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PHOSPHORUS
The phosphorus is an absolutely necessary element for plants. It is found in the plant in mineral form or in the form of organic compounds. The lack of phosphorus causes serious disorders.
The plants remain small, the leaves become discolored, the roots stop growing, the leaves fall and production decreases. The lack of phosphorus leads to the nitrogen starvation even if there is enough nitrogen in the soil. The excess phosphorus becomes toxic for plants and leads to infertility, and the premature yellowing of the leaves. Out of the phosphorus in the soil the plants use 1-5%, namely the one which is soluble. The content of phosphorus is expressed by P2O5 parts per million. Poor soils have below 20 parts per million. Middle soils have between 40 and 80 parts per million. Very good soils have over 160 parts per million.
POTASSIUM
The role of potassium in the plant is multiple: it intensifies the absorption of water, it reduces transpiration, it favors the synthesis of carbohydrates, lipids and proteins, it intensifies photosynthesis, it stimulates the cell division and the growth of plants. The lack of potassium in the plant causes major disorders: aged leaves which twist and wither, poor twinning in grains, rotted roots, uneven ripening. By applying potassium sulfate this shortcoming is corrected.In the soil the potassium is highly spread, but only 1-3% of the total potassium in the soil is the one exchangeable of the soil solution. It is expressed as K parts per million.
A soil poorly supplied in potassium has a parts per million count lower than 66. A good soil has between 132 and 200 parts per million, and a very good one has over 200 parts per million.
SULFUR
The sulfur in the plant favors the vegetative growth, the photosynthesis, the frost resistance, the healing of wounds, the germination of seeds. Its lack is manifested by the yellowing of young leaves. Its lack is not detected on chernozem and on soils rich in humus. If potassium sulfate, magnesium sulfate or ammonium sulfate is applied, the problem is solved. The sulfur in the soil is poor if it is below 5 parts per million.
MAGNESIUM
The magnesium is in charge of supplying the nitrogen and phosphorus to the plants’ cells. It is absolutely necessary for the plants. When the first symptoms of deficiency are manifested the soil is fertilized with moderate quantities of magnesium.
CALCIUM
The calcium is present in all the cells, especially in the old ones. It offers elasticity to the cell membrane; it forms the nodules on the roots of leguminous plants. In small quantities it is necessary for the growth of all cells.
Its lack leads to the ceasing of growth and the withering of the growth peaks, while the excess of calcium makes the micro elements inaccessible to plants.
SODIUM
The sodium is not absolutely necessary for plants. Crop plants do not tolerate large quantities of sodium. In the lack of potassium some plans develop a higher need for sodium. Beets, celery, carrot, cabbage, cotton, oats, barley, alfalfa, potato, corn are sensitive to sodium (saline soils).
CHLORINE
The chlorine enhances the succulence of tissues being useful especially for sugar beet and tomatoes and regulates the permeability of cells.
SILICON
In small quantities it is necessary for all plants in order to obtain a normal growth. More silicon is found in cereals and in grass herbs.
ALUMINUM
It has a reduced physiological role and is found in small quantities in plants. It enhances the resistance of plants when associated with boron and molybdenum.
The role of the chemical micro elements
IRON
The iron is a micro element with catalytic and dynamic role. It is present in large quantities in spinach, nettle and tea.
Its lack causes the yellowing and the bleaching of young leaves.
Sprayings of iron sulfate in the form of dilutions are applied on plants.
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