiency of magnesium, sulphur, boron and manganese.
Fertilisers which may be applied for this crop
Our audio track provides valuable information on optimising the nutrient supply to potatoes, as well as the effects on marketable tuber yield, starch content and deep-frying colour. listen
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