MINERAL FERTILIZATION
Mineral fertilization is the main factor in increasing the yield of crops, and maintaining their cultivation at a sufficiently high level. The need for this fertilization results from the insufficient resources of digestible plant nutrients in the soil and their depletion by the cultivated plants. It is therefore essential to rationally feed plants with the most important ingredients, to which it belongs: azote (N), phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca). These ingredients are called macronutrients, because they are taken in significant amounts.
For normal development and yielding, the plant requires 16 ingredients. Three of them, tj.: coal, hydrogen and oxygen., draws from air and water through its roots and shoots. the other ingredients, tj.: azote (N) – papilionaceous plants also from the air, phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe) and micronutrients: mangan (Mn), zinc (Zn), copper (Cu), bor (B), molybdenum (Mo), chlor (Cl), draws from soil or nutrient solution with the help of roots. These ingredients can also be supplied to the plant in a greater or lesser amount by the so-called. foliar fertilization – through the leaves. Therefore, in addition to macronutrients for fertilization, we use the so-called. micronutrients, mentioned above. The plant can use ingredients from the substrate or from fertilizers, if certain conditions are met. Among others, these ingredients must be easily absorbed by the plant, i.e.. easily soluble in water, the roots must be surrounded by an adequate amount of air and water.
SOIL PROPERTIES AND FERTILIZATION
The nutrients that the plant needs are retained by the soil in various ways. Water-soluble potassium compounds, calcium and nitrogen (as long as it is in ammonium form) are caught on the surface, flowing particles or the finest particles of humus. Whereas nitrogen, in the form of nitrate, it is not retained by the soil, therefore, saltpetre is only used then, when the plants have developed their root system sufficiently and can use the fertilizer immediately.
Phosphorus compounds are retained by the soil in this way, that they enter into compounds with calcium in the soil solution, iron and aluminum, forming insoluble compounds – parts. As a result, phosphorus is stored in the soil, but it becomes less available to plants. This process is called phosphorus reverse. This is the main cause of the poor utilization of phosphorus fertilizers by plants. The pH of the soil determines the availability of phosphorus for plants. Sparingly soluble phosphorus compounds are formed on strongly acidic soils. Liming acidic soil, phosphorus bioavailability can be increased. An increase in the amount of caries will have a similar effect, which easily reacts with phosphates, making them easier to digest. In order to increase the absorption of phosphorus, phosphorus fertilizers are produced in the form of granules (mainly superphosphate).
The ability of soil to absorb and retain nutrients depends on the content of floatable particles and humus in it. The value of the soil in this regard can be easily checked, pouring a soil sample into a glass vessel and pouring water over it.
The amount of soil particles in the suspension will indicate its abundance in navigable parts. The dirtier the water is, the more fertile the soil. The above justifies the need to use potassium fertilizers, and even some ammonium nitrogen fertilizers in the fall. However, on sandy soils, smaller doses of fertilizers should be applied once, for this several times a year.
Fine soil particles (ilaste) they also regulate the amount of nutrients in the soil solution, because they absorb their excess, and in the event of a shortage – they return to the solution. As a result, the fine soil particles prevent damage to the roots in the event of an overdose of mineral fertilizers. It is for these reasons that an attempt is made to increase the sorption capacity of the soil by organic fertilization, what the previous chapter deals with.