18°
Austria
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FERTILIZER

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  • Soil texture
    Light to medium-heavy, sieveable soils
  • Min. temperature
    Growth from 8°C
  • pH
    Tolerant of slightly acidic to slightly alkaline soils: pH optimal: 5.5-7.5
  • Water demand
    Min. 160l/m²
  • Vernalisation
    3-4 weeks at 8-12°C aeration
  • Plant density
    Depending on date and variety 3-4 tubers/m²
  • Seeding Depth
    10-12 cm
Potatoes

Potatoes (Solanum tuberosum) belong to the nightshade family. They are exceptionally well adapted to our temperate climate, though they do not tolerate frost and the water demand is relatively high. An even distribution of rainfall is needed to achieve high yields. With sufficient rainfall (>160l/m²) and good distribution in the months from May to August, yields of up to 50t/ha (approx. 20t/acre) can be expected.

Key facts
  • Healthy seed potatoes and loose soil are important.
  • Supply sufficient potassium and phosphorus in autumn and early in spring.
  • Use suitable nitrogen fertilizers before forming ridges.
  • Potash fertilization in autumn or low chloride NPKs in spring.
General Information
General Information
Nutrient Demand
Nutrient Demand
Fertilization
Fertilization
FOR POTATOES A STABLE WATER SUPPLY IS CRUCIAL

Potatoes do not prefer any particular soil type. They thrive in both sandy and heavy soils. The best soils for potatoes are high in organic matter and loose soils with sufficient water retention capacity. Depending on the variety and purpose (starch, table or seed potatoes), this crop is very adaptable. They are planted early in the year (end of March to mid-April) and the soil should be as dry as possible. The seedbed should be finely crumbly and dry to a depth of 10-15cm. The ideal plant density at 75cm row width and 40-44cm placement distance in the row is 30,000-33,000 plants/ha(12,150-13,360 plants/acre).

Optimal nutrient supply for starch potatoes
Nitrogen fertilization is mainly responsible for the yield and has the highest influence on quality. A good nitrogen supply promotes tuber growth in particular. The first dose of nitrogen should be applied before ridges are formed, allowing good incorporation into the soil. Potatoes need nitrogen very early to help build up foliage. Approximately 90% of the absorbed nitrogen is needed before flowering. Late application of nitrogen or it being available too late leads to a decrease in starch content. Potassium is the nutrient with the second highest effect on the yield. Starch content in tubers is directly influenced by potassium fertilization. In addition to the amount of nutrients, the form of the fertilizer plays an important role. Potatoes are chloride-sensitive plants; chloride prevents starch in the leaves from shifting to the tubers. Chloride-containing potassium fertilizers used in spring can reduce the starch content. Phosphorus is an essential element in both tuber formation and secondary tuber growth. As an energy source, phosphorus promotes starch formation and its transfer to the tubers. After flowering, potatoes require a considerable amount of magnesium. Foliar fertilizers (L.A.T SUPREMO products) containing magnesium can be added to protect the plants.

Extraction quantities for potatoes

Element

Uptake

(Unit/t of production)

Removal

(Unit/t of production)

Sensitivity to deficiency

N

4.4

2.8

Very Sensitive

P2O5

1.1

0.9

Very Sensitive

K2O

5.9

3.9

Very Sensitive

MgO

0.5

0.3

Very Sensitive

SO3

0.7

0.4

Sensitive

TE

Up to 500g/ha (approx. 8oz/acre) manganese (Mn) where required

The table shows uptake and extraction per tonne of starch potato yield. A potato yield of 50t/ha takes up 220kg N/ha. If 50kg N/ha is supplied from the soil and the N-supply from a leguminous intermediate crop of 30kg N/ha is added, 140kg N/ha fertilizer would still need to be applied. The harvest removes 140kg N/ha from the field.

Like all root crops, potatoes react very strongly to phosphorus and potash fertilization. As a rule, the base fertilization is done before the potatoes are planted. An application before the formation of the ridges supports homogeneous mixing with the soil and promotes rapid absorption through the roots.

Starch potato yield parameters:

  • Starch content for potatoes
  • Harvest in t/ha

First application

Second application

First application

Basal fertilization prior to planting:
A large proportion of the fertilizer is spread before potatoes are planted. A NPK compound fertilizer is best, providing all required phosphorus and potassium and most of the nitrogen (do not use chloride-containing K-forms). Nitrogen can be ammonium-enriched, via nitrogen-sulphur forms, and added as urea, where 100-120kg/ha of nitrogen would be adequate.

Second application

Starch potatoes need a sufficient supply of nitrogen:
Two to four weeks after planting or up to the four to eight leaf stage, a second fertilization with pure nitrogen is applied to starch potatoes since the need for leaf growth is considerably higher than with table potatoes. Depending on the first application, 50-70kg N/ha should be applied at the second fertilization and it must be rapidly effective (nitrate nitrogen, NAC 27 N). Any delay in N availability will reduce starch content.