Tuesday, March 24, 2015

Nitrogen Cycle - Importance of Nitrogen ( N )

Source: http://www.physicalgeography.net

Next to water, Nitrogen is one of the important nutrients for Plant Growth and exists in different forms.  Nitrogen is a component of chlorophyll and therefore essential for photosynthesis.  It is the basic element of plants and animal proteins, including the genetic material DNA & RNA and is important in plant growths.

Plants use Nitrogen by absorbing either nitrate or ammonium ions through roots. Nitrogen is readily transported from older tissues to younger tissues and therefore a nitrogen deficient plant will show yellowing in the old leaves.

Nitrogen makes 78% of atmosphere and not readily available for plants but is directly used in nitrogen fixation. Nitrogen may exist in several different chemical forms such as air, water or land.  Soil nitrogen exists in three forms: Organic nitrogen compounds, ammonium ions and nitrate ions.


Nitrogen assimilation into amino acids is the building block for protein in the plant.  In plants nitrogen content varies from 1 – 6 %

Nitrogen is a very dynamic element available in various forms and also undergoes many transformations in and out of the soil.  The sum of these transformations is known as Nitrogen Cycle.

Nitrogen cycle helps us to understand the relationship between many forms of nitrogen and also the ways in which nitrogen may lost from the soil.


Fertilizers with high proportion of Nitrogen are derived from ammonium sources such as Urea, Ammonium sulphate and phosphate. Fertilizer composition can change the pH of the soil.

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