About fertilizers

1. Introduction

The most important measure to increase the production potential of the earth is the administration of fertilizers. This consists in the addition of mineral substances, decreased in soil from different causes, and support in this way, the needs of development of plants, leading to increased productivity.
Setting the type of fertilizer most suitable for plants to be grown, while the administration and the optimal amount of fertilizer particularly ensure increased productivity in general, 50%, and even in some cultures by 80%.
Nutritious substances enriching the land and also improving the physical, chemical and biological characteristics of the fertilizers plants provide an environmental and development conditions incomparably better.

To grow and develop normally, plants require carbon, hydrogen and oxygen - which they take in air and water - plus 13 mineral elements essential nutritious substances known or fertilizers, which normally take from the soil. After a long and continuous use of soil, it decrease nutritious substances and requires human intervention supported by the application of specific chemical fertilizers, depending on soil gaps.
Therefore, fertilizers replace nutrients that plants absorb it from soil.
Without the use of fertilizers yields would be substantially reduced.

2. Methods of applying fertilizer

To use the most effective fertilizers, and how the administration of these is of particular importance.
Establishing proper fertilizer management is the factor that determines the effectiveness of it.
In principle, should be pursued as a nutritional substance to be the most active root zone of plants;must consider that the depth of penetration of plant roots, and range up to that spread, differ from one species to another depending on the variety, hybrid, etc.

3.Time management of chemical fertilizers

The period of using fertilizers is different depending on soil and climate conditions, and also the type of plant.
Soil, by its physical, chemical and biological influences to a great extent the management of fertilizers.
During the flush seeds, among the loom roots of the plant, an important fact is that the amount of nutrients should exist in a sufficient quantity.This is the basic criterion in determining the optimal period of managing fertilizers.
Otherwise, the efficiency expected by administration of fertilizers can be much lower.
From this point of view, it is not possible to recommend a standard schedule regarding the administration of fertilizers.
However it is possible to determine some general characteristics regarding the period of NPK fertilizer administration, considering his basic nutritional elements.
The fact that the nitrogen fertilizers are very active in soil and can be easily washed by pluvial waters, by the irrigation or evaporating under gas may rise damages.
To prevent such losses, to maintain soil nutrients when you most need them, sometimes it is not administrated the entire quantity of nitrogen in the sowing or growing of plants, the administration being made in stages, during certain periods of plant growth.
Regarding cereals, among the sowings it is administrated also urea, which has by washing small losses in the soil.
Before the seeds twinning, it will be used the fertilizer based on ammonium nitrate and calcium nitrocalcar (CAN), and if it can not be purchased it is used the urea before the rain.
In regions where the wheat crop is preponderant in dry years should be abandoned in the second administration of nitrogenous fertilizers.
In soils where has been made deep layers, in years with normal rainfall, it is required in sufficient quantities the administration of nitrogenous fertilizers. If at the fruit plantings will be noticed the lack of nitrogen,in the fall and before efflorescence, it will be administrated by spraying the urea in 0,5-1,0% concentration. It can also be administrated nitrous fertilizer in the soil, by spraying the strain around the strain tree, after which it is incorporated in the soil with a rake.
However, in orchards with fruit trees, where it is possible to work the soil between rows of tractors, fertilizers will be administrated during one year in the NS direction between rows, and in the second year in the EV direction between rows. In the vineyard from nitrogenous fertilizers, it will be administrated half nitrocalcar during the February-March work, and half in the form of urea after the first spade.For vegetables fertilizers are given once or twice, taking account of the vegetation. The administration is being made half at 15 days after planting, and the other half after the binding of fruit, the fertilizer being administrated at about 10-15 cm from the plant stem and mixing it with the soil.
After the application period of fertilizers it can be distinguish 3 main methods, namely:
- fertilization before sowing / planting, called the basic fertilization
- fertilization with sowing / plantation
- fertilization during vegetation.
Fertilization before sowing / planting
It combines with the work of the soil, with deep plowing,under the turf,it is incorporating the most part (base) of the fertilizers dose.
A part of fertilizers can be incorporated also with the work before sowing, in this case using slightly soluble fertilizers wich can be used by plants at the begining of growing season.

