These organic products transform into organic soil material called humus.
Inorganic nitrogen comes from minerals, and is added to soil from precipitation, or as fertilizers.
Adding N to the soil is done to help living plants grow and remain healthy. However, plants cannot use organic forms of nitrogen so certain microbes living in the soil come to the rescue and convert organic forms of N into inorganic forms that plants can then use. There are different forms of inorganic nitrogen that are available to plants. Luckily there are other kinds of microbes that live in the soil, and close to Earth's surface, that can convert Nitrogen gas into inorganic forms of N that plants can then use. Organic and inorganic nitrogen present in the soil are carried along with the eroded soil particles.