Fertilizers are substances, mostly mixtures of mineral elements, designed to provide plants with extra nutrients in order to improve their growth and increase the yield and quality of crops. The action to provide fertilizer called fertilization. Fertilizers are part of fertilizer products, with the amendments.
Fertilization takes place in the agriculture and gardening activities.
The fertilizers were used even in ancient times, when we added to the soil, empirically, phosphate bone (or not calcined), nitrogen animal and human, potassium ash.
Role of fertilizer
To carry the process of their vegetative life, plants need water, almost twenty nutrients they can form mineral in the soil, carbon dioxide (CO2) provided by the air, and " solar energy for the synthesis of chlorophyll.
The basic elements, nitrogen (N), potassium (K), phosphorus (P), we are talking about the type of NPK fertilizer if the three are associated together. Otherwise we speak also of N, NP, NK, PK;
Secondary elements, calcium (Ca), sulfur (S), magnesium (Mg),
The trace elements such as iron (Fe), manganese (Mn), molybdenum (Mo), copper (Cu), boron (B), zinc (Zn), chlorine (Cl); sodium (Na), cobalt (Co), vanadium (V) and silicon (Si).
These secondary elements are usually in sufficient quantities in the soil, and they are added only in the event of failure.
Plants need relatively large quantities of material. Nitrogen, phosphorus and potassium are the elements that we must add the most ground, and they form the basis of most fertilizers sold today. Nitrogen is the most important of them, and the most controversial because of the problem of leaching, linked the high water solubility of nitrates. For the Haber-Bosch process one percent of the energy consumed by humans produce ammonia, which provides half of the nitrogen necessary for agriculture.
Calcium Lime is a source of calcium and dolomitic lime supplies of calcium and magnesium. Sulfur is usually present in sufficient quantities in the soil.
Types of fertilizers
The fertilizer can be of three types: organic, mineral and organo-mineral
Organic fertilizers are usually of plant or animal origin. They can also be synthesized (urea for example).
The former are typically industrial wastes such as waste from slaughterhouses (blood dried, roasted Horn, fish waste, sewage sludge water). They are interesting in their use of nitrogen in relatively slow decomposition, and by their actions towards the rapid growth of soil microflora, but do little humus in the soil stable.
The latter may include vegetable waste (greens), composted or not. But it can also be specially cultivated plants as green manure or prepared for this purpose (nettle manure, seaweed). They are also byproducts of livestock, such as manure (composition of most of the manure: plant litter and manure - who are not animal matter but plant more or less digested), manure, manure, etc..
The principle of green manure resumed the ancient practice which consists of burying weeds. It relies on intercropping, which is buried on the spot. When it comes to legumes such as alfalfa or clover, we get more enrichment in soil nitrogen because their root system combines bacteria of the genus Rhizobium able to fix atmospheric nitrogen. To make the technique more effective, we plant seeds advance with the bacterium associated.
The mineral fertilizers are substances of mineral origin, produced by the chemical industry, either by exploiting natural reservoir (phosphate, potash).
The chemical industry operates mainly in the production of nitrogen fertilizers, which passes through the synthesis of ammonia from nitrogen from the air, with a substantial infusion of energy supplied by natural gas (which also provides the 'hydrogen). An ammonia are derived and urea nitrate. She also participates in the manufacture of fertilizer complexes, which are formed by salt resulting from the reaction of a base with an acid. The compound fertilizers can be simple mixtures, sometimes done by the distributors (cooperatives or dealers). We call these mixtures of Bulk Blending.
There are fertilizers simple (only one nutrient) and compound fertilizers (which may contain two or three). The name of mineral fertilizers is normalized, by reference to their three main components: NPK. The fertilizer can be simple nitrogen, phosphate and potash. Fertilizers are noted binary NP or PK or NK, the ternary NPK. These letters are usually followed by numbers representing the respective proportions of the elements. The industrially produced chemical fertilizers contain a guaranteed minimum amount of nutrients, and it is listed on the bag.
For example, the formula 5-10-5 indicates the percentage of nitrogen (N), phosphorus (P) and potassium (K) in the fertilizer, or 5% N, 10% P2O5 and 5% of K2O.
The contribution is expressed as nitrogen, and N is provided either in the form of nitrate NO3, ammonia NH4 or urea. The constraints of the storage form incite nitrate fertilizer distributors to turn to forms ammoniacales urea.
Phosphorus is expressed as P2O5 but provided in the form of calcium phosphate or ammonium.
Potassium is expressed as K2O but provided by chloride, nitrate and potassium sulfate.
Fertilizers organo- minerals resulting mixture of mineral fertilizers and organic fertilizers.
