Hi guys, hoping you are having a good time. It’s January and I know many are digging deeper into their pockets for school money. God forbid school heads who are coming up with exorbitant school fees figures here in Kenya.
That aside, I would like you and me to increase our knowledge reserve of essential plant nutrients with regard to Nitrogen.
The big question is; What is the ultimate source of Nitrogen??
One needs to know that, firstly Atmospheric Nitrogen (N2) forms 78% to 79% of Nitrogen. Nevertheless, acquisition of nitrogen requires the breaking of an exceptionally stable triple covalent bond between the two nitrogen atoms to produce ammonium (NH+4) or nitrate (NO-3) which is taken up by plants.
Secondly, Nitrogen can be tapped by Biological nitrogen fixation by legumes. Examples of these legumes include desmodium, (Sesbania sesban), soybeans. This is made possible because there is a symbiotic relation between legumes and bacteria. Case in point is;
Rhizobium- this is a fast growing acid producing bacteria and the
Bradyrhizobium- this is a slow growing non acid producing bacteria.
They are all found in nodules of certain legumes.The bacteria infect the root hairs,cortical cells then the nodules where nitrogen fixation takes place.
In an agricultural system, this is the principal way of N-fixation.
Thirdly, a Nitrogen source is the industrial manufacture of Nitrogen fertilizers such as ammonium sulphate, ammonium nitrate, calcium ammonium nitrate, urea, and NPK.
A fourth Nitrogen source is organic decomposition; Nitrogen in residues undergoes decomposition to form organic nitrogen through microbial sythesis.
Fifthly, another source of Nitrogen comes through precipitation, industrial gaseous emissions into the atmosphere are dissolved by rainfall and returned to the soil.
Lightning plays an important role here in that it breaks the stable triple bond of Atmospheric nitrogen thus fixing Nitrogen into the soil.