Nitrogen is a plant stimulator, regulator and
a carrier of elements. For plants to benefit from nitrogen, the elements
must first be mineralized. This mineralization is carried out by
microbes that metabolize nitrogen, turning it into nitrite and then to
nitrates. Feeding the soil with organic matter and biological nutrients will stimulate
microbial activity and significantly improve the N.P.K. exchange. During the growing season plants fix carbon dioxide by photosynthesis.
Around 20 to 25 percent of this fixed carbon is returned to the soil
through plant roots.
Agriculture involves not only the physical properties and mineral
structure of the soil, but also the process by which organic matter is
transformed into humus by microbes,
fungi, earthworms etc. Incorporating
crop residue and other organic mater into the soil promotes microbial
growth which in turn promotes humus production and soil fertility.