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Dec 17, 2008

K+S KALI GmbH answers topical questions

Not only the financial markets, but also agriculture is currently experiencing turbulences. Here K+S KALI GmbH provides answers to some of the urgent questions farmers are asking.


Why are potash fertilisers so expensive?

Potash is mined from underground deposits up to 1.5km deep. The potash content in the crude salts varies considerably and contrary to nitrogen (N), is therefore a scarce resource. Because of the important role they play the global demand for potash fertilisers is great. This causes pricing to be generated on the world market which is influenced by supply and demand as well as production and freight costs.
K+S KALI GmbH is making significant investments in the production of raw materials and their processing, as well as in research and application consultation.


Can I replace mineral fertiliser by farm manure?

Farm manures, or organic fertilisers, play an important role in the agricultural cycle. Particularly in low-livestock regions the necessary soil nutrients cannot be provided by farm manures alone and need to be supplemented by mineral fertilisers (particularly potassium [K], magnesium [Mg] and sulphur [S]). This is not a question of “either/or”, but one of providing both nutrient sources in an environmentally sound and demand-oriented way.

What happens if I cease basic fertilisation for one or two years?

Due to the extensive nutrient removal, mainly by root crops, topsoils may quickly deplete potash stores.   Additionally, Mg and S can be shifted to deeper layers by precipitation, and therefore may no longer be available to crops.  Potatoes may exhibit black spots and decreased yields and quality after just one year without basic fertilisation.


Is it true that dry spells may threaten K-provision to my crops, even on soils with medium K-content?

Yes! Due to dryness in the root segment, nutrients may not sufficiently be absorbed into the plants’ transpiration stream. An additional problem with K may be that this nutrient tends to “bond” with the soil in dry condition, and may therefore be unavailable to the roots. Due to recent climatic changes, this may also be the case in major growing areas of Europe and other countries, where early summer dry spells cause increasing problems. A good supply of fresh K assures that K-concentration in the soil-solution is sufficient, even if water availability is limited.


“Potash saves water” – Is the old adage still true?

Yes, it is. K is one of the most important nutrients for the plant’s water system: it controls opening and closing of the leaf pores, which are responsible for respiration. Beyond that, K regulates water absorption into the cells. Plant, which are well provided with K need less water in order to produce the same biomass volume as plants lacking K.   


Can I use K, Mg and S in order to purposefully improve the quality of my products (potatoes)?

In addition to securing yields, K, Mg and S play decisive roles in determining the quality of agricultural and horticultural products. As a responsible producer, the grower decisively contributes to the quality of the foodstuffs available to consumers, as taste, appearance and nutrient content may be raised significantly by mineral fertilisation.

Left: K-deficiency in potatoes
Right: sufficient K-supply

Numerous trials in Germany and abroad have repeatedly proven the positive effect of basic fertilisation on important quality parameters.

  • Higher contents of nutritious substances
  • More intense pigmentation of fruit, flowers and leaves.
  • Increased shelf-life and processing qualities of harvested crops


Isn’t it enough if I provide nitrogen next year?

It is unlikely but this will be very field specific. Because each nutrient has its clearly defined effects and functions within the plant and because nutrients are not mutually exchangeable, it is unlikely that you can avoid applying any K at all. What is decisive is the correct ratio of nutrients in relation to the others. Excess N will do nothing to raise yield or quality. Numerous field trials have shown that fresh applied K will improve the plants’ absorption of N, thereby minimising luxury consumption i.e. N-losses. S has similar effects. It is therefore indispensable to ensure a balanced nutrient supply!


Which roles do K, Mg and S play for plant health?

In recent years, science has strongly emphasised the relevance of nutrients to plant health. Today, it is standard knowledge that K and Mg are involved in a host of processes creating resistance against plant diseases and pests. S seems to play a particularly important role, as it may be found in many plant-inherent substances immediately involved in the defence against diseases and pests. S-containing phytoalexins, for example, play an important role in building resistance against harmful fungi and bacteria.

Why is sulphur so important for today’s agriculture?

Up until the 1980s, combustion processes (domestic heating, traffic and coal-fired power plants) emitted large amounts of S into the atmosphere, thereby also bringing it to field crops. However, stricter legal limitations and advanced exhaust purification have decisively lowered S-emissions.  As the plants’ demand for S is about as high as its demand for Mg, many soils began to exhibit a significant S-deficiency.  Additional application of S is particularly important for crops with a raised S-requirement, such as rapeseed and cabbages, and for improved plant protein content.

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