Fertilizers

Fertilizers
Fertilizers are a type of chemical product that is used to promote plant growth, the principal nutrients in a fertilizer are: Phosphorus, Nitrogen, and Potassium and some others nutrients are used in smallers amounts. Fertilizers are spread on the surface of the soil, and also sprayeddirect on leaves.
There are two types of fertilizers: Organic and inorganic.

Environmental effects of fertilizer use Water Eutrophication
The nitrogen-rich compounds, which are found in fertilizer run-off is the main cause of a severereduction of oxygen in many parts of the ocean, especially in coastal areas, the consequent lack ofdissolved oxygen is reducing the ability of these areas for sustaining ocean life . Visually, thewater can become cloudy and discolored (green, yellow, brown or red).

high rates of nitrogen fertilization in order to maximize the productivity of crops, combinedwith the high solubility of fertilizers leads to increased surface water runoff and leaching intogroundwater. The use of ammonium nitrate ininorganic fertilizers is particularly detrimental, as plants absorb ammonium ions, preferably on the
nitrate ions, whereas the nitrate ions in excess, are not absorbed dissolve ( by rain or irrigation) for the flow of groundwater.


Benefits of organic fertilizer

Besides increasing the production of fertilizers and plants directly, organic fertilizers can enhance biodiversity (soil life) and long-term productivity of the soil and may prove to be a large deposit of carbon dioxide in excess.

organic nutrients increased the abundance of organisms in the soil by providing organic matter and nutrients in organisms such as mycorrhizal fungi (plants that aids in the absorption of nutrients), and can dramatically reduce the external inputs of pesticides, fertilizers and energy, the cost decrease yield.

Sources
Animal
Animal-sourced Urea , are suitable for application organic agriculture, while pure synthetic forms of urea are not. The common thread that can be seen through these examples is that organic agriculture attempts to define itself through minimal processing, as well as being naturally-occurring or via natural biological processes such as composting.

Plant

Cover crops are also grown to enrich soil as a green manure through nitrogen fixation from the atmosphere.