Fertilizer Application:
Definitions:
Soil fertility:
It is physicals condition of the soil which enables the soil to provide nutrients in adequate quantities for balanced plant growth when the growth factors such as light, humidity, temperature and other physicals characteristics are favorable to plant growth.
Fertilizer: it is any natural or artificial substance added to the soil in order to provide one or more nutrients.
Fertilization Efficiency:
It is the rate of increase of production as a result of addition of one unit of fertilizer.

Fertilizer acidity and alkalinity:
The acidic effect of fertilizers comes from the bacterial activity which transfers the Ammonium Nitrogen into Nitrate NO3 through Nitrification

 The Ammonium Nitrogen and the sulpher oxide The acidic effect. The concentration and hydrogen ions in the soil is called the active acidity. The degree of acidity and alkalinity is measure by the PH which ranges between 1-14.
The potassium is added through:
Moist degradation (rainfall).
Dry degradation (dust).
Application of organic and green fertilizers.
Precipitation.
The potassium losses through:
Removal of crops.
Leaching.
Potassium fixation.
Mineralization of organic matters from plant and animal residuals.
Example of potassium fertilizers:
Commercial potassium chloride: It contains 20-30% of soluble K2O.
Potassium phosphate: used as liquid and solid and contains K2O2P2O5.
Secondary nutrients: it include Maganesium,Calcium, Sulphur and they are important for plant nutrition :
Magnesium:
Available in the soil and absorbed in form of Mg + and important in chlorophyll construction and seed formation. The deficiency symptoms are oblivious in the large leaves without affecting the veins .changing the leaves color to reddish purple.
Calcium:
Absorbed in form of iron and it affects the roots and leaves growth and cell walls. The deficiency symptoms is transformation of the leaves in to cup form and curling of the upper buds and cracking and fruits like: Tomatoes and water melon.
Sulphur :
Absorbed in form of sulfur oxides and it affects the formation of amino acid and bacterial needs in pluses. The symptoms are pale greenish of the leaves .Sulphur deficiency is common in sandy poor soils.