Sugarbeet

 

The sugar beet has highest nutrient demands

Sugar beet, grown as a feedstock for the production of pure sugar is one of the most important cash crops in the world The continued production of this important commodity requires advanced crop management techniques, and the economical as well as ecological use of any input materials.
 
Within a crop rotation, sugar beet has the greatest demand on the supply of nutrients. Here, not only the main nutrients such as nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg) and sulphur (S) are very important but also trace minerals such as boron (B) and manganese (Mn).

 

There are many benefits to the farmer for growing sugar beet, the broad-leaved crop provides a useful break in intensive cereal rotations, increases soil fertility and complements wide-ranging soil cultivation methods.

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Potassium – the foundation for a reliable yield in sugar beet

• With an uptake of 450-600kg K₂O ha^-1 more potassium is taken up by the sugar beet crop than any other nutrient.
• The largest proportion of the potassium can be found in the physiologically active green foliage, and the potassium content of the storage organ, the beet, is much lower.
• Potassium is known for the positive effect it exerts on yield and sugar content.
• Potassium increases photosynthetic output which in turn results in increased carbohydrate metabolism (sugar synthesis). In addition, potassium is vital for the efficient transport of photosynthetic products and their subsequent deposition in the storage organ (the beet).
• Potassium increases the crops’ resistance to pests thereby allowing healthy crop development to proceed.
• Low potassium concentration in the soil jeopardizes soil fertility and will negatively affect yield and sugar content.

 

Numerous results gained from extensive field trials have demonstrated the significant effect of potassium fertilisation on yield of sugar beet – even where potassium concentrations in the soil appear to be adequate.

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Potassium for improved quality in sugar beet

• The most important factor for quality is sugar content.
• Potassium positively effects sugar content because of its specific physiological effects during synthesis, transport and storage of sugars.
• In trials, the supply of an optimum quantity of potassium resulted in an increased sugar content of between 0.5 and 1% and therefore the value of the beet crop was higher.
• Both potassium and sodium (Na) influence the pH of the raw sugar extract where alkalinity must be minimised for the efficient extraction of sugars.
• In several regions, an additional quality payment is set using the standard molasses loss (SMV). This SMV value is is affected through fertilisation mainly via the content of a-amino-nitrogen which is undesirable in sugar beet.
• After the introduction of this formula for calculating sugar beet quality based on potential sugar extraction, potassium fertilisation has only a negligible effect on the standard molasses loss; this is because small increases in potassium content of beets are overcompensated via a decreasing a-amino-nitrogen-content. Therefore, the standard molasses loss remains mainly unchanged.
• An optimum potassium supply improves the efficiency for nitrogen in sugar beet. 

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High sugar yield through balanced nutrition

To ensure a high sugar yield, the sugar beet crop in addition to nitrogen, phosphorus and potassium requires a good supply of the nutrients magnesium, sodium, sulphur, boron and manganese in a balanced ratio.

• Magnesium has two main positive effects on yield, firstly magnesium helps to maintain the healthy green canopy enabling more sugar to be produced for a longer period of time. Secondly magnesium is crucial in the citric acid cycle (important for cell respiration) where the synthesis of proteins, fats and carbohydrates can be optimised.
• A sufficient supply of sodium improves water efficiency and can partly offset potassium deficiency during dry periods.
• Trial results show an increase in yield of 300-600kg sugar ha^-1 when 20-40kg sodium ha^-1 was applied.
• An adequate supply of sulphur improves sugar quality by decreasing a-amino-N-content. Sulphur deficiency increases standard molasses loss.
• Boron is important for cell development and for production of components such as sugar. Boron deficiency results in heart and dry rot and therefore in substantial yield losses.
• Manganese has similar functions in the metabolism as magnesium. It positively influences yield through, for example by improving assimilation by the leaves during the growing period.

 

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Fertiliser recommendations

Fertilisation in sugar beet production is targetted at enhancing yield, sugar content and quality.

 

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.

 

Recommendations for soil applications 

• An application of 600-900kg Korn-Kali^® ha^-1 to fulfil the requirement for potassium and sulphur. At these rates, Korn-Kali^® also meets a good proportion of the magnesium and sodium requirement. Application on the stubble in autumn is preferable on medium and heavy textured soils and on lighter soils (sands and sandy loams) an application in spring is advised.

   

  Korn-Kali^®

• Soils that are deficient in magnesium but have no lime requirement should receive 300-600kg ESTA^® Kieserit ha^-1 (for soils with mg indices 1 and 0 respectively).

   

  ESTA^® Kieserit gran.

 

Recommendations for foliar applications

• To fulfil the requirement for boron and manganese, a 5% solution using EPSO Microtop^® can be applied between the closure of rows and the end of August (together with fungicide applications).

   

  EPSO Microtop^®