Fertilization with sowing / plantation
For plants that resemble in rows or in nests, fertilizers are applied with special sower, which leaves on the same row with sowing both seeds and fertilizers at the nest.
Such a fattening provides the nutrition of the plant for a period of 20-30 days from the appearing.

Fertilization during vegetation
It is known as an additional fattening and it's purpose is to fill the needs of the plants in nutrient elements during certain critical periods of their nutrition.

4. The management of fertilizers

Establishing proper the management of fertilizers is the factor that determines the effectiveness of it.
In the administration of fertilizers are used, mainly 5 ways of applying it:
- by spraying
- by incorporation as a string (band)
- vertical and lateral
- by spraying the leaves
- with irrigation water.

Administration by spraying
By this method fertilizers are sprinkled with an aggregate or by hand, scattered before plowing soil or immediately after sowing, or it can also be administrated after the plants have grown a little; then, with the processing of soil, fertilizers are incorporated.
Administration by spraying fertilizer it is being made so:
- At the productive soil - while the plants begin to grow around the roots;
- While fertilizing is given in addition;
- While administrating nitrogen fertilizers soluble in water and when plants are grown between the rows which are not sowing;
- this method leads to saving labor and time.

Administration as a string (tape)
With this method fertilizers are administered before sowing at a depth of 3-5 cm below the seed / plant ready to be replanted or in small digging made at 5-8 cm distance from the plant after which are covered with earth. This method applies to:
- Plants sown in lines or where the distance between the strings is very large
- In soil wich has the fixing capacity high in the period that will be managed phosphatic fertilizers or potassium.
Research conducted both in country and abroad shows that the management of fertilizers by String (band) method is more effective. When the fertilizer is used in soil by this method, poorly developed roots of young plants will use more efficient the fertilizer wich lays next to it, and so the plant will grow faster. On the other hand, the fertilizer nutrients (especially phosphorus), will continue to be useful to the plant much longer.

Managing fertilizer lateral or vertical
For the new plants the fertilizer will be given top or side. This method is used mainly to manage nitrogen fertilizer during early spring.
Vertical (top) administration is made by spraying, and the lateral one is made by administering the fertilizer between rows of the plants.

Administration fertilizer by spraying the leaves
Generally, when it is observed the absence of microelements at the fruit trees and growing plants, the fertilizer dissolved is administered by spraying.
Substances of fertilizer will penetrate through the pleat or leaf cells. The method is applied in regions with a very hot or a very cold climate, NPK type fertilizers will be given very low.
Fertilizers being administered in the form of solution it will be taken care that the leaves of the plants will not be wet. By this method fertilizers can not be administered with substances against pests, with the remark that fertilizers should not be administered with anti-noxius containing calcium and sulphides or only sulphides.
If it is noticed the lack of nitrogen is possible spraying the leaves maximum with urea.

Managing fertilizers with water irrigation
By this method the fertilizer is used mixed with water irrigation. This method is particularly applicable to the crops of sugar beet, lucerne, clover, etc. Attention should be given to the fact that irrigation water should not be too limestone.

5. Factors influencing the economic use of fertilizers

The economic and balanced use of fertilizer is influenced by various factors such as plant, soil and climate.
Plants assimilate from soil nutrients in amounts that vary depending on the periods of development. If, in the same conditions, nutrient requirements vary from plant to plant, assimilating elements of nutritious fertilizers also varies depending on the plant roots.
Therefore, as long as the fertilizer is taken closer to the plant roots, the plants will absorb more substances that are necessary.
Even if there are other factors, the heat and pluvial distribution influence largely the process of assimilation by the plant of nutrients from fertilizer.
Temperature and soil moisture, air temperature and, in particular, pluvial conditions are important factors regarding the efficiency of fertilizers. Knowledge of the physical, chemical and biological characteristics of the soil has an overwhelming importance regarding the economist and balanced use of fertilizers.

6. Conditions for an efficient use of the fertilizer

An efficient and beneficial management of fertilizers is possible by knowing the type and quantity of fertilizer that the plant needs, and also the management of fertilizer in the best period and the most appropriate method.
In other words, to achieve results through management of chemical fertilizers,it is required to be taken account of the following conditions:
- administration of an appropriate fertilizer
- managing the amount of fertilizer that the plant needs
- managing fertilizer at the right time
- the best management of fertilizers in the most appropriate situation, in order to meet these conditions is absolutely necessary to conduct soil analysis.