Soil changes are made by adding fertilizer to the soil. There is bulky organic fertilizer, such as cow manure, bat guano, bone meal, and organic compost and green manure crops.
Though many governments and agricultural departments go to great steps to increase the supply of organic fertilizers, such as bulky organic manures and composting materials, there are just not enough of these fertilizers available to meet the existing and future fertilizer needs.
The important types of chemical fertilizers are usually classified according to the three principal elements, namely Nitrogen (N), Phosphorous (P) and Potassium (K), and may, therefore, be included in more than one group. Compared to organic compost, chemical or inorganic fertilizers also have the added advantage of being less bulky. Being less massive makes chemical fertilizer easier to transport, both overland and from the soil into the plants itself, because they get to be available to the plant relatively quickly when incorporated as part of the plant-food constituents.
Organic and Inorganic Chemical Nitrogenous Fertilizer types
This type of fertilizer is divided into different groups according to the manner in which the Nitrogen combines with other elements. These groups are:
- Sodium Nitrates,
- Ammonium Sulphate and ammonium salts,
- Chemical compounds that contain Nitrogen in amide form, and
- Animal and plant by-products.
1. Sodium Nitrates
Sodium Nitrates are also known as Chilean nitrate. The Nitrogen contained in Sodium Nitrate is refined and amounts to 16%. This means that the Nitrogen is instance available to plants and as such is a valuable source of Nitrogen in a type of fertilizer.
2. Ammonium Sulphate
This fertilizer type comes in a white crystalline salt form, containing 20 to 21% ammoniacal nitrogen. It is easy to handle and it stores well under dry conditions. However, during the rainy season, it sometimes forms semi-solids.
3. Ammonium Nitrate
This fertilizer type also comes in white crystalline salts. Ammonium Nitrate salts contain 33 to 35% nitrogen, of which half is nitrate nitrogen and the other half in the ammonium form. As part of the ammonium form, this type of fertilizer cannot be easily available from the soil.
4. Ammonium Sulphate Nitrate
This fertilizer type is available as a mixture of ammonium nitrate and ammonium sulfate and is recognizable as a white crystal or as dirty-white granules. This fertilizer contains 26% nitrogen, 3/4 of it in the ammonia form and the remainder (i.e. 6.5%) as nitrate nitrogen. Ammonium Sulphate Nitrate is non-explosive, readily soluble in water and is very quick-acting.
5. Ammonium Chloride
This fertilizer type comes in a white crystalline compound, which contains a good physical condition and 26% ammonia nitrogen. In general, Ammonium Chloride is similar to ammonium sulfate in action.
This type of fertilizer usually is available to the public in a white, crystalline, organic form. It is a highly concentrated nitrogenous fertilizer and fairly hygroscopic. This also means that this fertilizer can be quite difficult to apply.
7. Organic Nitrogenous Fertilizers
Organic Nitrogenous fertilizer is the type of fertilizer that includes plant and animal by-products. These by-products can be anything from oil cakes to fish manure and even to dried blood. The Nitrogen available in organic nitrogenous fertilizer types first has to be converted before the plants can use it. This conversion occurs through bacterial action and is thus a slow process.
8. Rock Phosphate
As a type of fertilizer, rock phosphate occurs as natural deposits in some countries. This fertilizer type has its advantages and disadvantages. The advantage is that with adequate rainfall this fertilizer results in a long growing period which can enhance crops.
Superphosphate is a fertilizer type that most gardeners are familiar with. As a fertilizer type one can get superphosphate in three different grades, depending on the manufacturing process.
The following is a short description of the different superphosphate fertilizer grades:
- Single superphosphate containing 16 to 20% phosphoric acid;
- Dicalcium phosphate containing 35 to 38% phosphoric acid; and
- Triple superphosphate containing 44 to 49% phosphoric acid.
Basic slag is a by-product of steel mills and is used as a fertilizer to a lesser extent than Superphosphate. Slag is an excellent fertilizer that can be used to amend soils that are acidic because of its alkaline reaction. For slag application to be an effective fertilizer it has to be pulverized first.