About Fertilizer
The Elements of Fertilizer
Introduction
Fertilizers are any natural or manufactured material, which contains at least 5% of one or more of the primary nutrients (N, P2O5 or K2O). Industrially manufactured fertilizers are called mineral fertilizers. Mineral fertilizer is a material in which the declared nutrients are in the form of inorganic salts obtained by extraction and/or by physical and/or chemical industrial processes also termed fertilizer. Organic Fertilizer is a fertilizer material of animal or plant origin. It should be noted that sometimes some materials might be applied to soil primarily to improve the physical condition of the soil, in particular to correct soil acidity or alkalinity. Such materials may contain plant nutrient but they are not fertilizers. They are referred to as soil conditioners, amendments or ameliorants. Examples include lime for correcting soil acidity, and gypsum for amending sodic soils.
Fertilizers that contain only one primary nutrient are referred to as straight or simple fertilizers. Examples of some straight fertilizers are urea (46%N), ammonium sulphate or sulphate of ammonia (21%N and 23% S), and calcium ammonium nitrate (27%N).
Others include single superphosphate (16-20% P2O5), triple or treble superphosphate (46% P2O5) and muriate of potash (60% K2O). The terms P2O5 and K2O are conventionally used to express the fertilizer nutrients ‘phosphate’ or ‘phosphorus’ and ‘potash’ or ‘potassium’.
They are the oxides of the elements P and K. They are inter-convertible: P2O5 x 0.43 = P; P x 2.29 = P2O5; K2O x 0.83 = K; K x 1.20 = K2O. Those containing two or three of the primary nutrients are called multi-nutrient fertilizers, sometimes also called binary (two-nutrient) or ternary (three-nutrient) fertilizers. Fertilizersthat contain two or more major nutrients. For example: Diammonium phosphate, which contains 2 nitrogen and P2O5, and NPK formulations which contain all three major nutrients. Most multinutrient fertilizers can be produced by dry bulk blending (physical mixing) of the separate components—such as urea; DAP and MOP are physically mixed to form NPKs or they can be produced by chemical reaction to produce complex compound fertilizers—like reacting ammonia, phosphoric acid, and MOP to produce different grades of NPKs Or by dry or wet granulation of urea, DAP, and MOP to produce NPKs
Excerpt
Fertilizer Us in Nigeria
As in most parts of tropical Africa, the traditional method of maintaining soil fertility and productivity in Nigeria has, hitherto, been the bush-fallow system whereby arable land is allowed to revert to fallow after 3 – 4 years of continuous cultivation. The system evolved out of natural exigencies and the degree of regeneration of soil fertility is generally dependent on the length of the fallow period, which, in turn, is related to the availability of land. In view of growing human population and other socio-economic pressures, attempts were made to shorten the fallow period from about 7 – 10 years to 2 – 3 years by planting leguminous and grass fallows. Although it was clearly demonstrated that soil fertility could be effectively maintained in this way, its acceptance by the peasant farmer was hampered by the tedium of land preparation with native hoes and the economics of the practice;
it was not an easy task convincing a farmer to adopt a system that included unproductive fallows.
The next historical development was to replace the fallow system with the use of manures particularly where there were large numbers of animals. This brought into eminence the agricultural value of Farm Yard Manure (FYM), including poultry dropping, dung and house-hold refuse. By the late 1940s the benefits of FYM had been so established that penning of cattle on the farm and mixed farming were being actively encouraged by the Nigerian Government.
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