Potassium Research and Agricultural Production - The International ...

Improvement of potassium nutrition leads to greater resistance to low temperature
in such potassium loving plants as potatoes or buckwheat. On the contrary the resistance
of calcicole plants (e.g. maize, soya beans) to low temperature increases through
improved calcium nutrition [J].
Potassium has a large effect on the physical state of cell colloids promoting their
swelling. Potassium raises turgor and reduces unnecessary water evaporation by the
plant. Lack of potassium can lead to severe dehydration of plant tissues during dry
and hot weather.
The lowest concentration in the solution at which plants can still assimilate potassium
is 0.01 mg K 20 per litre [J]. Severe potassium starvation is accompanied by thecharacteristic
symptoms of potassium deficiency [27], delay of growth and development and
consequent yield decrease and deterioration.
Potassium plays an important role in improving the quality of farm crops. The following
examples of the positive influence of potassium have been mentioned: increased
sugar accumulation in sugar beet, sugar cane and grapes, improved fibre quality of
cotton and flax, the improvement of tobacco aroma and combustibility, the increase
of oil content in sunflower seed and soya bean, better quality of fodder grasses and the
improvement in appearance of fruit and vegetables. The positive effect of potassium
on potato yield and the content of starch in tubers is shown in table 4.
Table 4. The effect of potash fertilizers on the yield and quality of potatoes (28)
Soils Yields indices Yields Response to Number
without of tests
potassium muriate potassium
sulphate
Sod-Podzolic, sandy loam and Tubers, m.c./ha 172 19 21 17
sandy soils Starch, % 15.1 14.8 15.1
Yield of starch
m.c./ha 26.0 2.4 3.7
Sod-Podzolic loamy soils Tubers, m.c./ha 217 20 22
Starch, % 16.5 16.1 16.4
Yield of starch
m.c./ha 38.6 1.9 3.2
The effectiveness of different potash fertilizers depends on accompanying anions.
These differences in efficiency are attributed mainly to antagonism of ions in the processes
of plant nutrition, differences in fertilizer solubilities and their capacity for the
change of soil solution concentrations, the influence of the ions on the physiological
processes and chemical plant composition [29].
The rational application of every 100 kg of K 20 leads to the increase of yield by
0.1-0.2 t{ha of raw cotton, 3.5-4.0 t{ha of sugar beets, 2-3 t{ha of potatoes, 0.15 t{ha
of flax-fibre, 0.3-0.5 t{ha of winter cereals and 2-3 t{ha of summer cereals, 2.()"'2.3 t{ha
of sown grass hay and so on [30].
Effectiveness of potash fertilizers would be the most if we shall have in mind the all
of physiological aspects of the role of potassium on the growth of plants, their development
and the processes of metabolism.
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