Composition of fertilizer
Some examples of simple fertilizer
Urea (46% nitrogen), ammonium sulfate (SA, 21% nitrogen), ammonitrate (PP, 33.5% nitrogen) and the lime nitrate (CAN / NAC until 'at 27% nitrogen) containing only nitrogen (N);
Single super phosphate (SP, 18% phosphorus) or triple super phosphate (TSP, 46% phosphorus) only contain phosphorus (P2O5)
Potassium chloride (60% potassium) contains only potash (K2O). Sulfate of potash (SOP, 50% K2O) also contains 18% of sulfur.
Other fertilizers, which, in addition to the major nutrients, contain sulfur (S) may include fertilizers simple: sulfate of ammonia or SA, which has 24% of sulfur and the SSP, which has 12%.
Some examples of compound fertilizers
Diammonium phosphate contains both N and P. The formulas used are the 18-46-0 and 20-20-0.
Potassium nitrate contains both N and K.
Application of fertilizer
Typically, fertilizer is incorporated into the soil, but they can also be made by the irrigation water. The latter technique is used for both crops in soil (traditional), as above ground (on a substrate more or less inert, as potting soil, peat, rock wool, vermiculite, etc.). Another technique, hydroponic gardening, helps feed the plants with or without substrate. The roots grow through a nutrient solution fertilizer-more-water flowing from them. The composition and concentration of the nutrient solution must be constantly readjusted.
In some cases, part of the fertilization can be achieved through foliage, spraying. Indeed, the leaves are able to absorb fertilizers, if they are soluble, and if the leaf surface is wet long enough. This absorption, however, remains limited in quantity. Thus, rather trace elements can be made as well, given the small amounts necessary to plants.
On acid soils, we can proceed to liming to raise the pH. This serves to increase the effectiveness of fertilizers by promoting assimilation by plants of nutrients in the soil.
The fertilizer should be used with caution. It is generally suggested
To avoid excesses, because beyond certain thresholds additional material not only have no economic interest, but more likely to be toxic to plants (especially micronutrients), and damage the environment;
To cope with their effects on soil acidity;
To take account of the possible interactions between chemical elements;
To take into account the limitations imposed by other factors of production.
The fertilizer is the amount of fertilizer to provide for a certain area or a certain number of plants. Ideally, the amount should be paid
To be enough to cover the needs of the plant (to ensure efficiency, quality, the rate of growth or beauty desired)
But not exceed (in order to minimize the cost of fertilization, as well as environmental impact. Too high a dose can also damage a culture).
The user will be based fertilizers often on the concept of recommended dose
The recommended dose is the application rate suggested by agricultural research institutes, public or private, some associations or NGOs, or by marketing companies. She will be given in terms of number of bags to be used (with specified proportions NPK contained in a bag), either directly in terms of the quantity of each item to contribute to the hectare, or amount to be contributed by plant or hole planting.
Recommended rates vary according to culture, the variety used, soil type, climate etc.…
What is the easiest way to calculate the amount of nutrients found in a bag of fertilizer?
The easiest way is to divide the numbers printed on the bag of 50 kg / 2 and those marked on the bag of 25 kg per 4. Thus, in a bag of 50 kg whose formula is 15-5-20, we have the following quantities of nutrients:
15 / 2: 7.5 kg N (Nitrogen)
5 / 2: 2.5 kg P2O5 (quantity of phosphate)
20 / 2: 10 kg K2O (quantity of potassium)
A total of 20 kg of element for a bag of 50 kg of fertilizer.
1) The recommendation is: application of 60 kg N per hectare in the form of urea, which contains 45% N. How many bags predict?
46 divided by 2 is equal to 23: the division by 2 corresponds to the weight of the bag: 50 kg. Each bag contains 23 kg of nitrogen.
60 divided by 23 equals 2.6. For example, about two sacks and two thirds of a bag of the product are needed to cover a hectare
2.6 sacks * 50 kg: a total of 130 kg of urea, should be applied per hectare.
2) How much urea used for a range of 500 meters?
If the area of the field is 500 meters required amount of urea is one twentieth of that for one hectare is 6 ½ kg (for a reminder, a hectare is 100 * 100 (10000 meters).
3) If the recommendation is to use a fertilizer 60-30-30, what happens if you use a fertilizer 15-15-15?
If you only use the fertilizer you apply
- Twice as much phosphorus and potassium (economic loss and risk to the environment)
- Is only half of nitrogen needed (hence deficiency)
In this case - Or buy a fertilizer 60-30-30 to fertilize your culture
- Or do only half in the form of fertilizer 15-15-15, and buy another fertilizer containing only nitrogen simple.